concentrated salts in analytical chemistry can …asianalysis13.cmu.ac.th/files/pl1-pl8.pdf ·...

PL-1 39

ASIANALYSIS XIII 8–11 December 2016, Chiang Mai, THAILAND

Concentrated Salts in Analytical Chemistry – Can They Help?

Gary D. Christian*

Department of Chemistry, University of Washington, Seattle,WA USA 98195

E-mail: [email protected]

Concentrated salts can enable the titration of very weak bases, in both aqueous and nonaqueous

solvents. Arrhrenius1, in 1899, found that addition of NaCl to weak acids caused an increase in

their dissociation constants. Brönsted2 later determined this to be due to a decrease in activity

coefficients of the ions. Kolthoff3 in 1916 found that alkaline indicators are given an acid tint by

neutral salts. Harned4 in the 1920s measured the effects of concentrated salts on activity

coefficients of acids, and they increase above unity at high concentrations. I will present the use of

concentrated salts to enhance titration curves of weak bases in either aqueous or nonaqueous

solutions, and give evidence of mechanisms5. Bases with Kb values as small as 4x10-14 can be

titrated in acetone in the presence of 3M LiClO46. These effects may find use in FIA and other

systems.

Concentrated salts can enable separation of water miscible solvents from aqueous solutions. I will

present early work of separating acetone from water7, enabling solvent extraction of metal chelates

into acetone8, a most favourable solvent for flame atomic absorption measurements. The

mechanism of separation will be given. Salting-out Assisted Liquid-Liquid Solvent Extraction

(SALLE) has been known since 19149, but only in recent years has become increasingly popular.

Several reviews10, 11, 12 and applications will be presented. Solvents like acetonitrile may be salted

out, allowing extraction of polar solutes for chromatography analysis13.

Basic knowledge of the evolution of old to new literature is important for young investigators to

propose novel ideas.

References

[1] S. Arrhenius, “Change in the strength of weak acids by the addition of salts,” Z. Phys. Chem.

(Leipzig), 31 (1899) 197.

[2] J. N. Brönsted, “On the activity of electrolytes,” Trans. Faraday Soc., 23 (1927) 416

[3] I. M. Kolthoff, “Indicators with an alkaline character are given an acid tint by neutral salts ^

reverse for acidic indicators,” Chem. Weekblad, 13,(1916) 284

[4] H. S. Harned, “On the thermodynamic properties of a few concentrated salt solutions,” Trans.

Farady Soc., 23 (1927) 462.

[5] G. D. Christian, “The effects of salts on titrations,” CRC Critical Reviews in Analytical

Chemistry, July 1975, 119-163.

[6] W. L. Schertz and G. D. Christian, “Effects of neutral inorganic salts on potentiometric titration

curves of weak bases in nonaqueous solvents,” Anal. Chem., 44 (1972) 755

[7] C. E. Matkovich and G. D. Christian, “Salting-out of acetone from water – basis of a new

solvent extraction system,” Anal. Chem., 45 (1973) 1915

[8] C. E. Matkovich and G. D. Christian, “Solvent extraction of metal chelates into water-

immiscible acetone,” Anal. Chem., 46 (1974) 102

[9] G. B. Frankforter, “Equilibria in the systems, water, acetone and inorganic salts,” J. Am. Chem.

Soc., 36 (1914) 1103

[10] R. E. Majors, “Salting-out liquid-liquid extraction,” LCGC North America, 27 (2009) 526

[11] Y. Q. Tang, N. Weng, “Salting-out assisted liquid-liquid extraction for bioanalysis,”

Bioanalysis, 5 (2013) 1583

[12] I. M. Valente, J. A. Rodriques, “Recent advances in salt-assisted LLE for analyzying

biological samples,” Bioanalysis, 7 (2015) 2187

[13] D. C. Leggett, T. F. Jenkins, P. H. Mirares, “Salting-out solvent extraction for

preconcentration of neutral polar organic solutes for water,” Anal. Chem., 62 (1990) 1355

