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2as Jornadas de Electroquímica e Inovação (2011)

www.e-inov.org

Sensores e Técnicas de Especiação

Universidade do Algarve

Faro

11 – 02- 2011

PROGRAM SCHEDULE 03

ABSTRACT INDEX 04

ABSTRACTS 07

LIST OF AUTHORS 45

LIST OF PARTICIPANTS 47

SPONSORS 49

2ª Jornadas de Electroquímica e Inovação 2011 www.e-inov.org

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3

PROGRAM

08:45-09:00 Registration (Átrium)

09:00-09:15 Opening Ceremony (Anfiteatro Verde)

Theme A: "Electrochemical Sensors"

09:15-10:15 Plenary Lesson: HUBERT GIRAULT "Electrochemical Immunoassay Microchips"

PL1

10:15-11:00 Coffee-Break and Poster Session

11:00-11:30 Keynote Lecture: MARIA GABRIELA ALMEIDA "The pros and cons of nitrite biosensing through redox enzymes"

KN1

11:30-12:00 Keynote Lecture: HENRIQUE LEONEL GOMES "Design of impedance-based sensors using coplanar microelectrode arrays"

KN2

12:00-12:30 Keynote Lecture: EMILIA GHICA

"Redox polymer modified electrodes: from synthesis to applications in sensors and biosensors"

KN3

12:30-13:30 Lunch (Atrium)

13:30-14:15 Poster Session (Atrium)

Theme B: "Speciation Techniques"

14:15-15:15 Plenary Lesson: HERMAN VAN LEEUWEN "Fundamentals of trace metal dynamic speciation"

PL2

15:15-16:15 Plenary Lesson: JOSEP GALCERAN "A review of the concepts, new developments and applications of AGNES"

PL3

16:15-17:00 Coffee-Break and Poster Session

17:00-17:30 Keynote Lecture: LUCIANA ROCHA "Performance of the ex-situ TMFE in speciation studies of trace metals by dynamic electrochemical stripping techniques: SSCP and AGNES"

KN4

17:30-18:00 Keynote Lecture: CORINNE PARAT "Implementation of SSCP and AGNES-SCP with Screen Printed Electrodes"

KN5

18:00-18:30 Keynote Lecture: RUTE DOMINGOS

"Metallic nanoparticles in the environment: tools for evaluating speciation"

KN6

18:30-18:45 Award Presentation and Closing Session


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ABSTRACT INDEX

Ref. Title / Presenting Author Page

PL1 Electrochemical immunossay microchips

H. Girault 7

PL2 Dynamic metal speciation analysis: on ligands and labilities

H.P. van Leeuwen 8

PL3 A review of the concepts, new developments and applications of AGNES

J. Galceran, E. Companys, J. Puy 9

KN1 The Pros and Cons of Nitrite Biosensing through Redox Enzymes

M. G. Almeida 10

KN2 Design of impedance based sensors using coplanar microelectrode arrays

H. L. Gomes 11

KN3 Redox polymer modified electrodes: from synthesis to application in sensors and biosensors

M. E. Ghica, M. M. Barsan, R. Pauliukaite, C.M.A. Brett 12

KN4 Performance of the ex-situ TMFE in speciation studies of trace metals by dynamic electrochemical stripping techniques: SSCP and AGNES

L. Rocha, J. Galceran, J.P. Pinheiro 13

KN5

Implementation of SSCP and AGNES-SCP with screen-printed electrodes for trace metal speciation analysis

C. Parat, A. Schneider, L. Authier, D. Aguilar, E. Companys, J. Galceran, M. Potin-Gautier

14

KN6 Metallic Nanoparticles in the Environment: Tools for Evaluating Speciation

R.F. Domingos, J.P. Pinheiro 15

P1

Repartition of potential, Zn2+ and pH in the Vicinity of Zinc Corroding in Chloride Media

O.V. Karavai, A.C. Bastos, A.A. Ferreira, M.L. Zheludkevich, M.G.S. Ferreira

16

P2 Bio-functionalisation of nanostructured gold surfaces by in-situ dithiocarbamate formation

I. Almeida, A.S. Viana 17

P3 Electrochemical Double Layer at the Hg/Choline Chloride Based Ionic Liquids Interfaces

R. Costa, C.M. Pereira, F. Silva 18

P4 Corrosion and tribocorrosion behaviour of age-hardened Al-SiCp composites with a functional gradient of particles

A.C. Vieira, S. Mischler, A.M. Pinto, L.A. Rocha 19


5

P5

Corrosion rate monitoring of steel in reinforced concrete structures:

comparison between external and embedded sensors

E. V. Pereira, M. M. Salta, I. T. E. Fonseca

20

P6

Electrochemical study of (η6-cymene)ruthenium(II) complexes bearing bis-, tris- and tetrakis(pyrazol-1-yl)borate ligands

L.M.D.R.S. Martins, C. Pettinari, F. Marchetti, A. Cerquetella, R. Pettinari, M. Monari, T.C.O. Mac Leod, A.J.L. Pombeiro

21

P7 Voltammetric Quantification of Catecholamines

I. M. Miranda, M. Araújo, F. Silva, C. M. Pereira 22

P8 Electrochemical Study Of Ammonium Ion Transfer At An Interface Between Two Immiscible Electrolyte Solutions

J.A. Ribeiro, C.M. Pereira, F. Silva 23

P9 Influence of the Substrate on the Self-assembly of Phosphonic Acids Monolayers

J. Cabrita, F.-P. Montforts, L.M. Abrantes, A.S. Viana 24

P10 Formation of ternary lipid bilayers with phase separation on gold

J.T. Marquês, R.F.M. de Almeida A.S. Viana, 25

P11 Modified titanate nanotubular structures for electrochemical applications

O. C. Monteiro, N. Ito 26

P12 Voltammetric Study of Copper Species Immobilized on Multi-Walled Carbon Nanotubes Film-Coated Electrode

J.G. Teixeira, A. Veiga, J. Mirão, A. Candeias, D. M. Teixeira 27

P13

Mediated catalytic electrochemistry of Pseudomonas stutzeri cytochrome c peroxidase: insights into the activation mechanism

P. M. Paes de Sousa, D. Rodrigues, C. G. Timóteo, M. L. Simões Gonçalves, G. W. Pettigrew, I. Moura, J. J. G. Moura, M. M. Correia dos Santos.

28

P14 Distribution of chemical species in aqueous solution near coupled iron and zinc electrodes

A.C. Bastos, O.V.Karavai, M.L. Zheludkevich, M.G.S. Ferreira 29

P15 Modeling corrosion behavior of conductive coatings based on EIS, SVET and LEIS experiments

A. Marques, J.-B. Jorcin , A. Simões* 30

P16 Electrochemical Characterization Of Anodic Treated Titanium Surfaces For Biomedical Applications

A.C.Alves, J.C.S.Fernandes, L.A.Rocha 31

P17 Exploring the behavior of nanostructured Ag catalyst on ethanol electrooxidation

M. C. Oliveira 32


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P18

Biohybrids doped with potassium triflate with potential application in electrochromic devices

M. Fernandes, R. Rego, M. C. Oliveira, R. A. Sá Ferreira, L. D. Carlos, A. Gonçalves, E. Fortunato, V. de Zea Bermudez

33

P19 Zn, Sn and Zn-Sn electrodeposition from Deep Eutectic Solvents

N. Pereira, S. Salomé, P.M. V. Fernandes, C.M. Pereira, F. Silva 34

P20 Corrosion evaluation of WE 54 and AZ 31 magnesium alloys in physiological media

A. Fernandes, M.F. Montemor, J.C.S. Fernandes 35

P21 The Effect of Deformation on the Corrosion Resistance of NiTi

J.C.S. Fernandes, T.M. Silva, M.J. Carmezim 36

P22 Electrochemical study of NiII, ZnII and CuII complexes bearing a sterically hindered scorpionate ligand (TpmsPh)-

L.M.D.R.S. Martins, B.G.M. Rocha, A.J.L. Pombeiro 37

P23 Conducting polymers prepared from Deep Eutectic Solvents

P.M. V. Fernandes, C.M. Pereira, F. Silva 38

P24

The usage of spent zeolite catalysts impregnated by monoethanolamine as corrosion protective additive to reinforced cement: catalyst modification and EIS analysis of mild steel in aqueous media

Y. Morozov, A.S. Castela, A.P. Soares, M.F. Montemor

39

P25 Metal interaction with light expanded clay aggregates (LECA): real pH conditions and its effect on the adsorption of lead, zinc and copper

S. Capelo, M. Caiano, J.P. Pinheiro 40

P26 Voltammetric detection of Domoic Acid at a multiwalled carbon-nanotube electrode

F. Bento, D. Geraldo, R. Oliveira, C. Teixeira, E. González-Romero 41

P27 Metal speciation in seawater: links to bioaccumulation in fish tissues

M. Díaz-de Alba, M. D. Galindo-Riaño, M. García-Vargas 42

P28 Lead speciation in seawater by AGNES and SSCP

M. Díaz-de Alba; M. D. Galindo-Riaño; M. García-Vargas, J. P. Pinheiro 43


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PL1

Electrochemical immunossay microchips

Hubert H. Girault

Laboratoire d’Electrochimie Physique et Analytique, Ecole Polytechnique Fédérale de Lausanne, Station 6, CH-1015 Lausanne, Switzerland

Different strategies for performing amperometric immunoassays in a microchannel will be presented. The first strategy consists in using the wall of the microchannel to carry out the affinity capture between immobilised antibodies and antigens, whilst performing the amperometric detection on an embedded microelectrode array. Here, we shall discuss the different methods to fill the channel either continuously by pumping or repetitively by iterative fillings. The second strategy consists in using magnetic beads to carry out the affinity reaction outside the channel, and to trap these beads within the microchannel to carry out the amperometric detection. In both cases, the kinetic aspects will be discussed in relation to the detection limit, in particular the advantages of performing enzyme amplification in a confined environment. We shall also discuss the physical aspects of magnetic bead trapping in a microchannel. Finally, different systems will be presented ranging from a 8-channel manual system to a fully robotised instrument.


8

PL2

Dynamic metal speciation analysis: on ligands and labilities

Herman P. van Leeuwen

Laboratory of Physical Chemistry and Colloid Science Wageningen University

Dreijenplein 6, 6703 HB Wageningen, The Netherlands [email protected]

For fairly simple metal complex species, the impact of chemodynamic features on the dynamic response in speciation analysis is well understood1. The crucial quantity is the lability parameter LLLL which compares the kinetic flux properties of the complex species ML to its diffusive flux. In its most simple form, LLLL is usually expressed as LLLL = kd DM

1/2 δ / ka1/2 DML cL

1/2 (1) where kd and ka are the rate constants for dissociation and association respectively, DM and DML are the diffusion coefficients of M and ML and δ is the diffusion layer thickness. For a true solution of ligands, cL simply is the free ligand concentration. However, for a dispersion of colloidal or nanoparticulate multisite ligands, the situation is more involved. The metal binding sites are spatially confined to the particulate surface (hard particles) or volume (soft particles), and generally find themselves at an electric potential different from that in the bulk dispersion. The inherent modifications in mass transport2,3 and electrostatic conditions4,5 give rise to major changes in the chemodynamics6 of the complex species. The basic features of these changes will be discussed. Keywords: chemodynamics, lability, multisite, nanoparticulate ligand, colloidal ligand 1. H.P. van Leeuwen, R.M. Town, J. Buffle, R.F.M.J. Cleven, W. Davison, J. Puy, W.H. van Riemsdijk and L. Sigg, Environ. Sci. Technol. 39(2005), 8545. 2. J.P. Pinheiro, M. Minor and H.P. van Leeuwen, Langmuir 21(2005), 8635. 3. J. Buffle, Z. Zhang and K. Startchev, Environ. Sci. Technol. 41(2007), 7609. 4. P. Debye, Trans. Electrochem. Soc. 82(1942), 265. 5. J.F.L. Duval, J. Phys. Chem. A 113(2009), 2275. 6. H.P. van Leeuwen and J. Buffle, Environ. Sci. Technol. 43(2009), 7175.


9

PL3

A review of the concepts, new developments and applications of AGNES

Josep Galceran, Encarnació Companys, Jaume Puy

Departament de Química,Universitat de Lleida, Rovira Roure 191, 25198, Lleida, Spain. tel 00 34 973 70 28 26 fax 00 34 973 23 82 64 e-mail [email protected]

AGNES (Absence of Gradients and Nernstian Equilibrium Stripping) is a technique specifically designed for the determination of free metal ion concentrations [1]. The presentation revise its principles, implementation, validation and applications. In the implementation section we will present: different working electrodes (HMDE, Ir-Hg microelectrode [2], thin film on a RDE [3] and SPE [4]); the various possibilities of blanks (synthetic, shifted and EDTA), the variants of the first stage (one pulse and two pulses [5]) and the variants for the second stage (diffusion limited current and charge from a pulse or LSV or SCP). In the validation we will see agreement with theoretical codes, ISE, SSCP [6] and Resin Titration techniques [7]. As applications we will mention: humic acids studies [8,9]; determination of free Zn in sea water [10]; speciation in river water [11](dealing with anomalous effects arising from low ionic strength [12]); Cu interference on Zn due to intermetallic compounds [13]; the impact of lability on the deposition time requirements [14]; the study of the solubilization of ZnO nanoparticles (thermodynamics and kinetics) and the analysis of Zn in wines [15]. Perspectives will consider new electrodes, other elements and future systems amongst other issues.

Keywords: Electroanalysis, Heavy Metals, AGNES

1. J.Galceran, E.Companys, J.Puy, J.Cecília, J.L.Garcés, J. Electroanal. Chem. 566 (2004) 95. 2. C.Huidobro, E.Companys, J.Puy, J.Galceran, J.P.Pinheiro, J. Electroanal. Chem. 606 (2007) 134. 3. L.S.Rocha, E.Companys, J.Galceran, H.M.Carapuca, J.P.Pinheiro, Talanta 80 (2010) 1881. 4. C.Parat, D.Aguilar, L.Authier, M.Potin-Gautier, E.Companys, J.Puy, J.Galceran. [In Press]

Electroanal., 2011; 5. E.Companys, J.Cecília, G.Codina, J.Puy, J.Galceran, J. Electroanal. Chem. 576 (2005) 21. 6. Domingos R.F., C.Huidobro, E.Companys, J.Galceran, J.Puy, J.P.Pinheiro, J. Electroanal. Chem.

617 (2008) 141. 7. G.Alberti, R.Biesuz, C.Huidobro, E.Companys, J.Puy, J.Galceran, Anal. Chim. Acta 599 (2007) 41. 8. E.Companys, J.Puy, J.Galceran, Environ. Chem. 4 (2007) 347. 9. J.Puy, J.Galceran, C.Huidobro, E.Companys, N.Samper, J.L.Garcés, F.Mas, Environ. Sci. Technol.

42 (2008) 9289. 10. J.Galceran, C.Huidobro, E.Companys, G.Alberti, Talanta 71 (2007) 1795. 11. F.Zavarise, E.Companys, J.Galceran, G.Alberti, A.Profumo, Anal. Bioanal. Chem. 397 (2010)389. 12. J.Galceran, D.Chito, N.Martinez-Micaelo, E.Companys, C.David, J.Puy, J. Electroanal. Chem.

638 (2010) 131. 13. D.Chito, J.Galceran, E.Companys, Electroanal. 22 (2010) 2024. 14. J.P.Pinheiro, J.Salvador, E.Companys, J.Galceran, J.Puy, PhysChem. ChemPhys. 12 (2010) 1131. 15. E.Companys, M.Naval-Sanchez, N.Martinez-Micaelo, J.Puy, J.Galceran, J. Agric. Food Chem. 56

(2008) 8296.


10

KN1

The Pros and Cons of Nitrite Biosensing through Redox Enzymes

Maria Gabriela Almeidaa,b

aREQUIMTE—Departmento de Química, Faculdade de Ciencias e Tecnologia (UNL), 2829-

516 Monte Caparica, Portugal b Escola Superior de Saude Egas Moniz, Campus Universitario, Quinta da Granja, 2829-511

Monte Caparica, Portugal ([email protected])

Nitrite biosensors represent an important R&D field, targeting key applications in the industrial, environmental and biomedical markets. In fact, the ability to discriminate the analyte against interfering species through the integration of highly selective oxidoreductases, is an added value for nitrite screening in food, waters and physiological samples. The redox nature of the catalytic reaction makes electrochemical platforms the natural choice for signal transducers. However, protein immobilization and its electronic communication with the electrode surface are typical obstacles in the fabrication of biosensing devices [1]. In this context, our group has proposed a number of different strategies for the construction of a nitrite biosensor using the fast and robust cytochrome c nitrite reductase from Desulfovibrio desulfuricans, which catalyzes the six-electron reduction of NO2

- to NH4+. Fully integrated

bioelectrodes including synthetic redox mediators combined with a variety of immobilization materials (methyl viologen/Nafion [2], poly(pyrrole-viologen) [3] and anthraquinone-2-sulfonate/layered double hydroxides [4]) were initially proposed. More advanced strategies operating through direct electron transfer [5] and exploiting nanostructured materials [6,7] were lately reported. Nevertheless, despite the value of these works, a number of setbacks need to be overcome in order to reach the commercialization stage. For example, the very negative reduction potentials required to activate nitrite reductases imposes oxygen removal from solutions and diminishes the selectivity of analysis due to unspecific electrode reactions. Very recently, we have also reported a novel biosensor based on cytochrome cd1 nitrite reductase from Marinobacter hydrocarbonoclausticus (converts NO2

- into NO), which was successfully co-entrapped with its physiological redox partner, the electroactive cytochrome c552 [8]. The employment of this electron transfer protein to monitor the enzyme activity proved to be an excellent option since it increases significantly the operating potential (ca. 250 mV vs NHE), therefore solving the above mentioned issues, and eliminates interfering reactions due to non-enzymatic catalysis. For these reasons, the cooperative use of enzymes and their physiological redox partners could become a new trend in the design of electrochemical biosensors. In this communication, the advantages and disadvantages of each approach will be discussed. Keywords: biosensors, nitrites, nitrite reductases, electron transfer. [1] M.G. Almeida et al., Sensors 2010, 10(12) 11530; [2] M.G. Almeida et al. Biosens. Bioelectron. 2007, 22, 2485; [3] S. Silva et al. Electrochem. Commun. 2004, 6, 404; [4] H. Chen et al., Electrochem. Commun. 2007, 9, 2241; [5] Silveira et al. Biosens. Bioelectron. 2010, 25, 2026; [6] C. Silveira et al. Electroanalysis 2010, 22, 2973; [7] C. Silveira et al., in preparation; [8] A.S. Serra et al. submitted.


11

KN2

Design of impedance based sensors using coplanar microelectrode arrays

Henrique Leonel Gomes

Center of Electronics Optoelectronics and Telecommunications (CEOT) Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.

([email protected])

Small signal impedance techniques are often used to address a variety of sensors, such as electronic noses, tongues, electrochemical sensors and cell-based biosensors. The design of the microelectrode array system determines the sensor performance and often it as important as the active material used as sensing layer. By using equivalent circuits which describe the small-signal response of the microelectrodes within the measuring system is possible to perceive how each parameter such as electrode spacing, area, ionic concentration, etc, will affect the ability of the sensor to perform reliable measurements. In this contribution we suggest the guidelines of dominant components for sensing as design parameters.


12

KN3

Redox polymer modified electrodes: from synthesis to

application in sensors and biosensors

Mariana Emilia Ghica, Madalina M. Barsan, Rasa Pauliukaite, Christopher M.A. Brett

Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, PT-3004-535 Coimbra, Portugal

[email protected] The remarkable properties of conducting polymers are inspiring scientists from all fields to create electrochromic devices, capacitors, anti-static coatings, catalysts, electromagnetic shielding devices, as well as electrochemical sensors and biosensors. For sensor construction, various polymers have been investigated; among them redox polymers prepared from the family of azine dyes constitute very promising materials [1]. The monomer dyes have proved to be good electronic mediators that can undergo fast redox reactions with different compounds, whereas the corresponding polymer modified electrodes possess better long-term stability and retain the electrochemical properties of the monomer. For this reason, there has been increased interest in developing new sensors and biosensors based on polyazines [2,3]. The aim of miniaturisation for application in complex matrices is promising; hence more complex electrode assemblies have been investigated as well as new electrode materials. Electrochemical sensors and enzyme biosensors developed on pyrolytically deposited carbon film electrode substrates modified with different polyazines will be described. Nanostructured modified electrodes have been recently prepared including polyazine redox mediator films together with carbon nanotubes immobilised in chitosan matrices [4,5]. Voltammetric electrochemical methods have been advantageously applied to study the synthesis and characterisation of redox polymers, as well as electrochemical impedance spectroscopy and microscopic techniques. Application of the sensors and biosensors in food analysis as well as in enzyme inhibition for biotoxic trace metal determination in the environment will be described [6]. Keywords: redox polymers, polyazines, carbon film, carbon nanotubes, chitosan References: [1] A.A. Karyakin, E.E. Karyakina, H.-L. Schmidt, Electroanalysis 11 (1999) 149. [2] R. Pauliukaite, M.E. Ghica, M. Barsan, C.M.A. Brett, J. Solid State Electrochem., 11 (2007) 899. [3] M.E. Ghica, C.M.A. Brett, Anal. Lett. 39 (2006) 1527. [4] R. Pauliukaite, M.E. Ghica, M.M. Barsan, C.M.A. Brett, Anal. Lett.,

43 (2010) 1588. [5] M.E. Ghica, C.M.A. Brett, Microchim. Acta, 170 (2010) 257. [6] M.E. Ghica, C.M:A. Brett, Microchim. Acta, 163 (2008) 185.


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KN4

Performance of the ex-situ TMFE in speciation studies of trace metals by dynamic electrochemical stripping techniques:

SSCP and AGNES

Luciana Rocha a, Josep Galceran b, José Paulo Pinheiro c

a Department of Chemistry/CICECO, University of Aveiro, 3810-193 Aveiro, Portugal

b Department of Chemistry, University of Lleida, Rovira Roure 191, 25198 Lleida, Spain

This work is dedicated to the memory of Professor Helena Maria Carapuça, by the inspiration, the limitless support and especially by the always demonstrated friendship.

Dynamic metal speciation analysis remains a challenging task, since very few techniques combine the potential to perform dynamic speciation and high sensitivity. Among those are the newly developed electrochemical stripping techniques:

i) SSCP – stripping chronopotentiometry at scanned deposition potential – that is particularly suited for trace metal complexation studies due to its sensitivity and to its capacity to provide information about the dynamic nature of the complexes [1][2];

ii) AGNES – absence of gradients and Nernstian equilibrium stripping – the one allowing the determination of the free metal ion concentration of amalgamating elements [3].

Mercury electrodes play a central role in the success of stripping analysis, due to its highly reproducible, smooth and readily renewable surface. The greatest drawback of these working electrodes, are the extreme toxicity of mercury and the mercury salts employed in its preparation. Alternative electrode materials, which exhibit an analogous electrochemical behaviour but lower toxicity than mercury, have been developed. Still, the mercury electrodes represent the best option in the field of trace metal speciation in natural systems. Over the last decades, the mercury film electrode, prepared by coating a suitable substrate with a thin ‘‘film’’ of metallic mercury, has proved to be a valuable tool in the stripping analysis of trace metals, due to its sensitivity. The present work highlights the potentialities of thin mercury film electrodes (TMFE), preplated onto glassy carbon, in the dynamic speciation studies of lead by SSCP [4] and AGNES [5]. Keywords: thin mercury film electrode (TMFE), scanning stripping chronopotentiometry (SSCP), absence of gradients and Nernstian equilibrium stripping (AGNES), trace metals. [1] H.P. van Leeuwen, R.M. Town, Environ. Sci. Technol. 37 (2003) 3945. [2] J.P. Pinheiro, H.P. van Leeuwen, J. Electroanal. Chem. 570 (2004) 69. [3] J. Galceran, E. Companys, J. Puy, J. Cecı´lia, J.L. Garce´s, J. Electroanal. Chem. 566 (2004) 95. [4] L. S. Rocha, H. M. Carapuça, J. P. Pinheiro, J. Electroanal. Chem. 610 (2007) 37. [5] L. S. Rocha, E. Companys, J. Galceran, H. M. Carapuça¸ J. P. Pinheiro, Talanta 80 (2010) 1881.

c IBB/CBME, Department of Chemistry, Biochemistry and Pharmacy, Faculty of Sciences and Technology, University of Algarve, 8005-139 Faro, Portugal


14

KN5

Implementation of SSCP and AGNES-SCP with screen-printed electrodes for trace metal speciation analysis

Corinne Parata, André Schneiderb, Laurent Authiera, David Aguilarc, Encarna Companysc,

Josep Galceranc, Martine Potin-Gautiera

aUniversité de Pau, LCABIE, UMR 5254 IPREM, Av. P. Angot, 64000 Pau France bINRA, UMR 1220 T.C.E.M., BP 81, 33883 Villenave d’Ornon, France

cDep. Química. Universitat de Lleida, Rovira Roure 191, 25198 Lleida, Spain Corresponding author: [email protected]