Keywords Proton activity, Levelling effect of salts, Salting-out effect, Extraction of polar solutes

PL-2 40


Sensitive Bioimaging of Cellular Functional Biomolecules

Huangxian Ju*

State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry,

Nanjing University, Nanjing 210023, P. R. China

*Email: [email protected]

Cellular functional biomolecules have been regarded as attractive targets for biomedical research,

molecular diagnostics and disease therapy. Our recent efforts have been devoted to in situ analysis

and highly selective detection of various cellular functional biomolecules and precise near-infrared

cancer therapy. This talk will introduce our research results in bioimaging of cellular functional

biomolecules, including electrochemical, chemiluminescent, scanometric, fluorescence, Raman and

mass spectroscopic imaging for detection and in situ analysis of these molecules, such as glycans

and protein-specific glycans on living cell surface [1], intracellular microRNA [2], sialyltransferase

[3], telomerase [4], ATP and caspases [5]. Some nanoprobes designed for for real-time targeted

imaging and precise near-infrared therapy against cancer are also discussed [6]. The MALDI-MS

patterning of caspase activities and its potential for drug resistance evaluation will be reported [7].

A recent work designs a structure switchable “lock-smart key” for cell–subtype specific siRNA

delivery [8]. Lastly, this talk will introduce a highly catalytic network by target-triggered cascade

assemblyfor selective analysis and sensitive bioimaging.

References

[1] H. X. Ju, et al. J. Am. Chem. Soc. 2008, 130, 7224; Angew. Chem. Int. Ed. 2009, 48, 6465;

Anal. Chem. 2010, 82, 5804; Chem. Commun. 2011, 47, 3742; Anal. Chem. 2012, 84, 1452; Anal.

Chem. 2013, 85, 11153; Chem. Sci. 2015, 6, 3769; Chem. Sci. 2016, 7, 569; Anal. Chem. 2016, 88,

2923; Angew. Chem. Int. Ed. 2016, 55, 5220.

[2] H. X. Ju, et al. Biomaterials 2011, 32, 387; Angew. Chem. Int. Ed. 2012, 51, 4607; Chem. Rev.

2013, 113, 6207; Chem. Commun. 2014, 50, 13604; Chem. Commun. 2015, 51, 2141.

[3] H. X. Ju, et al. Sci. Rep. 2015, 5, 10947.

[4] H. X. Ju, et al. J. Am. Chem. Soc. 2013, 135, 13282; Anal. Chem. 2014, 86, 8642; J. Am. Chem.

Soc. 2014, 136, 8205; Chem. Commun. 2016, 52, 1226.

[5] H. X. Ju, et al. Nanoscale 2015, 7, 15953; Chem. Sci. 2015, 6, 3365.

[6] H. X. Ju, et al. J. Am. Chem. Soc. 2013, 135, 18850; Angew. Chem. Int. Ed. 2014, 53, 9544;

Chem. Sci. 2015, 6, 5969; Anal. Chem. 2015, 87, 3841; Chem. Commun. 2015, 51, 10831;

Biomaterials 2015, 67, 323; ACS Applied Mater. Interf. 2015, 7, 19016.

[7] H. X. Ju, et al. Angew. Chem. Int. Ed. 2016, 55, 6667; Anal. Chem. 2014; 86, 8275; Anal.

Chem. 2015, 87, 4409.

[8] H. X. Ju, et al. Nat. Commun. 2016, 7, accepted on Oct 17.