Predicting trace metal bioavailability necessitates methods able to quantify the free ion concentration but also to provide some speciation information on both the thermodynamic stability and kinetic lability of metal complex species. Electrochemical techniques, especially stripping methods which use a preconcentration step, provide adequate sensitivity and are, therefore, of particular relevance for trace metal speciation studies. Thus, van Leeuwen et al. have demonstrated that stripping chronopotentiometry at scanned deposition potential (SSCP) allows a straightforward description of the lability [1]. In the same way, Galceran et al. have proposed a technique called Absence of Gradient and Nernstian Equilibrium Stripping method (AGNES), which allows to measure the free metal ion concentration [2]. Both methods are typically implemented with the hanging mercury drop electrode and thus are poorly adapted for on site analyses. The analytical challenge of this study is to develop a thin mercury film screen-printed electrode (SPE) as an alternative device which can be easily deployed on site. First, the SCP parameters have been optimised for SPE in order to reach the complete depletion regime, before constructing SSCP curves [3]. At the same time, the required experimental conditions of AGNES implemented with SPE have been determined [4]. Then the implementation of SCP for the stripping stage (AGNES-SCP) has been considered in order to better deal with possible interferences. Finally, both methods were applied to a synthetic solution containing a complexing ligand and compared with Visual MINTEQ results. SSCP and AGNES-SCP have been successfully implemented with a SPE in synthetic solutions and appear as highly complementary. Thus, SSCP allowed determining the conditional stability constant of the CdNTA and CdPDCA complexes and, in some cases, their association rate constant. In addition, AGNES-SCP allowed to determine the free metal concentration in samples containing different ligands and showing different types of interferences. 1. H. P. van Leeuwen, R. M. Town Journal of Electroanalytical Chemistry 2002, 536, 129. 2. J. Galceran, E. Companys, J. Puy, J. Cecilia, J. L. Garces Journal of Electroanalytical Chemistry 2004, 566, 95. 3. C. Parat, A. Schneider, A. Castetbon, M. Potin-Gautier Analytica Chimica Acta 2011, in press. 4. C. Parat, D. Aguilar, L. Authier, M. Potin-Gautier, E. Companys, J. Puy, J. Galceran Electroanalysis 2011, in press. Keywords: Screen-Printed Electrodes, AGNES, SSCP, trace metals.


15

KN6

Metallic Nanoparticles in the Environment: Tools for Evaluating Speciation

Rute F. Domingosa,*, J.P. Pinheirob

a Centro de Química Estrutural, Instituto Superior Técnico, Av. Rovisco Pais #1, 1049-001 Lisboa, [email protected]

bCentro de Biomedicina Molecular e Estrutural, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, [email protected]

The increasing use of nanomaterials in consumer products has led to increased concerns about their potential environmental and health impacts. It is now understood that these impacts should be ascribed not only to the nanoparticles (NPs) per se but also to their dissolution products. Most of the recent published works examine NP toxicity without characterizing their fundamental properties in well defined medium that are often environmentally relevant. To better understand the transport, fate, and bioavailability of NPs in aquatic systems, it is essential to quantify not only their aggregation but also their dissolution and speciation in presence of different components of natural waters, over a broad range of physicochemical conditions. NPs based on CdS, CdSe and CdTe are interesting for their promising applications in molecular biology, medicine and information technology. Moreover, given their composition, they are likely to be inherently highly toxic. A carboxylate terminated CdTe/CdS quantum dot (QD) from ViveNano Inc. and with a nominal size between 4 and 10 nm was used. Transmission electron microscopy and atomic force microscopy were used to determine the aggregation of the QD. Dissolution and dynamic aspects of metal ion speciation of the QD dispersions were quantified by the new electroanalytical techniques, absence of gradients and nernstian equilibrium stripping (AGNES) and stripping chronopotentiometry at scanned deposition potential (SSCP), respectively. The effects of a various concentrations of homogeneous ligands such as citric acid, nitrilotriacetic acid (NTA), glycine, and histidine at pH 4.5 and 8.5 were evaluated. Dissolution of the bare QD increased for more acidic pH values. In presence of the citric acid and for conditions which favored the dissolution of the QD the dissolved Cd is complexed only by the citric acid; no effect of the carboxylate terminated polymer used by the company to stabilize the QD is observed. The QD dissolution was not affected by the presence of NTA, glycine or histidine at the lowest pH value. At the highest pH value, were a larger stabilization of the QD is expected, and at the two lowest concentrations of citric acid a complexation of the dissolved Cd is observed. Furthermore, the presence of this homogenous ligand seems not to have a large effect in the dissolution of the QD. However, at the highest citric acid concentration a clear impact on the QD dissolution is observed. Also, in presence of glycine and histidine an increased dissolution of the QD was induced. Keywords: Nanoparticles, speciation, AGNES, SSCP


16

P1

Repartition of potential, Zn2+ and pH in the Vicinity of Zinc Corroding in Chloride Media

O.V. Karavaia, A.C. Bastosa, A.A. Ferreiraa, M.L. Zheludkevicha, M.G.S. Ferreiraa,b

aDECV/CICECO, Universidade de Aveiro, Campus Universitário de Santiago,3810-193

Aveiro, Portugal. Tel/fax: (+351) 234378146, [email protected] bICEMS, Instituto Superior Técnico, UTL, Av.Rovisco Pais, 1049-001 Lisboa, Portugal

Zinc is an important metal in materials science being used in galvanizing of steel, as anode in cathodic protection of iron and steel, in batteries, brass metallurgy, in protective coatings and as catalyst. The main drawback of zinc for some applications is the localized corrosion occurrence. Metallic corrosion takes place in different forms, depending on the surrounding medium. Some important parameters are pH, oxygen content, medium resistivity, temperature and presence of aggressive or inhibitive species. To fully describe the corrosion mechanism in confined places it is necessary to know the local distribution in solution of the chemical species that are important for the process. In this case miniaturized ion-selective electrodes can be of great value. In this work the corrosion of pure zinc immersed in NaCl was characterized experimentally using Zn2+ and pH potentiometric microelectrodes. The microelectrodes were prepared from single-barrelled glass capillaries with tip diameter of 2 µm and contain neutral carrier based cocktail as sensitive membrane. Values of corrosion potential (E), pH and pZn (-logaZn2+) were obtained in selected places of the corroding sample. An interpretation of the local chemical environment can be done by Geochemical Modeling Software. The stability and Pourbaix diagrams presented were generated by the Medusa and Hydra [1] software for different Zn2+ concentrations. Experimental data (E, pH and pZn) were added to the diagrams enabling the comparison between theory and experiment. At the limit, valid models will allow predicting corrosion and its mitigation without the need of experimental work. References: [1] http://www.kemi.kth.se/medusa/. Keywords: Corrosion, microsensors, chemical speciation, modeling.


17

P2

Bio-functionalisation of nanostructured gold surfaces by in-situ dithiocarbamate formation

Inês Almeida and Ana S. Viana

Centro de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Ed. C8,

Campo Grande, 1749-016 Lisboa, Portugal

It has been demonstrated that the combination of nanomaterials and biomolecules is of great interest in the area of biosensors. Nanoparticles (NPs) can have a decisive role in the immobilization of biomolecules due to their large surface area, great biocompatibility and conductivity. The use of NPs in the field of biosensors has become far investigated, revealing that AuNPs modified with enzymes exhibit excellent catalytic effects in many chemical reactions [1]. In the last years the in-situ formation of dithiocarbamates (DTC) on gold, through the reaction between carbon disulphide and secondary amines, with a bidentate N-C-S2 resonance structure, has been investigated and considered as a good alternative to thiolated SAMs [2]. When conjugated with AuNPs, DTCs revealed promising optical and electronic properties [3]. Very recently, we have described [4] that a simple one-step method in the presence of CS2 could be used for the direct immobilisation of Glucose Oxidase, from aqueous medium, with the preservation of its biological activity.

The purpose of this work is the bio-functionalisation of AuNPs through the one-step reaction between CS2 and amines (using epinephrine as a model electroactive compound and Glucose Oxidase which contains several amine groups in its structure) with the formation of DTCs/AuNPs, followed by their immobilization onto flat gold electrodes. The redox behaviour of modified gold with secondary amine (epinephrine) confirms its covalent immobilization as well as an increase of its amount on the electrode due to the presence of AuNPs. The reaction of CS2, Glucose oxidase and AuNPs has been also attested by electrochemical assays, indicating that direct electron transfer reaction can be occurring between the enzyme active centre and the electrode surface. The characterization of modified Au-NPs in colloidal suspension and onto flat gold electrodes is performed by electrochemical techniques (cyclic voltammetry), spectrophotometric (UV-Vis spectroscopy) and microscopic, Atomic Force Microscopy (AFM). Keywords: Dithiocarbamate, Glucose Oxidase, Gold Nanoparticle, Biosensing Acknowledgements The authors acknowledge V. Ferreira for the synthesis of gold nanoparticles and Fundação para a Ciência e a Tecnologia for funding (PTDC/QUI/66612/2006). References [1] B. Zheng, S.Xie, L. Qian, H. Yuan, D. Xiao, M. M. F. Choi, Sensors and Actuators B (2010) doi:10.1016/j.snb.2010.09.051 [2] Zhu H.; Coleman D. M.; Dehen C. J.; Geisler I. M.; Zemlyanov D.; Chmielewski J.; Simpson G. J.; Wei A. Langmuir 24 (2008) 8660 [3] Li M., Gao F.; Yang P.; Wang L.; Fang B. Surf. Sci., 2008,602, 151 [4] I. Almeida, A. C. Cascalheira, A. S. Viana, Electrochimica Acta 55 (2010) 8686


18

P3

Electrochemical Double Layer at the Hg/Choline Chloride Based Ionic Liquids Interfaces

Renata Costa, Carlos M. Pereira, Fernando Silva

Departamento de Química da Faculdade de Ciências da Universidade do Porto

Rua do Campo Alegre 687, 4169-007 Porto, Portugal

*[email protected] The electrochemical interfaces of several deep eutectic solvents based on choline chloride mixtures with 1,2 – ethanediol, 1,2 – propanediol, 1,3 – propanediol, urea and thiourea, and mixtures of acetylcholine chloride with urea were studied at a Hg electrode. The cyclic voltammetric results identified the potential domains of electrochemical stability and illustrated their dependence on the deep eutectic solvents composition. The differential capacitance – potentials, C(E), curves for the electrical double layer were obtained from electrochemical impedance data by adjusting the appropriate equivalent circuits. The structure of the interfaces is proposed to be dominated by adsorption of choline cations at large negative polarizations while at less negative or positive polarizations the structure is controlled by the adsorption of the anion. The temperature coefficients of the differential capacitance were found to be nearly zero. Acknowledgments: Work carried out under contract IONMET NMP2-CT-2005-515743 and Renata Costa acknowledge FCT for a PhD scholarship SFRH/BD/45462/2008 Keywords: Deep Eutectic Solvents, Choline Chloride, Double layer, Ionic Liquids.


19

P4

Corrosion and tribocorrosion behaviour of age-hardened Al-SiCp composites with a functional gradient of particles

A.C. Vieira(1), S. Mischler(2), A.M. Pinto(3), L.A. Rocha(4)

(1)CT2M – Centre for Mechanics and Materials Technologies; Mechanical Engineering Department (DEM) - University of Minho. Campus de Azurem, 4800-058 Guimarães –

Portugal. Tel: +351 253 510 220 ; Fax: +351 253 516 007; email: [email protected]

(2)Laboratoire de Métallurgie Chimique, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland; email: [email protected]

(3)CT2M – Centre for Mechanics and Materials Technologies; Mechanical Engineering Department (DEM) - University of Minho. Campus de Azurem, 4800-058 Guimarães –

Portugal. Tel: +351 253 510228; Fax: +351 253 516 007; email: [email protected] (4)CT2M – Centre for Mechanics and Materials Technologies; Mechanical Engineering Department (DEM) - University of Minho. Campus de Azurem, 4800-058 Guimarães –

Portugal. Tel: +351 253 510231; Fax: +351 253 516007; email: [email protected]

Al alloy matrix reinforced with SiC particles (Al-SiCp composites) has shown a great potential for several industries essentially due to their mechanical resistance. Additionally, by creating a gradual decrease of the amount of reinforcing particles from the surface to the bulk, it is possible to combine surface hardness and higher wear resistance with high bulk toughness [1,2]. Aging treatments can additionally increase the mechanical and tribological properties of Al-SiCp composites, especially in Cu-containing Al matrix [1,3]. Nevertheless, the presence of Cu has a detrimental effect on the corrosion resistance of these materials [4]. However, the behaviour of Cu-containing Al/SiCp composites when sliding occurs in the presence of a corrosive environment is not known. Furthermore there is a lack of information about the influence of age-hardening on the tribocorrosion behaviour of Al-SiCp. This phenomenon can have important practical relevance in different industrial sectors. The main aim of this work was to investigate the effect of different aging-hardening conditions on the corrosion and tribocorrosion behaviour of Al-SiCp functionally graded composites. A home-developed Al-10Si-4.5Cu-2Mg was selected as matrix and SiC particles were used as reinforcement. Post-processing age-hardening treatments were done. The solution treatment was made at 500 °C (2h and 8h as holding time) followed by quenching and artificial aging (thermostatic silicone bath at 160 °C, during 512min). The corrosion and tribocorrosion tests were made in 0.05M NaCl and 0.1M NaNO3 solutions, at 25°C. The tribocorrosion tests were performed in a reciprocating ball-on-plate tribometer and the friction coefficients as well as relevant electrochemical parameters (OCP) were monitored during the tests. It was demonstrated that the tribocorrosion behaviour is dependent on the corrosion mechanisms and on SiC distribution.


20

P5

Corrosion rate monitoring of steel in reinforced concrete structures:

comparison between external and embedded sensors

E. V. Pereiraa, M. M. Saltab, I. T. E. Fonsecac

a, b Laboratório Nacional de Engenharia Civil, Av. do Brasil, 101, 1700-066 LISBOA (Portugal), [email protected], [email protected]

c CCMM, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Edifício C8, 1749-016 LISBOA (Portugal), [email protected]

It is well known that steel passivation in concrete is due to the highly alkaline environment (pH: 12.5 to 13.6). However, steel passivity can be destroyed by local acidification, carbonation, ingress of chloride ions and/or depletion of O2, being the corrosion of reinforcements one of the major causes of the degradation of concrete structures in aggressive environments.

In order to assist the development of reliable models that allow the design of new structures durable in aggressive environments and to establish rational maintenance and repair strategies of reinforced concrete structures affected by reinforcement corrosion, various systems for permanently monitoring the corrosion on site have been developed.

In spite of the extended laboratory experience in the measurement of the corrosion rate of steel in concrete few results have been reported in measurements in situ. Two main electrochemical techniques have been proposed to on site measurement the corrosion rate of reinforcing steel, one using external sensors applied on concrete surface and using sensors embedded in concrete during concreting.

In the present work results from corrosion rate monitoring in reinforced concrete slabs exposed to natural environmental conditions will be reported. Corrosion currents, icorr, estimated from the polarization resistance, Rp, were measured directly on reinforcement, by means of external probes with guard ring (GEOCOR 06), and in internal sensors specially designed to be embedded in different depths in the concrete cover. Two concrete compositions were studied in different conditions of corrosion initiation, one due to the introduction of chlorides during concrete mixture and other due to external chloride penetration.

From this study it could be concluded that the designed embedded icorr sensor allows distinguishing between the active and passive corrosion state of steel in concrete and detects the beginning of steel corrosion induced by chlorides. It is also sensitive to the natural environmental variation of the corrosion rate. Results obtained with external probes did not allow to distinguish between the passive and active state of steel in the higher resistive concrete (water-to-cement ratio of 0.5). Acknowledgments: I. Fonseca acknowledges FCT (Fundação para a Ciência e Tecnologia) for providing financial support to CCMM (Centro de Ciências Moleculares e Materiais). Keywords: embedded sensors, reinforcing steel corrosion rate, monitoring


21

P6

Electrochemical study of (ηηηη6-cymene)ruthenium(II) complexes bearing bis-,

tris- and tetrakis(pyrazol-1-yl)borate ligands Luísa M.D.R.S. Martinsa,b, Claudio Pettinaric, Fabio Marchettid, Adele Cerquetellad, Riccardo

Pettinaric, Magda Monarie, Tatiana C.O. Mac Leodb, Armando J.L. Pombeirob

aÁrea Departamental de Engenharia Química, ISEL, R. Conselheiro Emídio Navarro, 1959-

007 Lisboa, Portugal. e-mail: [email protected] bCentro de Química Estrutural, Complexo I, IST, Av. Rovisco Pais, 1049-001 Lisboa,

Portugal cSchool of Pharmacy, University of Camerino,Via S. Agostino 1, 62032 Camerino, Italy

dSchool of Science & Technology, University of Camerino, Via S. Agostino 1, 62032 Camerino, Italy

e Dipartimento di Chimica “G. Ciamician” Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy

[Ru(η6-arene)(chelating-ligand)Cl] type-complexes exhibit the characteristic “piano stool” structure, with the unreactive arene as a “spectator ligand” in the coordination sphere of the metal and the chloride as a suitable “leaving group” which accounts for their potential as catalysts for a number of organic reactions. The study we now report aimed at a systematic investigation of the interaction between (p-cymene)ruthenium(II) and the bis-, tris- and tetrakis(pyrazolyl)borates Ph2Bp, Tp, Tp4Bo, Tp4Bo,5Me, TpBn,4Ph and pzTp (Ph2Bp = diphenylbis(pyrazol-1-yl)borate; Tp = hydrotris(pyrazol-1-yl)borate; pzTp = tetrakis(pyrazol-1-yl)borate; Tp4Bo = hydrotris(indazol-1-yl)borate, Tp4Bo,5Me = hydrotris(5-methyl-indazol-1-yl)borate; TpBn,4Ph = hydrotris(3-benzyl-4-phenylpyrazol-1yl)borate), as well as the electrochemical behaviour of the resulting complexes. The redox properties of our compounds have been investigated by cyclic voltammetry at a Pt electrode, in a 0.2 M [nBu4N][BF4]/CH2Cl2 solution, at 25oC. They exhibit a single-electron oxidation assigned to the RuII

→ RuIII oxidation, at the oxidation potential values in the 0.93 - 1.36 range and at ca. 1.8 V vs. SCE for the neutral and cationic ones, respectively. The compounds also show irreversible reduction waves in the -1.2 to -1.5 V range which can involve the poly(pyrazolyl)borate ligands. The values of the RuII/III oxidation potential of our complexes reflect the electron-donor properties of their ligands and allowed us to estimate the values of the electrochemical ligand parameter EL for the Tp and related ligands of these complexes which can be ordered as follows according to their electron-donor character: tris(pyrazolyl)methanesulfonate, SO3Cpz3

- (EL = -0.09 V vs. NHE) > pzTp- > Tp- ≈ (Tp4Bo,5Me)- > hydrotris(pyrazolyl)methane, HCpz3 (EL = 0.14 V vs. NHE) > (Tp4Bo)- ≈ 4-methylpyrazole (EL = 0.18 V vs. NHE). Acknowledgements:This work has been partially supported by the Foundation for Science and Technology (FCT) (grant BPD/46812/2008) and its PPCT program (FEDER funded). Keywords: Cyclic Voltammetry, Electrochemical Parameters, Ruthenium(II), Poly(pyrazolyl)borates.


22

P7

Voltammetric Quantification of Catecholamines

I. M. Mirandaa, M. Araújoa, F. Silvaa, C. M. Pereiraa*

a) Departamento de Química da Faculdade de Ciências da Universidade do Porto

Rua do Campo Alegre 687, 4169-007 Porto, Portugal

*[email protected] Catecholamines (CAT) play an important role in living organisms where they act as neurotransmitters. Their in vivo monitorization is very important because their endogenic levels are affected in case of some degenerative diseases like Alzheimer and Parkinson.1 The electrochemical determination of catecholamines in vivo2, in particular Dopamine, Epinephrine and Noradrenaline, are still subjected to interferences and low sensitivity is usually obtained. To improve their measurements we are trying to modify a GC electrode3 with gold nanoparticles and study the sensitivity obtained for the working electrode with and without surface modification. We found that electrode modification allowed an importante decrease of mininum quantity possible to measure by SWV and the increase of peak current intensity. The calibration plots obtained also show, for modified electrodes, a bigger slope in linear range and the beginning of a non-linear profile for concentrations of catecholamines bigger than 1,0 x 10-4 M. Keywords: catecholamines, SWV, GC electrodes, nanoparticles. Bibliography 1. E. Wołyniec, M. Wysocka, M. Pruszynski, A. Kojło, Instrumentation Science and Technology, 35 (2007) 241–253. 2. F. Xu, M. Gao, L. Wang, G. Shi, W. Zhang, L. Jin, J. Jin, Talanta, 55 (2001) 329–336. 3. G. Hu, D. Zhang, W. Wu, Z. Yang, Colloids and Surfaces B: Biointerfaces, 62 (2008) 199-205


23

P8

Electrochemical Study Of Ammonium Ion Transfer At An Interface Between Two Immiscible Electrolyte Solutions

J.A. Ribeiroa, C.M. Pereiraa, F. Silvaa

a Centro de Investigação em Química – Linha 4

Departamento de Química e Bioquímica Faculdade de Ciências da Universidade do Porto

Rua do Campo Alegre 687, 4169-007 Porto – Portugal [email protected]

Determination of ammonia or ammonium ion is important in clinical1, environmental2 and industrial3 process analyses. Furthermore, measurement of ammonium ions in biosensors has found an increasing application because ammonium ions are a metabolic product in many enzymatic reactions (for example, urea can be detected by sensing its metabolic product, i.e. ammonium ions4).Therefore, highly sensitive and selective methods are required for their determination. The study of NH4

+ at the interface between two immiscible electrolytes solutions (ITIES) were previously reported5-9, however there is no reference of studies from the analytical point of view. In this work, we report the electrochemical characterization and quantification of ammonium ions transfer across the water/1,6-dichlorohexane interface. Voltammetric techniques (cyclic voltammetry, differential pulse voltammetry and square wave voltammetry) were used to study the interfacial and transfer properties of the ammonium ions. The analytical performances were assessed, including the slope, the intercept of the linear fitting, the linear range of concentrations and the limit of detection (LOD). References: 1 J.M.C.S. Magalhães, A.A.S.C. Machado, Analyst 127 (2002) 1069. 2 H.S. Twu, T.R. Ling, T.C. Chou, M.C. Yang, Ultrason. Sonochem. 8 (2001) 41. 3 T. Suzuki, T. Yasuda, T. Yamane, S. Shimizu, J. Ferment. Technol. 64 (1986) 63. 4 S.S.M. Hassan, S.A. Marei, I.H. Badr, H.A. Arida, Anal. Chim. Acta 427 (2001) 21. 5 T. Osakai, T. Kakutani, M. Senda, Anal. Sci. 3 (1987) 521. 6 Z. Yoshida, S. Kihara, J. Electroanal. Chem. 227 (1987) 171. 7 N.K. Harris, S. Jin, G.J. Moody, J.D.R. Thomas, Anal. Sci. 8 (1992) 545. 8 H.J. Lee, C. Beriet, H.H. Girault, J. Electroanal. Chem. 453 (1998) 211. 9 B. Su, S. Zhang, Y. Yuan, J. Guo, L. Gan, Y. Shao, Anal. Chem. 74 (2002) 373. Acknowledgments: J.A. Ribeiro acknowledges FCT for a PhD grant SFRH/BD/45492/2008. Keywords: ammonium ion; ITIES; water/1,6-dichlorohexane interface; cyclic voltammetry.


24

P9

Influence of the Substrate on the Self-assembly of Phosphonic Acids

Monolayers

Joana Cabritaa,b, Franz-Peter Montfortsb, Luisa Maria Abrantesa, Ana S. Vianaa

a CQB, DQB, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal, luisa.abrantes@ fc.ul.pt

b Institut für Organische Chemie, FB 2 Biologie, Chemie der Universität Bremen, Postfach 330440, Bremen D-28334, Germany

Phosphonic acid molecules have been self-assembled onto a variety of metal oxides displaying structural and chemical properties close to those of thiol/gold monolayers, with application in distinct areas, namely surface protection [1] and biosensing [2]. The chemical nature of the substrates [3], the presence of different oxide layers obtained from electrochemical pre-treatment [4] and surface morphology are known to influence the self-assembling process of the organophosphonic molecules.

In this work, the influence of the substrate nature and the presence of oxides/hydroxyl species on the spontaneous adsorption of Co-Porphyrin-PO3 and decane-phosphonic acid (C10H23PO3) from butanol solutions was evaluated. Gold, platinum and highly ordered pyrolytic graphite (HOPG) electrodes were used, and submitted to different pre-treatments in order to control their surface properties, prior to organic compounds self-assemblage. Electrochemical reductive desorption studies have shown that monolayers of both phosphonic acid derivatives could be prepared on the different electrode surfaces, although exhibiting dissimilar voltammetric responses as a consequence of the type of substrate in use. The redox behaviour of Co-Porphyrin monolayers in organic medium when compared to that of Co-Porph-CO2CH3 precursor in solution, attested the spontaneous immobilization of these molecules. The surfaces hydrophilicity/hydrophobicity were analysed by contact angle measurements, further confirming substrate modification and indicating that metalloporphyrin adsorption induces more hydrophilic surfaces than the decane-phosphonate molecules.