PL-3 41


Flow-based immunoassay using sequential injection and centrifugal pumping

techniques

Toshihiko Imato

Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, Motooka, Nishi-ku,

Fukuoka 819-0395 Japan

*E-mail: [email protected]

Immunoassay is recognized as one of the selective analytical methods due to the fact that a

specific reaction of an antibody with an analyte (antigen) is utilized. The sensitivity of

immunoassay can be enhaced by combining with an enzyme-linked simmunosorbent assay

(ELISA), where the enzyme produces a large amount of product recyclingly for detecting with

highly sensive techniques such as fluorescence or chemiluminescence spectrometory or an

electrochemical method. The ELISA method has been used in many analtycal fields such as

diagonosis of health, safty of foods and enviromental monitoring. However, one of the

disadvanges of the ELISA method in general involves many labrious and time-consuming

procedures such as the washing, separation of bound and free antigens, addition of sample and

reagents etc. In order to overcome this disadvantage, we have developed a sequential injection

analysis (SIA) combined with a magnetic microbeads injection technique. In this method, an

immunoreaction was carried out on the surface of the magnetic microbeads immobilized with an

antibody for a target molecule (antigen). We have demonstrated the usefulness of our method by

application to the determination of anionic and nonioinc surfacants based on chemiluminescence

detection [1,2]. An electrochemical immunoassay was performed by replacing the

chemikuminescence detector with an electrochemical one, where an enzyme produing an

electroactive product was used as a labeling enzyme for a substrate [3,4].

A flow analysis on a compact disk (CD)-type microchip has been reacently paid great attention

with respect to centrifugal pumping because flow can be driven by rotation of the microchip

without any pumping system and sequence injection procedures can be performed by controlling a

rotation speed of the microchip. We have developed the sequential injection immunoassay [5,6] or

bioassay [7] on the CD-type microchip as an alternative flow analysis based on the SIA developed

by us. Chemiluminescence, fluorescence and electrochemical detections have been applied to the

immunoassay and bioassay on the CD-type microchip. In the present paper, flow-immunoassay

based on SIA using magnetic microbeads and based on centrifugal pumping on the CD-type

microchip developed by us will be presented including a new detection system with

electrogenerated chemiluminescence using carbon quantum dots.

References: [1] R. Q. Zhang, K. Hirakawa, D. Seto, N. Soh, K. Nakano, T. Masadome, K. Nagata, K. Sakamoto, T. Imato,

Talanta, 68, 231-238 (2005). [2] R. Q. Zhang, H. Nakajima, N. Soh, K. Nakano, T. Masadome, K. Nagata, K. Sakamoto, T. Imato, Anal.

Chim. Acta, 600, 105-113 (2007). [3] K. Hirakawa, M. Katayama, N. Soh, K. Nakano, T. Imato, Anal. Sci., 22, 81-86 (2006)

[4] K. Hirakawa, M. Katayama, N. Soh, K. Nakano, H. Ohura, S. Yamasaki, T. Imato, Electroanal., 18, 1297-

1305 (2006). [5] S. Guo, K. Nakano, H. Nakajima, K. Uchiyama, A Hemmi, Y. Yamasaki, S. Morooka, R. Ishimatsu, T.

Imato, Pure Appl. Chem. 84, 2027-2043 (2012). [6] S. Guo, R. Ishimatsu, K. Nakano, T. Imato, Talanta, 133, 100-106 (2015), [7] P. Rattanarat, P. Teengam, W. Siangproh, R. Ishimatsu, K. Nakano, O. Chailapakul, T. Imato, Electroanal.

27, 703 – 712 (2015).

Acknowledgments: This work was partly supported by JSPS KAKENHI Grant Number 16H04166.

Keywords: sequential injection analysis; compact disk-type microchip; immunoassay

PL-4 42


Immersive analytical science: From the lab, to on site, to in situ

Eric Bakker1*

1Department of Inorganic and Analytical Chemistry, University of Geneva, 1211 Geneva, Switzerland


Analytical chemistry strives to continuously move from traditional bench top instrumentation to the

site of interest. Many, if not most analytical questions must be asked with a view of a much larger

system that changes continuously, and where chemical speciation cannot be adequately maintained

with sampling techniques.

This talk will site recent exciting examples of how analytical science can move away from the

traditional laboratory and closer to the system of interest. The discussion will be mainly focused on

techniques to detect ionic and other small molecular/inorganic species, using electrochemistry as

readout. The applications area that will be touched on will include biomedicine and environmental

monitoring.

Unfortunately, one must admit that despite enormous chemical advances made, electrochemical

protocols have often ignored the needs of the environmental analytical scientist. Potentiometry, for

example, is a ubiquitous technique but still relies on the same liquid junction reference electrodes as

their laboratory counterparts a century ago. Also, while direct potentiometry is conceptually very

elegant, as it affords a direct translation of chemical information into an electrical signal, the

smallest potential drifts can result in unacceptable error. As a consequence, recalibration-free

measurements are largely still not possible today, which limits their usefulness away from the

controlled laboratory.

This talk will introduce the topic of potentiometric sensors and show how its methodology can be

adapted to robust in situ monitoring applications. The main line of thought will focus on exhaustive

methodologies performed on thin sample layers. One example is the direct monitoring of total

alkalinity without the need for sampling or pumping, volumetric titrations, or the preparation of

standards. It is accomplished with two membrane electrodes placed opposite each other across a

thin layer gap that is contact with the sample solution. One electrode serves as an electrochemically

controlled proton pump while the other detects the resulting change in pH. The talk will include

concepts to detect a variety of other species in solution in a robust manner.

PL-5 43


Protein-based luminescent sensors for single cell analysis

Takeaki Ozawa

Department of Chemistry, School of Science, University of Tokyo, Japan

Engineered fluorescent and bioluminescent proteins are now widely used for analysis of small

molecules and various intracellular events in live cells. The luminescent proteins are entirely

genetically encoded and can be engineered to generate functional probes. I herein describe a novel

design of engineered fluorescent proteins and luciferases for the analysis of intracellular signaling;

the principle is based on complementation and reconstitution of the split-reporter fragments when

they are brought sufficiently close together. To demonstrate the usefulness of the split reporters, I

will focus on imaging technologies of RNAs, apoptosis, protease activities, and GPCR-arrestin

interactions in live cells. These less-invasive techniques are widely applicable for understanding

complex biological systems with high spatiotemporal resolution.

References:

1. Confocal bioluminescence imaging for living tissues with a caged substrate of luciferin. M.

Hattori, et al., Anal. Chem., 88, 838-844 (2016).

2. In Situ Characterization of Bak Clusters Responsible for Cell Death Using Single Molecule

Localization Microscopy. Y. Nasu, et al., Sci. Rep., 6, 27505 (2016).

3. Optogenetic activation of axon guidance receptors controls direction of neurite outgrowth. M.

Endo, et al., Sci. Rep., 6, 23976 (2016).

4. Genetically Encoded Fluorescent Probe for Imaging Apoptosis in Vivo with Spontaneous GFP

Complementation. Y. Nasu, et al., Anal. Chem., 88, 838-844 (2016).

5. An optogenetic system for interrogating the temporal dynamics of Akt. Y. Katsura, et al., Sci.

Rep., 5, 14589 (2015).

6. Simultaneous time-lamination imaging of protein association using a split fluorescent timer

protein. A. Takamura, et al., Anal. Chem., 87, 3366-3372 (2015).

PL-6 44


Selective recognition of chemical species at surface modified electrodes

Jeong-Wook Oh1, Yang-Rae Kim2 and Hasuck Kim1,3*

1Department of Chemistry, Seoul National University, Seoul 08826, Korea

2Department of Chemistry, Kwangwoon University, Seoul 01897, Korea 3Department of Energy Systems, DGIST, Daegu 49288, Korea


Detecting trace amount of ions or molecules is important in many areas such as medicine,

chemistry, biology, and environmental applications for life and environment. Various

electrochemical methods for selectively sensing of chemical species are demonstrated, that are

based on selective interactions between target species and surface treated electrode. Interactions

employed are coulombic interaction, complexation, specific bond formation and antibody-antigen

interactions.