Keywords: Self-Assembled Monolayers, Decane- and Cobalt-Porphyrin Phosphonic Acids, Gold, Platinum, Highly Ordered Pyrolytic Graphite. Acknowledgments J. F. Cabrita acknowledges the PhD scholarship SFRH/BD/47703/2008 (Fundação para a Ciência e Tecnologia). References [1] C.L. Perkins, J. Phys. Chem. C, 113 (2009), 18276. [2] Wei Luo, Nathan P. Westcott, Abigail Pulsipher, and Muhammad N. Yousaf, Langmuir, 24 (2008)13096. [3] P.B. Paramonov, S.A. Paniagua, P.J. Hotchkiss, S.C. Jones, N.R. Armstrong, S.R. Marder, J.-L. Brédas, Chem. Mater., 20 (2008) 5131. [4] J.F. Cabrita, A.S. Viana, L.M. Abrantes, Corros. Prot. Mater., 29 (2010) 114.


25

P10

Formation of ternary lipid bilayers with phase separation on gold

Joaquim T. Marquês, Rodrigo F.M. de Almeida Ana S. Viana,

CQB, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Ed. C8, 1749-016 Lisboa, Portugal

Supported lipid bilayers (SLBs) are very useful model systems to investigate the properties of biomembranes and their interaction with other biomolecules, such as proteins [1]. In addition, the ability to produce SLBs on gold, a conductive substrate, also has important applications to design lipid-based biosensor interfaces. However, due to its hydrophobic properties, most experiments involving SLBs on gold require a previous metal surface modification, either by a self-assembled monolayer, a polymer cushion, or the use of tethered lipids [2]. Moreover, most of those studies are not carried out in ternary lipid mixtures containing cholesterol, which were established in the past decade as the suitable model for the lipid rafts that are present in the plasma membrane of mammalian cells [3]. Thus, the goal of the present work was twofold. First, we sought for experimental conditions that allow the formation of stable and organized SLBs directly on bare gold. Moreover, we used the ternary lipid mixture 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)/cholesterol (4:4:2) in order to study lipid raft organization. The topography of the SLBs, as assessed by in situ Atomic Force Microscopy, reveals that with high saline concentrations (usual for SLB formation on mica) the fusion of vesicles is incomplete, leading to the formation of tubular structures. However, in the absence of salt, planar and well organized SLBs are consistently obtained, either from small unilamellar vesicles (SUVs) or large unilamellar vesicles (LUVs). Lipid domains differing ~1.5 nm in thickness ascribed to the presence of lipid rafts were clearly observed. In addition, from ellipsometric measurements, estimated average thicknesses of bilayers derived from SUVs and LUVs were ~4 nm and ~6 nm, respectively, suggesting that this latter bilayer covers a larger fraction of the substrate surface. This behavior is confirmed when the blocking effect of these SLBs to K3[Fe(CN)6] is assessed by cyclic voltammetry, where a lower current intensity for the redox process is obtained for the sample made from LUVs. Hence, LUVs and a buffer with no added salt at pH 7.4 are suitable for the preparation of stable ternary SLB directly on bare gold. Keywords: Supported Lipid Bilayers, Gold surfaces, in-situ Atomic Force Microsccopy, Cyclic Voltammetry, ellipsometry. Acknowledgements A.S.V. and R.F.M.D. acknowledge funding from F.C.T., Portugal, received through the Centre of Chemistry and Biochemistry and research grant PTDC/QUI/66612/2006. J.T.M. acknowledges PhD scholarship FRH/BD/64442/2009. References [1] Marquês, J. T.; Viana A. S.; De Almeida, R.F.M.; BBA - Biomembranes, 1808, 1, 405-414, 2011. [2] Reimhult, E. and Kumar, K.; Trends in Biotechnology, 26, 2, 82-89, 2008. [3]De Almeida, R.F.M.; Loura, L.M.S.; Prieto, M.; Chemistry and Physics of Lipids, 157, 2, 61-77, 2009.


26

P11

Modified titanate nanotubular structures for electrochemical applications

O. C. Monteiroa, N. Itob

aCentre of Chemistry and Biochemistry (CQB), Department of Chemistry and Biochemistry,

Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016 Lisbon, Portugal; bGraduate School of Environmental Studies, Tohoku University, 6-6-20, Aoba, Aramaki,

Aoba-ku, Sendai, 980-8579 Japan

At present, the synthesis, combination and manipulation in a nanoscale level allows the control over materials intrinsic properties. Titanate nanotubes (TNTs) combining the properties of conventional TiO2 (e.g., wide-bandgap semiconductor, photocatalysis) with the properties of layered titanates (e.g., ion-exchange ability), have recently received attention due to their wide potential applications, including biosensors fabrication and electrocatalysis. The high cation-exchange character of protonated titanate nanotubes (H2Ti3O7) as well as the particular tubular structure makes them very suitable to act as the substrate and carrier for different materials, for example catalysts, that need to be immobilized. For instance, on the catalytic research area, the combination of metal ions with TNTs can result in materials with improved catalytic performances. The aim of this work is the synthesis and characterization of cobalt modified TNTs with enhanced electrocatalytic activity. Two distinct modified tubular nanostructures, type MxHyTi3O7 were obtained by using two different approaches: by a proton-metal ion replacement process and by an in situ metal doping, e.g, during the TNTs hydrothermal synthesis. The cobalt influence on the TNTs structure and chemical composition is studied and is presented. In order to evaluate the prepared materials potentialities for electrochemical applications and, considering the presence of the cobalt ions on different TNTs structural positions, the electrochemical characterization of the prepared materials is carried out and discussed.


27

P12

Voltammetric Study of Copper Species Immobilized on

Multi-Walled Carbon Nanotubes Film-Coated Electrode

Jorge Ginja Teixeiraa,d, Alfredina Veigaa,d, José Mirãob,d, António Candeiasa,d,e,

D. Martins Teixeirac,d aUniversity of Évora, Chemistry Department and Chemistry Center of Évora (CQE), Tel: 351

266745304, Fax: 351 266744971; mail: [email protected] bUniversity of Évora, Geosciences Department and Geophysics Center of Évora (CGE)

cUniversity of Évora, Chemistry Department and Institute of Mediterranean Agric. and Environmental Sciences (ICAAM)

(Rua Romão Ramalho, 59, 7000-671 Évora, Portugal) dHERCULES Laboratory, University of Évora, Palácio do Vimioso

Largo Marquês de Marialva, 8, 7000-809 Évora, Portugal eInstitute of Museums and Conservation, José de Figueiredo Laboratory

Rua das Janelas Verdes, 37, 1249-018 Lisboa, Portugal ([email protected]) Over the last two decades, it has been demonstrated that the importance of the electrochemical methods in the field of archaeometry, conservation and restoration of cultural heritage has been significantly increased [1, 2]. This fact has been related, mainly, with the development and application of new methodologies, such as the voltammetry of microparticles [3]. This is based on the voltammetric response of solid microsamples immobilized on the surface of suitable working electrodes, when in contact with an electrolytic solution [1-3]. Through this methodology and making use of a limited kind of working electrodes, such as the paraffin impregnated graphite electrode, the carbon paste electrode and others, it is possible to obtain information about the chemical composition and distribution of electroactive species that comprise the archaeological solid samples [1-3]. In this context, we propose the innovative application of a multi-walled carbon nanotubes film-coated electrode, as an alternative immobilization support for the voltammetric study of these samples. To demonstrate the usefulness of this electrode, we carried out a cyclic voltammetric study, with solid microsamples (natural and artificial) that contains different chemical forms of copper (Cu(0), Cu(I) and Cu(II)), in different coordination environments. With this study, we aim to investigate the conditions under which this electrode can be used, to get information about the chemical composition (i.e., redox and mineralogical speciation [2]) of corrosion products of ancient copper artefacts. [1] A. Doménech-Carbó, M.T. Doménech-Carbó, V. Costa, Electrochemical Methods in Archaeometry, Conservation and Restoration, in Monographs in Electrochemistry, F. Scholz (Ed.), Springer-Verlag, Berlin Heidelberg, 2009. [2] A. Doménech-Carbó, J. Solid State Electrochem., 14 (2010) 363–379. [3] F. Scholz, U. Schroder, R. Gulaboski, Electrochemistry of Immobilized Particles and Droplets, Springer-Verlag Berlin Heidelberg, 2005. Keywords: voltammetry of microparticles; copper speciation; multi-walled carbon nanotubes film-coated electrode; archaeometry.


28

P13

Mediated catalytic electrochemistry of Pseudomonas stutzeri cytochrome c

peroxidase: insights into the activation mechanism

P. M. Paes de Sousaa, D. Rodriguesa, C. G. Timóteoa, M. L. Simões Gonçalvesb, G. W. Pettigrewc, I. Mouraa, J. J. G. Mouraa, M. M. Correia dos Santosb

aReQuimte, CQFB, Dept. Química, FCT, UNL, 2829-516 Caparica, Portugal

bCQE, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal cRoyal (Dick) School of Veterinary Studies, UE, Edinburgh EH9 1QH, Scotland, UK

Bacterial cytochrome c peroxidases (CCPs) are dihaem proteins that catalyse the reduction of hydrogen peroxide to water, delivering two electrons from a single small redox protein. Most of these enzymes are isolated in a resting state and an activation mechanism is required for the catalytic reaction to occur [1].

In the resting oxidised state, one of the haems is in a low-spin/high-spin thermal equilibrium, has a high redox potential reflecting a His-Met coordination and is believed to function as the electron-transferring (E) haem. The second haem (P), with a low redox potential and a low-spin bis-His coordination in the oxidised state, is thought to be the catalytic centre where H2O2 is reduced to water. In the activation mechanism, reduction of the E haem induces a series of complex spin state and coordination changes, producing a mixed-valence enzyme in which the P haem has become high-spin pentacoordinated, providing access to the substrate.

It is known that calcium ions are required for the conversion of the mixed valence enzyme into the activated state, but members of the bacterial CCP family vary in the affinity for these cations. Spectroscopic studies suggested that, in contrast with other CCPs, the enzyme from Pseudomonas stutzeri (Ps) is purified in a form with tightly bound Ca2+, and consequently is readily active upon reduction [2].

The activation mechanism of Ps CCP was probed through the mediated catalysis by its physiological donor, Ps cytochrome c551. The studies were performed by cyclic voltammetry using a pyrolytic graphite (PG) membrane electrode and without the addition of calcium ions. Similar intermolecular rate constants were estimated for the oxidised and mixed-valence forms of the enzyme, confirming that the activation mechanism of Ps CCP is fast. Direct electrochemistry was also attempted, but an altered form of the enzyme is induced by interaction with the PG surface, as observed for the Paracoccus pantotrophus CCP [3]. References: 1. GW Pettigrew, A Echalier, SR Pauleta, J Inorg Biochem, 2006, 100, 551 2. CG Timóteo, P Tavares, CF Goodhew, LC Duarte, K Jumel, FMF Gírio, S Harding, GW Pettigrew, I Moura, J Biol Inorg Chem, 2003, 8, 29 3. PM Paes de Sousa, SR Pauleta, ML Simões Gonçalves, GW Pettigrew, I Moura, JJG Moura, MM Correia dos Santos, J Biol Inorg Chem, in press (doi:10.1007/s00775-010-0717-z). Keywords: cytochrome c peroxidase; cytochrome c551; Pseudomonas stutzeri; mediated catalysis; activation mechanism.