First example is based on electrostatic interaction; negatively charged multi-walled carbon

nanotubes (MWCNTs) were prepared using simple sonication technique with citric acid (CA) for

the electrochemical detection of dopamine (DA). For comparison, positively charged

polyethyleneimine (PEI)/MWCNT/GC electrode and pristine MWCNT/GC electrode were also

prepared. The negatively charged CA/MWCNT/GC electrode remarkably enhance the

electrochemical sensitivity and selectivity towards DA, showing the linear relationship in the range

of 10–1000 nM even in the presence of 105 times concentrated AA, which is attributed to

electrostatic interaction addition to catalytic behavior of MWCNT. The limit of detection (LOD)

value of 4.2 nM for DA at CA/MWCNT/GC electrode is one of the lowest values and is low

enough for the early diagnosis of neurological disorder in the presence of physiological AA

concentration (~0.5 mM).1

Second example is based on the complex formation. A multisignaling assay for the selective

detection of Fe3+ ions with a cruciform-shaped alkynyl pyrene bearing four peripheral N, N-

dimethyl ethynyl aniline units. Upon exposure to various metal ions, only Fe3+ showed significant

changes in the optical, electrochemical and electrochemiluminescent behavior of the ligand.2

Complexation is due to the coordination of Fe3+ ions to the N-atoms of the peripheral N, N-dimethyl

aniline DMA moieties in a 1:2 complex mode. The compatibility of the ligands with multiple tools

gives a clear analytical advantage, facilitating consistently accurate results.

Details and other interaction based methods3,4 will be discussed.

1) Jeong-Wook Oh, Yeo Woon Yoon, Jihye Heo, Joonhee Yu, Hasuck Kim, Tae Hyun Kim,

Talanta, 147 (2016) 453-459.

2) Jeong-Wook Oh, Tae Hyun Kim, Sang Wook Yoo, Yeon Ok Lee, Yujin Lee, Hasuck Kim,

Joohoon Kim, Jong Seung Kim, Sensors and Actuators B: Chemical 177 (2013) 813-817.

3) Jeong‐Wook Oh, Yeon Ok Lee, Tae Hyun Kim, Kyoung Chul Ko, Jin Yong Lee, Hasuck Kim,

Jong Seung Kim. Angew. Chem. Int. Ed., 48 (2009) 2522-2524.

4) Yang-Rae Kim, Hyo-Ju Seo, Jeong-Wook Oh, Hyunchang Lim, Tae Hyun Kim, and Hasuck

Kim, Electroanalysis, 25 ( 2013) 1056-1063.

Keywords Electrostatic interaction; Dopamine detection; MWCNT; Fe3+ detection; Multisignaling

assay

PL-7 45


Approaches to automated miniaturized sample preparation

Hian Kee Lee1,2

1Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543

2National University of Singapore Environmental Research Institute, T-Lab Building #02-01,

5A Engineering Drive 1, Singapore 117411

Email: [email protected]

Modern autosamplers are now virtually purchased by default integrated with chromatography-mass

spectrometric systems. They are powerful, high-performing systems. However, normally, standard

applications are applied when using these integrated platforms with methods provided by the

respective vendors. Thus, the full capabilities of the autosampler is not taken advantage of. Indeed,

such autosamplers can be reprogrammed to undertake more sophisticated operations that those in

the vendor-supplied methods. For the past several years, we have been enabling fully automated

sample preparation procedures by exploiting the full capabilities of commercial autosamplers, such

as those from CTC Analytics and Gerstel. We have written macros to control more precisely and in

a more complex way their operations so as to be able to conduct fully automated membrane-assisted

liquid-phase microextraction (LPME), plunger-in-needle LPME (which is very similar to solid-

phase microextraction except that the extractant phase is liquid rather than solid), dispersive liquid-

liquid microextraction, dissolvable sorbent solid-phase extraction, bubble-in-drop microextraction,

etc. In this talk, we describe these studies by way of encouraging fuller use of these highly-

programmable autosampler systems.