29

P14

Distribution of chemical species in aqueous solution near coupled iron and

zinc electrodes

A.C. Bastosa, O.V.Karavaia, M.L. Zheludkevicha, M.G.S. Ferreiraa,b

aDECV/CICECO, Universidade de Aveiro, 3810 Aveiro, Portugal

bDEQB, Instituto Superior Técnico, UTL, Av. Rovisco Pais, 1049-001 Lisboa, Portugal The galvanic coupling between zinc and iron is of great technological importance. A significant amount of the steel currently in use is coated with a layer of metallic zinc. The role of the zinc layer is twofold: a passive one, as it represents a barrier to the environment, and an active one, by preventing steel corrosion when it becomes exposed in pores, defects or scratches. The active protection comes from the zinc ability to bring steel to potentials where it is thermodynamically stable, provided both metals are electrically connected and in contact with an electrolytic solution. This is the basis for the cathodic protection of large steel structures like naval ships, offshore constructions, bridges, pipelines and storage tanks, using sacrificial zinc anodes properly placed in selected points of the structures. The main reactions are the zinc oxidation (at the zinc layer or at the sacrificial zinc anodes) and the reduction of dissolved oxygen (at the steel surface), both processes occurring separated in space thus creating local changes in the solution composition. Models presently in use to place zinc anodes for optimal cathodic protection are based on the potential and current distribution in solution, overlooking the chemical nature of the charge carriers, the chemical composition of the solution that actually contacts the metal surfaces and the possible chemical interactions that may result in solution. In order to evaluate the need of this extra chemical information to reach accurate modelling, the galvanic corrosion of a zinc disk - iron disk couple in 5 mM NaCl was characterized using microelectrochemical techniques. The objective was to produce distribution maps of several species (e.g. Zn2+, Fe2+, pH, O2) together with the current and potential in solution between the two metals. pH and pZn (-log aZn2+) maps were obtained with ion-selective microelectrodes and maps of Fe2+ and dissolved O2 were generated with data acquired with amperometric microelectrodes. The current and potential in solution were measured with the Scanning Vibrating Electrode Technique (SVET). This information will be used to model the galvanic corrosion of the Zn-Fe couple and to check the need of more data other than potential and current in solution. The work will continue following two directions: i) Measurement of the same chemical species in electrochemical cells of different geometry and larger dimensions (up to real structures); ii) Use of these data as input for chemical speciation and geochemical modeling of the chemical transformations occurring in the vicinity of corroding surfaces. Keywords: Galvanic corrosion, microelectrodes, potentiometric microsensors, amperometric microsensors.


30

P15

Modeling corrosion behavior of conductive coatings based on EIS, SVET and LEIS experiments

Andreia Marques, Jean-Baptiste Jorcin , Alda Simões*

GECEA/ICEMS, Instituto Superior Técnico, Technical University of Lisbon, TULisbon,

Portugal (*) [email protected]

Coiled-coated steel sheet is of special interest for the automotive industry and in the past twenty years, the automotive manufacturers moved from plain steel to galvanized steel. A thin layer of zinc provides cathodic protection to steel, which greatly delays the time for perforating corrosion. Corrosion resistance is further improved when metallic and organic coatings are applied together. On the other hand, organic coatings decrease weldability and cause susceptibility to cut-edge corrosion. Weldability can be achieved in various ways, namely with the introduction of conductive particles, like zinc or graphite. This work aims at a better understanding of the corrosion mechanisms in conductive coatings. Studies were performed with focus on Electrochemical Impedance Spectroscopy as well as on spatially-resolved techniques, the Scanning Vibrating Electrode Technique (SVET) and Localized Electrochemical Impedance Spectroscopy (LEIS). Two epoxy-based primer formulations were chosen as an object of study, one with dispersed Zn-55% Al microscopic particles and the other with graphite particles. The coatings can be described by a matrix of polymer with a dispersed conducting phase in which there is particles at the surface, some of them in contact with the substrate. The barrier effect can thus be considered as existing over most of the surface, although leaving a few spots on the surface that conduct down to the substrate. Modelling of the systems is made by a classical equivalent electric circuit for zinc-rich coatings for the initial stages of immersion, whereas with time a more complex circuit is required. Mapping of the surface by SVET and by LEIS allow detection of active, anodic and cathodic sites, as well as the delamination areas. Acknowledgments: The research was funded under contract RFCS-CT-2008-00028. Keywords: coil-coatings, conductive coatings, equivalent circuit, EIS, LEIS.


31

P16

Electrochemical Characterization Of Anodic Treated Titanium Surfaces For Biomedical Applications

A.C.Alvesa, J.C.S.Fernandesb, L.A.Rochaa,c

aCT2M – Universidade do Minho - Portugal

bICEMS/DEQB – Instituto Superior Técnico - Portugal cDEM – Universidade do Minho - Portugal

Titanium is known as a biomaterial due to its biocompatibility and as well due to the protective and compact oxide layer (mainly TiO2) that is spontaneously formed. When used as a bone implant, cells will be in direct contact with this surface layer. Therefore, many studies have been focused on the assessment of surface treatments to form a more homogeneous and dense oxide layer well as to endow bioactivity. In fact, the biocompatibility of titanium depends on the surface characteristics, including chemical composition and the incorporation of calcium and phosphorus on the titanium oxide surface, with specific Ca/P ratios, is known to benefit this biocompatibility. When an anodic treatment is performed above the breakdown voltage, a multi-scaled and multi-layered porous surface is obtained. These pores are expected to further influence the osseointegration process. At the same time, using an anodic treatment it is possible that the Ca and P ions contained in the solution (rich in calcium and phosphorous) become trapped in the porous oxide layers that are formed during the treatment. The main aim of this work is to study the influence on the corrosion behaviour of pure titanium of the anodic treatment processing parameters, namely the electrolyte concentration. Different concentrations of calcium acetate in the electrolyte used for the anodic treatment were tested. It was observed that the concentration of calcium acetate has an important influence on the morphology and structure of the oxide film, namely an increase of the pores size with the increase of the calcium acetate concentration. Electrochemical impedance spectroscopy and potentiodynamic polarization were used in order to characterize the corrosion behaviour of the anodic oxide layers. It was found that the anodic treatment resulted in a strong improvement of the corrosion behavior, when compared with untreated titanium. However, anodic oxide layers with lowest Ca/P ratio presented the best corrosion behaviour. The corrosion mechanisms were studied in detail, and it was concluded that the morphology, composition and structure of the outer porous layer of the anodic film is determinant for the corrosion protection of the material. Keywords: titanium, biomaterial, anodic treatment, electrochemical impedance spectroscopy


32

P17

Exploring the behavior of nanostructured Ag catalyst on

ethanol electrooxidation

M. C. Oliveira

1 Departamento de Química /CQ-VR, Universidade de Trás-os-Montes e Alto Douro, 5001-

801 Vila Real, Portugal

Direct ethanol fuel cell (DEFC) is being widely investigated and considered as a possible

power source for electric vehicles and other portable applications in the near future. The

classical catalyst for ethanol electrooxidation has been Pt, Pd, Pt alloys and Pd alloys.

However, the high price and limited supply of Pt and Pd constitute major barriers to the

development of DEFCs.

It is known that bulk Ag does not show any activity towards the ethanol electrooxidation,

however the properties of metallic nanoparticles may differ significantly from their bulk-scale

counterpart. The present work aims to investigate the electrocatalytic activity of nanostructed

Ag catalyst towards the electrooxidation of ethanol in the alkaline medium. A simple wet-

chemical approach has been applied to prepare Ag nanostructures on stainless and carbon

support materials. The effect of the size particle and support material will be discussed.

The structure and morphology of the catalyst is characterized by SEM and XRD and its

catalytic activity is evaluated by cyclic voltammetry and chronoamperometry.

Keywords: DEFC, ethanol electrooxidation, Ag nanostructures.


33

P18

Biohybrids doped with potassium triflate with potential application in electrochromic devices

M. Fernandes1, R. Rego1, M. C. F. Oliveira1, R. A. Sá Ferreira 2, L. D. Carlos2, A.

Gonçalves3, E. Fortunato3, V. de Zea Bermudez1

1 Departamento de Química /CQ-VR, Universidade de Trás-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal

2 Departamento de Física e CICECO, Universidade de Aveiro, 3810-193 Aveiro, Portugal 3 Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT,

Universidade Nova de Lisboa, 2829-516 Caparica, Portugal Electrochromic devices have many application possibilities in chemical sensors, display devices, optical shutters, supercapacitors and rechargeable batteries, smart windows and mirrors because of the many advantages of open circuit properties, low power consumption and high coloration efficiency, etc. In the last decades the versatile sol-gel process has become a popular synthetic route for the fabrication of electrochromic devices (ECDs). In particular it has opened new opportunities for obtaining advanced, high quality transparent thin electrolyte films with adequate chemical and mechanical properties. Several sol-gel derived organic-inorganic hybrid materials [1], including Li+ conducting Class II organically modified silicate electrolytes (ormolytes) [2], have been proposed in this context. In view of their use as environmentally friendly ion conducting (IC) films for ECDs, we have synthesized via the sol-gel method novel di-urethane cross-linked poly(ε-caprolactone) (MW = 530 gmol-1)/siloxane biohybrids incorporating a wide range of potassium triflate concentration. Prototype ECDs have been constructed using a four layer-sandwich configuration comprising two outermost layers composed of transparent conducting oxide films, an EC film of tungsten oxide (WO3) and an IC active layer of selected K+-doped ormolyte samples. The average optical transmittance, color (or electrochromic) contrast (∆%T), optical density (OD) and device response time associated with the coloring/bleaching process have been determined. The time stability of the devices has been tested by chronoamperometry measurements. The bleaching/coloration kinetics have been quantified and the coloring efficiency η = OD/ Qd (where Qd is the injected/ejected electronic charge) has been calculated. [1] Functional Hybrid Materials, P. Gómez-Romero and C. Sanchez (Eds.), Wiley Interscience, New York, 2003 [2] (a) B. Orel, U. Opara Krašovec, U. Lavrečič Štangar, P. Judeinstein, J. Sol-Gel Sci. Tech. 11 (1998) 87; (b) V. de Zea Bermudez and M. M. Silva, In Polymer Electrolytes: Fundamentals and Applications, Chapter 5, D. Santos and C. Sequeira (Eds.), Woodhead Publishing Limited, Cambridge, 2010 Keywords: poly(ε-caprolactone), biohybrids, electrochromic devices.


34

P19

Zn, Sn and Zn-Sn electrodeposition from Deep Eutectic Solvents

N. Pereira, S. Salomé, Paula M. V. Fernandes, Carlos M. Pereira, Fernando Silva

Universidade do Porto Faculdade de Ciências

Departamento de Química Centro de Investigação em Química – Linha 4

Rua do Campo Alegre 687 -4169-007 Porto – Portugal

Metal depositions from ionic liquids have received great interest recently. Abbott and co-

workers have demonstrated the possibility of deposition of a number of pure metals from

choline chloride (ChCl) based mixtures usually called Deep Eutectic Solvents (DES). One

type of DES is those based on mixture of choline chloride with suitable hydrogen bond

donors molecules. In this work we describe the cyclic voltammetric studies for the deposition

of Sn, Zn and Sn-Zn alloys from three liquids: 1ChCl:2Ethylene glycol, 1ChCl:2Propylene

glycol and 1ChCl:2Urea. The studies were carried out on three electrodes materials GC, Pt

and mild steel. The distinct differences in the cyclic voltammograms will be discussed in

terms of double layer structures in each liquid.

Chronoamperommetry was used to study the mechanism and nucleation growth of the

deposits. The results of testing the j-t transients against nucleation and growth models will

show and interpreted in terms of the double layer properties and transport properties in each

liquid (Fig.1).

25

20

15

10

5

0

x10-3

100806040200x10

-3

-1.20 V jdl j3Diodz jdl3Diodz

Fig. 1 Comparison of an experimental current density transient (—) recorded during Sn deposition on glass carbon electrode and a theoretical transient (—) obtained by non-linear fit.

Keywords: Deep Eutectic Solvents, Nucleation and growth models, electrodeposition.

Acknowledgments: This work was supported by IONMET Project, EU contract NMP2-CT-2005-515743 and Polyzion Project, EU contract NMP-SL-2009-226655.


35

P20

Corrosion evaluation of WE 54 and AZ 31 magnesium alloys in physiological media

A. Fernandesa*, M.F. Montemora, J.C.S. Fernandesa

aICEMS, Instituto Superior Técnico, Technical University of Lisbon, Portugal

*[email protected] Biocompatible metallic materials represent the state of art for medical implants. After decades of developing strategies to minimize the corrosion of metallic biomaterials, there is actually an increasing interest in using an intentional corrodible alloy in a number of critical medical devices. A number of recent works have emphasized the use of magnesium alloys as a new class of bio-resorbable materials for orthopaedic implants. They combine multiple interesting and useful properties such as biocompatibility and osteoactive properties, low density, elastic modulus and compressive yield strength close to natural bones and the elimination of surgery for implant retrieval. However, some key issues still lack of a precise study and improvement by the corrosion engineering researchers. Problems such as in vivo resorption being too rapid, too localized and unpredictable; and the fact that Mg corrosion produces hydrogen gas which may accumulate adjacent to the implant in the body still need to be overcome. Concerning these issues, the aim of this initial stage of the work consists in the study of two different magnesium alloys (WE 54 and AZ 31) regarding their electrochemical behaviour. Particular attention was focused on the effect of specific ions present in physiological media and on the effect of temperature.