PL-8 46


Femtosecond ionization mass spectrometry: an advanced tool for the analysis of

pollutants, explosives, and nerve agents

Akifumi Hamachi1, Tomoko Imasaka2, Totaro Imasaka3*

1Deparatment of Applied Chemistry, Graduate School of Engineering, Kyushu University, Motooka 744,

Nishi-ku, Fukuoka 819-0395, Japan 2Laboratory of Chemistry, Graduate School of Design, Kyushu University, 4-9-1 Shiobaru, Minami-ku,

Fukuoka 815-8540, Japan 3Division of International Strategy, Center of Future Chemistry, Kyushu University, 744 Motooka, Nishi-ku,

Fukuoka 819–0395, Japan


During past decades, new analytical instruments are developed for the measurements of pollutants

such as polycyclic aromatic hydrocarbons, polychlorinated biphenyls, dioxins, and pesticides used

in agriculture. More recently, it is urgently required to develop an analytical instrument for

detection of explosives and nerve agents. Laser ionization mass spectrometry provides us a

molecular ion in most cases in mass spectrometry and is useful for identification of the analytes in

complex matrices. In addition, this technique provides us subfemtogram detection limits and then it

is useful for ultratrace analysis.

We developed a time-of-flight mass spectrometer with a mass resolution of 1000, which is based on

a linear-type configuration and allows the evaluation of the excess energy occurred in the process of

multiphoton ionization: this instrument is commercially available from Hikari-GK (Fukuoka,

Japan). The third harmonic emission (267 nm) of a femtosecond Ti:sapphire laser (800, 1-6 mJ, 1

kHz, 35 fs) was mainly used as an ionization source. The mass spectrometer was hyphenated with a

gas chromatograph for comprehensive analysis of the sample based on two-dimensional display

(GC/MS).

A variety of organic compounds were measured using the above instrument, e.g., nitro aromatic

hydrocarbons extracted from particulate matter 2.5 (PM2.5) collected in Fukuoka, Japan. More

recently, several types of explosives were measured based on ultraviolet femtosecond ionization.

For example, triacetone triperoxide (TATP), an explosive, is known as a compound that provides no

molecular ion in conventional mass spectrometry based on electron ionization. Thus, current

technology is somewhat unreliable, since the ions corresponding to the fragments originate from a

variety of sources such as cosmetics in the environment. However, a molecular ion can be clearly

observed in femtosecond ionization mass spectrometry [1]. It should be noted that this compound

has no absorption band at 267 nm and ionized through a process of non-resonant two-photon

ionization, as can be recognized by quantum chemical calculation. This favourable result is

attributed to the fact that non-resonant ionization becomes more efficient by reducing the laser pulse

width and then increasing the peak power of the laser. Since the wavelength of the laser can be

optimized, the excess energy can be minimal in non-resonant ionization, preventing the

fragmentation from the ionized state of the molecule. On the other hand, trinitrotoluene (TNT) can

be efficiently ionized through a process of resonant two-photon ionization at 219 nm, which was

generated by four-wave Raman mixing in a hydrogen gas [1]. We systematically studied the effect

of laser pulse width in the femtosecond ionization, suggesting non-resonant ionization can be an

advantageous tool for efficient ionization and for observing a molecular ion [2]. We recently

measured nerve-agent metabolites after labelling them using a few chemicals for vaporization,

which were separated by GC and identified by femtosecond laser ionization MS.

References

1. A. Hamachi, T. Okuno, T. Imasaka, Y. Kida, T. Imasaka, Anal. Chem., 87, 3027-3031 (2015).

2. H. Kouno and T. Imasaka, Analyst, 141, 5274-5280 (2016).

Keywords Mass spectrometry; Femtosecond laser ionization; Pollutants, Explosives, Nerve Agents

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