36

P21

The Effect of Deformation on the Corrosion Resistance of NiTi

J.C.S. Fernandesa,*, T.M. Silvaa,b and M.J. Carmezima,c

a ICEMS/DEQB, Instituto Superior Técnico, TULisbon, 1049-001 Lisboa, Portugal

b Mech. Eng. Dept., Instituto Superior de Eng. de Lisboa, 1959-007 Lisboa, Portugal c Mech. Eng. Dept., Inst. Politécnico de Setúbal, ESTSetúbal, 2914 Setúbal, Portugal

In recent years NiTi shape memory alloys have attracted considerable interest for biomedical applications due to its unique combination of shape memory effect and superelasticity with a biocompatibility comparable to that of Ti. The shape memory effect has been successfully used for many clinical applications in orthopaedics, orthodontic archwires, dental implants, scoliosis correction, vena cava filters and cardiovascular endoprostheses. However, due to the high nickel content of the alloy and as this element may induce allergic response, the material should present superior corrosion resistance in contact with body fluids. Although several studies have been performed, by this group and others, on the corrosion performance of Nitinol when in contact with physiological media, no information is available on the characterization of the material after being deformed. In fact, implants in the body are working under loading/unloading conditions, being deformed in the plastic regime but there is still little information on the behaviour of the alloy under mechanical stresses. The aim of the present work is then to assess the Nitinol corrosion performance after deformation. For that purpose, d.c. polarization, electrochemical impedance spectroscopy and capacitance measurements in physiological medium were performed on Nitinol samples submitted to various degrees of deformation. It was found out that deformation of NiTi has no negative effect on its corrosion behaviour. On the contrary, a less defective oxide film is formed upon deformation, which may explain the higher oxide resistance shown by the deformed materials. Acknowledgments: The authors thank the Portuguese Foundation for Science and Technology (FCT) for the support in the frame of projects PTDC/CTM/67500/2006 and PTDC/CTM/68160/2006.


37

P22

Electrochemical study of NiII, ZnII and CuII complexes bearing a sterically

hindered scorpionate ligand (TpmsPh)-

Luísa M.D.R.S. Martinsa,b, Bruno G.M. Rochab, Armando J.L. Pombeirob

aÁrea Departamental de Engenharia Química, ISEL, R. Conselheiro Emídio Navarro, 1959-007 Lisboa, Portugal. e-mail: [email protected]

bCentro de Química Estrutural, Complexo I, IST, Av. Rovisco Pais, 1049-001 Lisboa, Portugal

Recently we have initiated the study of the coordination chemistry of tris(pyrazolyl)methane (Tpm) ligands, as well as the synthesis of new Tpm derivatives (XCpzR

3). For instance, we found that pyrazolyl rings containing bulky substituents at the 3-position can tune the coordination behaviour towards different metal centres and that the carbon functionalised sulfonate derivative (SO3CpzR

3)- confers higher stability and hydrosolubility to the

corresponding complexes and exhibits a marked coordination flexibility.

The study we now report aimed at a systematic investigation of the ligation of the sterically hindered and water soluble tris(3-phenylpyrazolyl)methane sulfonate (TpmsPh)- to NiII, ZnII and CuII, as well as of the electrochemical behaviour of the resulting complexes of general formula [M(TpmsPh)L] (M = Zn or Ni; L = Cl or CF3SO3) and [Cu(TpmsPh)(Cl)(H2O)]. In the Cu complex, the scorpionate is not N,N,N-coordinated, as exhibited by the Ni or Zn complexes, but coordinates in a N2O mode involving the sulfonate moiety in the coordination to copper.

The redox properties of our compounds have been investigated by cyclic voltammetry and controlled potential electrolysis at a Pt electrode, in a 0.2 M [nBu4N][BF4]/CH2Cl2 solution, at room temperature. Their reduction behaviour allowed us to get an insight into the net electron-donor ability of the (TpmsPh)- and co-ligands, in the redox M(II)/M(I) or M(I)/M(0) (M = Ni, Cu or Zn) interplay, essential to account for their versatility as potential catalysts. Acknowledgements: This work has been partially supported by the Foundation for Science and Technology (FCT) and its PPCDT (FEDER funded) programme. Keywords: Cyclic Voltammetry, Scorpionates, Tris(pyrazolyl)methanesulfonates, Controlled Potential Electrolysis. [1] R. Wanke, P. Smoleński, M.F.C. Guedes da Silva, L.M.D.R.S. Martins, A.J.L. Pombeiro, Inorg. Chem., 2008, 47(21), 10158-10168. DOI: 10.1021/ic801254b.


38

P23

Conducting polymers prepared from Deep Eutectic Solvents

Paula M. V. Fernandes, Carlos M. Pereira and A. Fernando Silva

CIQ – L4, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto

Rua do Campo Alegre, 687 4169-007 Porto, Portugal

Conducting polymers (CPs) are organic materials often called "organic metal" that display

electrical, magnetic, electronic and optical properties similar to metals and have the

mechanical properties and low density of a polymer.1

These properties of CPs have prompted researches to use these materials to build energy-

storage devices including supercapacitors and batteries2 or anodes for fuel cells3, furthermore

they also can be used as sensors4 or for protection against corrosion, the photodegradation of

semiconductor electrodes in galvanic cells.5

Polyaniline (Pani) was synthesized electrochemically in a Glassy Carbon (GC) substrate. The

polymer was electrodeposited using a choline chloride and 1,2 - ethanediol mixture and was

characterized by cyclic voltammetry (CV).

The electrochemical measurements reveal that polymers show good adhesion on the GC

surface in contrast they do not show good stability. The use of deep eutectic mixtures in

electropolymerization studies seems to be a good alternative to aqueous solutions but it is

easy to accept that more systematic data is necessary to optimize the conditions of these

experiments.

Acknowledgments: This work was supported by Polyzion Project, EU contract NMP-SL-2009-226655. References:

1. Jennifer M. Pringle;, John Efthimiadis; Patrick C. Howlett; Jim Efthimiadis; Douglas R. MacFarlane; Adrian

B. Chaplin; Simon B. Hall; David L. Officer; Gordon G. Wallace; Maria Forsyth; Polymer; 2004; 45; 1447–

1453.

2. Graeme A. Snook; Adam S. Best; J. Mater. Chem.; 2009; 19; 4248– 4254.

3. Bijay P. Tripathi; Vinod K. Shahi; Polymer; 2010; 1– 117.

4. Ulrich Lange; Nataliya V. Roznyatovskaya; Vladimir M. Mirsky; Analytica Chimica Acta; 2008; 614; 1– 26.

5. Libuse Broazová Petr Holler; Jana Kovářová; Jaroslav Stejskal; Miroslava Trchová; Polymer degradation and

Stability; 2008; 93; 592 – 600.


39

P24

The usage of spent zeolite catalysts impregnated by monoethanolamine as corrosion protective additive to reinforced cement: catalyst modification

and EIS analysis of mild steel in aqueous media

Y. Morozova, A.S. Castelaa,b, A.P. Soares a, M.F. Montemor a

a ICEMS, Instituto Superior Técnico, Technical University of Lisbon. Av Rovisco Pais 1049-001 Lisboa

b Instituto Politécnico de Setúbal. Largo Defensores da República, 1, 2910-470 Setúbal The reinforcing steel in concrete is normally protected from corrosion by the formation of a passive film. However, the diffusion of aggressive species, such as chloride ions and carbon dioxide through concrete can breakdown the passive layer, initiating the corrosion process. Rebars corrosion has a strong impact on the durability and performance of reinforced concrete structures. One of the possible solutions is to use penetrative corrosion inhibitors (PCI’s). The corrosion behaviour of reinforcing steel in the presence of PCIs has been widely studied . However, the application of PCIs doesn’t ensure the total protection against corrosion. Most of the problems related with low effectiveness of the PCIs have been attributed to leaching and evaporation of the volatile components. Porous materials that can store inhibitors inside and release it slowly could be utilized to solve that problem. Certain types of zeolites are known to adsorb monoethanolamine (MEA). The idea of the current work is to study if spent zeolite catalysts could be used for storage of PCI’s followed by the application into cement. Thermal analysis (TG and DTG) was used to evaluate the amount of MEA adsorbed. Open circuit potential (OCP), Linear polarization (LP) and Electrochemical impedance spectroscopy (EIS) measurements were performed using a three-electrode arrangement, consisting of the working electrode (mild steel), the counter electrode (Pt) and the reference electrode (SCE). The frequency range was swept between 50kHz and 0.025mHz. The amplitude of the wave was 10mV (RMS) vs OCP. LP was performed using independent samples for catholic and anodic branch at potential scanning rate of 0.5mV/s until current density reached 10A/m2. All tests were carried at least twice, the results were averaged. Acknowledgments: The authors acknowledge the FCT funding through Project PTDC/ECM/105427/2008 Keywords: steel corrosion, zeolite, ethanolamine, EIS.


40

P25

Metal interaction with light expanded clay aggregates (LECA): real pH

conditions and its effect on the adsorption of lead, zinc and copper

Sofia Capeloa, Manuel Caianoa, José Paulo Pinheirob

aDepartamento de Paisagem, Ambiente e Ordenamento, Escola de Ciência e Tecnologia,

Universidade de Évora, Rua Romão Ramalho, 59, 7000-671 Évora, Portugal (phone: +351 266 745385; Fax +351 266 +351 266 745395;

e-mail: [email protected]) bIBB/CBME, Departamento de Química, Bioquímica e Farmácia, Faculdade de Ciências e

Tecnologia, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal

This work focuses on the adsorption of heavy metal ions, such as lead, zinc and

copper, on light expanded clay aggregates (LECA) using square wave voltammetry (SWV)

for its determination. The retention of the heavy metal cations follows the order of Pb2+ >

(Cu2+, Zn2+). LECA revealed to be an excellent sorbent for lead removal, for the

concentrations used (1 to 100 mg/l). An efficiency of about 100% extraction was observed for

all the metals, after 4 hours of contact time, for smaller concentrations (1 mg/L for lead and

zinc, and 5 mg/L for copper). The mixture of metals were completely removed for a

concentration of 1 mg/L, while lead was the only metal that continues to be removed for a

concentration of 10 mg/L.

Additionally LECA induces an increase of pH in the solution, presenting a significant

advantage in metal removal which is highly pH dependent.


41

P26

Voltammetric detection of Domoic Acid at a multiwalled carbon-nanotube

electrode

F. Bentoa, D. Geraldoa, R. Oliveiraa, C. Teixeiraa, E. González-Romerob aDepartamento de Química Universidade do Minho, 4710 Campus de Gualtar, Braga, Portugal, phone: +351253604399, fax: +351253604382, [email protected], [email protected] bDepartamento de Química Analítica y Alimentaria, Faculdade de Química, Universidad de Vigo, 36310 Vigo, Spain, phone +34986812240, fax: +34986812322; [email protected]

Domoic acid (DA) is a heterocyclic amino acid and a structural analogue of kainic acid and proline. In mammals, including humans, DA acts as a neurotoxin, causing loss of short-term memory, brain damage and, in severe cases, death. DA enters in the food chain via phytoplankton, which serves as food to marine organisms as crustaceans, anchovies and sardines. DA concentrations at the tissues of these marine species can reach high values as a result of bioaccumulation [1]. To protect consumers from amnesic shellfish poisoning (ASP), most countries have defined a regulatory limit for shellfish of 20 µg/g (20 ppm) in accordance with the recommendations of Inverson and Farah [1]. The standard AOAC method, based on high performance liquid chromatography (HPLC), provides good reproducibility, high precision and the analysis of its isomers, although it is rather time-consuming [2, 3]. Thus, there is a need for a fast, selective and sensitive method suitable for a rapid screening of DA. The enzyme-linked immunosorbent assay (ELISA) is the only one that can be used for this aim [3]. Following an affinity recognition process, an electrochemical immunosensor has been developed based on screen-printed electrodes (SPEs). The detection is performed by means of the alkaline phosphatase activity in competitive assays [4, 5]. The use of this immunossensor did not become widespread, probably due to the intrinsic drawbacks that are typical of immunoassays, namely the long incubation times, high costs of the antibodies and the difficulties associated to their regeneration. The direct electrochemical detection of DA is not reported in literature, probably, because it is not electroactive on the most common electrode materials, such as carbon, gold or platinum. In this work we present the preliminary results of the development of an electrochemical sensor based on the direct interaction between DA and a carbon SPE modified with graphitized carbon nanotubes. The voltammetric response of DA is controlled by its adsorption to the electrode surface. The concentrations range tested were in the range of ng/l.

Acknowledgements: The authors thank to Ana Gago Team (UVigo) for their kind help and DA gift

1. Inverson, F., Truelove, J., Nat Toxins 1994, 2, 334–339. 2. Pineiro, N.; Vaquero, E.; Leao, J. M.; Gago-Martinez, A.; Vazquez, J. A. Rodriguez, Chromatographia 2001, 53, S231-S235. 3. Kawatsu, K., Hamano, Y., Noguchi, T.,Toxin 1999, 37, 1579–1589. 4. Micheli, L., Radoi, A., Guarrina, R., Massaud, R., Bala, C., Moscone, D., Palleschi, G., Biosens Bioelectron 2004, 20 (2), 190-196. 5. Kreuzer, M. P., Pravda, M., O'Sullivan, C. K., Guilbault, G. G., Toxicon 2002, 40 (9), 1267-1274.

Keywords:.Domoic acid, Voltammetry, SPE


42

P27

Metal speciation in seawater: links to bioaccumulation in fish tissues

M. Díaz-de Alba, M. D. Galindo-Riaño*, M. García-Vargas

Department of Analytical Chemistry, Faculty of Sciences, University of Cádiz, Campus Río S. Pedro, 11510 Puerto Real, Cádiz, Spain.

*Corresponding author: [email protected], tel:+34956016362 Analysis of heavy metals at trace levels in natural waters and biological samples is very important in the field of environmental analysis due to their important roles in life.

Chromium is a major pollutant introduced into the environment from a variety of industrial wastewaters. Among the species of chromium there are two common oxidation states present in the environment, Cr(III), considered to be a trace element species essential for the proper functioning of living organisms, and Cr(VI), potentially a highly toxic and carcinogenic agent. On the other hand, nickel has become an important contaminant in aquatic environment since it is a toxic heavy metal and some of its compounds are carcinogenic. Cobalt is known to be essential at trace levels to man, animals and plants for metabolic processes. The determination of trace amounts of cobalt in biological and environmental samples plays an important role in the fields of environmental analysis, process control and medicine [1].

The aim of this work is to study the distribution of chromium, nickel and cobalt in different compartments of aquatic environment in the Algeciras Bay and to assess bioavailability and bioaccumulation on aquatic biota. For this purpose, concentrations of Ni and Cr were measured in tissues (gill, liver and muscle) of four fish species (Solea vulgaris, Scorpaena spp, Chelidonichthys lastovizia and Diplodus sargus, the first one with benthic behaviour and the rest of them with demersal behaviour) and the study of heavy metal speciation of water was carried out by differential pulse adsorptive cathodic stripping voltammetry. A modification of schemes of speciation [2, 3], based on metal fractionation to different pH, was applied to the study of Ni and Co distribution in water. Cr speciation was performed following Application Note V-82 instructions.

The inflluence of the industrial activities around the bay was detected with higher metal concentrantion than background levels for nickel and chromium with significant differences among sampling sites. In the same sense, the highest Ni and Cr levels were observed in gill tissues. The levels of Ni in liver were higher than the results obtained for muscle. The levels of Cr in muscle were higher than in liver. The Concentration factor (CF) and Enhacement ratio (ER) values were calculated evaluating the metal accumulated by the fish tissues relative to their environment. They allowed to qualify the state of the bay water and help to evaluate those factors affecting bioavailability comparing the influence of total and free and weakly complexed ionic species.

Keywords: metal, speciation, bioaccumulation, fish

[1] G. F. Nordberg, B. A. Fowler, M. Nordberg, L. T. Friberg, Handbook on the Toxicology of Metals, Academic Press, Amsterdam (2007) 487 – 507. [2] J.C. Fischer, R. Nganou, M. Wartel, Talanta 31 (1984) 1057–1061. [3] G.E. Batley, Aust. J. Mar. Freshw. Res. 38 (1987) 591–606. Acknowledgment: This work has been supported by the grant “Formación de Profesorado Universitario” from Minister of Education and Science for M. Díaz de Alba


43

P28

Lead speciation in seawater by AGNES and SSCP

M. Díaz-de Albaa; M. D. Galindo-Riañoa*; M. García-Vargasa and J. P. Pinheirob

a Department of Analytical Chemistry, Faculty of Sciences, University of Cádiz, Campus Río

S. Pedro, 11510 Puerto Real, Cádiz, Spain. b Department of Chemistry and Biochemistry, Faculty of Science and Technology, University

of Algarve, Campus Gambelas, 8005-139 Faro, Portugal. *Corresponding author: [email protected], tel:+34956016362

The release of different pollutants into environment has increased noticeably as a result of industrialization, and thereby, lowered the quality of the environment to alarming levels. Of such pollutants, heavy metals are the most important because of their non-biodegradability, with lead ions being among the most abundant, toxic and hazardous.

It is well-established that the total concentration of an element is a poor indicator of its reactivity, bioavailability or toxicity [1]. Therefore, there is a great interest on the development of new analytical methods to study the speciation of heavy metals in environmental samples.

Two recent electroanalytical techniques for the analysis of heavy metals have been applied simultaneously to study lead in spiked synthetic and real seawater: stripping chronopotentiometry at scanned deposition potential (SSCP) and absence of gradients and Nernstian equilibrium stripping (AGNES). The first one allows to the study of dynamic speciation while the later measures the free metal concentration.. Free metal concentrations were compared with the theoretical values predicted by the equilibrium speciation code MINTEQ. It was found that results obtained from AGNES and MINTEQ were in agreement for synthetic seawater at pH 2, 5, 6, 7 and 8.5, as well as for real seawater at pH 2, 5 and 6. However, the results obtained by AGNES for real seawater at pH 7 and 8.5 were smaller than the ones computed by MINTEQ. This is probably due to the effect of natural organic matter, present in seawater which is not taken into account in MINTEQ calculations. The SSCP stability parameter K’- values were similar in both synthetic and real samples to those calculated from the free metal concentration provided by AGNES, except at pH 7 and 8.5 for real seawater. In that sample the SSCP stability parameter K’ was much higher the one computed from the free metal obtained by AGNES. In these conditions the SSCP slope was flattened which is a clear indication of the presence of heterogeneous ligands, like natural organic matter in solution. In these complex systems SSCP is able to diagnose the presence of heterogeneous ligands while AGNES still measures the free bulk metal concentration allowing the determination of the apparent stability constant in the bulk.

Keywords: Lead, seawater, free metal, AGNES, SSCP

[1] A. Tessier, D.R. Turner, Eds. Metal Speciation and Bioavailability in Aquatic Systems; IUPAC Series on Analytical and Physical Chemistry of Environmental Systems; J. Buffle, H. P. van Leeuwen, Series Eds; Wiley, Chichester, UK, 1995, Vol. 3

[2] H.P. van Leeuwen, R. M. Town, Environ. Sci. Technnol. 37 (2003) 3945-3952.

Acknowledgment: This work has been supported by the grant “Formación de Profesorado Universitario” from Minister of Education and Science for M. Díaz de Alba


44

LIST OF AUTHORS

Author Comunication

A. Candeias P12 A. Cerquetella P6 A. Fernandes P20 A. Gonçalves P18 A. Marques P15 A. Schneider KN5 A. Simões P15 A. Veiga P12 A.A. Ferreira P1 A.C. Bastos P1, P14 A.C. Vieira P4 A.C.Alves P16 A.J.L. Pombeiro P6, P22 A.M. Pinto P4 A.P. Soares P24 A.S. Castela P24 A.S. Viana P2, P9, P10 B.G.M. Rocha P22 C. G. Timóteo P13 C. Parat, KN5 C. Pettinari P6 C. Teixeira P26 C.M. Pereira P3, P7, P8, P19, P23 C.M.A. Brett KN3 D. Aguilar KN5 D. Geraldo P26 D. M. Teixeira P12 D. Rodrigues P13 E. Companys PL3, KN5 E. Fortunato P18 E. González-Romero P26 E. V. Pereira P5 F. Bento P26 F. Marchetti P6 F. Silva P3, P7, P8, P19, P23 F.-P. Montforts P9 G. W. Pettigrew P13 H. Girault PL1 H. L. Gomes KN2 H.P. van Leeuwen PL2 I. Almeida P2 I. M. Miranda P7 I. Moura P13 I. T. E. Fonseca P5


45

J. Cabrita P9 J. Galceran PL3, KN4, KN5 J. J. G. Moura P13 J. Mirão P12 J. Puy PL3 J.A. Ribeiro P8 J.-B. Jorcin P15 J.C.S.Fernandes P16, P20, P21 J.G. Teixeira P12 J.P. Pinheiro KN4, KN6, P25, P28 J.T. Marquês P10 L. Authier KN5 L. D. Carlos P18 L. Rocha KN4 L.A. Rocha P4, P16 L.M. Abrantes P9 L.M.D.R.S. Martins P6, P22 M. Araújo P7 M. C. Oliveira P17, P18 M. Caiano P25 M. D. Galindo-Riaño P27, P28 M. Díaz-de Alba P27, P28 M. E. Ghica KN3 M. Fernandes P18 M. G. Almeida KN1 M. García-Vargas P27, P28 M. L. Simões Gonçalves P13 M. M. Barsan KN3 M. M. Correia dos Santos P13 M. M. Salta P5 M. Monari P6 M. Potin-Gautier KN5 M.F. Montemor P20, P24 M.G.S. Ferreira P1, P14 M.J. Carmezim P21 M.L. Zheludkevich P1, P14 N. Ito P11 N. Pereira P19 O. C. Monteiro P11 O.V. Karavai P1, P14 P. M. Paes de Sousa P13 P.M. V. Fernandes P19, P23 R. A. Sá Ferreira P18 R. Costa, P3 R. Oliveira P26 R. Pauliukaite KN3 R. Pettinari P6 R. Rego P18


46

R.F. Domingos KN6 R.F.M. de Almeida P10 S. Capelo P25 S. Mischler P4 S. Salomé P19 T.C.O. Mac Leod P6 T.M. Silva P21 V. de Zea Bermudez P18 Y. Morozov, P24


47

LIST OF PARTICIPANTS

Almeida Inês Bela

Borralho Faculdade de Ciências da Universidade de Lisboa

Lisboa [email protected]

Almeida Maria Gabriela

Faculdade de Ciências da Universidade Nova


Alves Alexandra Universidade do Minho

Guimarães [email protected]

Bastos Alexandre Universidade de Aveiro

Aveiro [email protected]

Cabrita Joana Faculdade de Ciências da Universidade de Lisboa


Capelo Sofia Universidade de Évora

Évora [email protected]

Correia Jorge Faculdade de Ciências da Universidade de Lisboa


Diaz de Alba Margarita Faculty of Sciences (University of Cádiz)

Cadiz [email protected]

Domingos Rute Isabel

Instituto Superior Técnico


Fernandes Ana Instituto Superior Técnico


Fernandes João Salvador

Instituto Superior Técnico


Fonseca Inês Faculdade de ciências da Univ de Lisboa,


Galceran Josep Universitat de Lleida Lleida [email protected] Galindo-Riaño

Mª Dolores

Faculty of Sciences (University of Cádiz)

Cadiz [email protected]

Geraldo Maria Dulce

Universidade do Minho

Braga [email protected]

Ghica Maria Emilia

DQ, FCT Universidade de Coimbra

Coimbra [email protected]

Girault Hubert EPFL Lausanne [email protected] Gomes Henrique

Leonel Universidade do Algarve

Faro [email protected]

Karavai Olga Universidade de Aveiro


Leeuwen Herman van

Wageningen University and Research Center

Wageningen [email protected]

Lobo Victor DQ, FCT Universidade de Coimbra


Lopes Maria Celeste

Centro de Neurociências e Biologia Celular


Marques Andreia Instituto Superior Técnico



48

Marquês Joaquim Trigo

Faculdade de Ciências da Universidade de Lisboa


Martins Luísa ISEL Lisboa [email protected] Miranda Inês Faculdade de

Ciências da Universidade do Porto

Porto *

Monteiro Olinda Faculdade de Ciências da Universidade de Lisboa


Morozov Yegor Instituto Superior Técnico


Mota Ana Maria Instituto Superior Técnico


Oliveira Maria Cristina

Universidade de Trás-os-Montes e Alto Douro

Vila Real [email protected]

Paes de Sousa

Patricia Faculdade de Ciências da Universidade Nova

Lisboa Patrí[email protected]

Parat Corinne Université de Pau et des Pays de l\'Adour

Pau [email protected]

Pereira Carlos Faculdade de Ciências da Universidade do Porto

Porto [email protected]

Pereira Nuno Faculdade de Ciências da Universidade do Porto


Pinheiro Jose Paulo

Universidade do Algarve

Faro [email protected]

Proença Luis ISCS Egas Moniz Almada [email protected] Puy Jaume Universitat de Lleida Lleida [email protected] Ribeiro José Faculdade de

Ciências da Universidade do Porto


Rocha Luciana Universidade de Aveiro


Simões Alda Instituto Superior Técnico


Teixeira Cecília Olaio


Braga [email protected]

Teixeira Jorge M.G.

Universidade de Évora

Évora [email protected]

Vaz Pereira Elsa LNEC Lisboa [email protected] Viana Ana

Silveira Faculdade de Ciências da Universidade de Lisboa


Vieira Ana Catarina


Guimarães [email protected]


49

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