equilibrium sampling of hydrophobic organic pollutantsdepartment of environmental science aarhus...

Department of Environmental ScienceAARHUS UNIVERSITY

Equilibrium Sampling of Hydrophobic Organic Pollutants

Philipp Mayer ([email protected])Aarhus University, Denmark

Contributors:

Annika

Jahnke

(ITM, Stockholm University, Sweden), Kimmo

Mäenpää

(University of Eastern Finland), Rik

Kraaij, Wouter

Vaes,

Fredrik Reichenberg

and more

Funding:

Danish Research Council, Swedish

MISTRA & FORMAS, EU- ALARM, EU-NOMIRACLE, EU-OSIRIS, EU-MODELPROBE, EU-Marie Curie, DK-REMTEC, CEFIC-LRI and Ph.D. programs RECETO & STAiR.


Outline-

Equilibrium sampling of hydrophobic organic chemicals in sediment and water

-

Validation and QA/QC considerations for equilibrium sampling with silicone

-

Relating equilibrium sampling to conventional monitoring


Why

passive sampling in sediment?

•

Csediment

often higher and more stable than Cwater

•

Benthic bioconcentration

is crucial for both benthic and pelagic bioaccumulation

•

Diffusive pollutant flux from historically polluted sediment? (from high to low Cfree

)

•

Sediment sample can be brought to the laboratory

•

Organic matter can enhance the sampling kinetics


Equilibrium sampling device

1.

Bring (passive) sampler into equilibrium (asampler

=amedium

)2.

Measure concentration in sampler

3.

Translate to chemical activity, fugacity or Cfree

Mayer et al., ES&T, 2003, V 37: 184A-191A


Equilibrium Sampling Device: a

Freely

dissolvedMatrix


Freely

dissolvedMatrix

Equilibrium

sampling device

(eg SPME)

Equilibrium Sampling Device


PDMS as a sampling materialPDMS is

versatile

and used in a large variety of matrices

•

Soil•

Sediment

•

Surface water•

Digestive fluids

•

Plasma•

...

L. van der Wal et al., Environ. Sci. Technol. 2004, 38, 4842.F. Reichenberg et al., Chem. Cent. J. 2008, 2, 8.

P. Mayer et al., Environ. Sci. Technol. 2000, 34, 5177.G. Cornelissen et al., Environ. Toxicol. Chem. 2008, 27, 499.

A.G. Oomen et al., Anal. Chem. 2000, 72, 2802.S. Ulrich et al., J. Chromatogr. B 1999, 731, 231.


1) Matrix-SPME with disposable fibers

1.

Equilibrate thin polymer with sample(aPDMS

=aSample

)

Mayer et al, ES&T, 2000, V 34: 5177-5183

Mayer et al., ES&T, 2003, V 37: 184A-191A

kCounts

2.0

1.5

1.0

0.5

kCounts

5

4

3

2

1

Hexa

chlo

robe

nzen

e

0

25

50

75

100

0.0

0.5

1.0

1.5

2.0

kCounts

kCounts

Flu

Flu

32.531.0minutes

0.0

2.5

5.0

7.5

10.0

12.5

15.0

PCB-

52

PCB-

65

PCB-

52

PCB-

65

kCounts0.00

0.25

0.50

0.75

1.00

1.25

1.50

kCounts

Hexa

chlo

roben

zene

28.0

2. Measure CPDMS

3. Apply conversion factor:

Cfree

=CPDMS

/KPDMS,water

a = CPDMS

* γPDMS

Department of Environmental ScienceAARHUS UNIVERSITY Philipp Mayer

ES&T, 2003


2) Automated headspace-SPME Legind

et al, Anal Chem

2007: 2869-2876; Mäenpää

et al, ES&T 2011: 1041-1047.

(Semi)volatile

Analytes:–

BTEX, alkanes

and NAPH

–

PCBs

Matrices:–

soil, sediment, wood, NAPL

–

no addition of water!!!

External Calibration:–

above methanol standards

–

above spiked lipids0 25 50 75 100

0

4000

8000

12000

16000

Nonane

Benzene

Decane

oXylene

Naphthalene

tSPME (min)

Peak

are

a

Equilibrate SPME fiber above the sample


3) Polymer coated vials

•

micrometer thin coating reduces equilibration times

•

multiple coating thickness to confirm valid sampling

•

yields an extract that can be measured with any instrument

http://www.journal.chemistrycentral.com/content/2/1/8


4) Passive equilibrium sampling in fish collaboration with Stockholm University

•

140-620 µm•

Different immersion times

•

Thorough surface cleaning

A. Jahnke et al., Chemosphere 2009, 77, 764-770.A. Jahnke

et al., ET&C 2011, 7, 1515-1521.

•

Solvent extraction, cleanup, GC/MS


Equilibrium

sampling in water

•

Equilibration

(HOC) slower

than

in sediment

•

Not strictly

time integrative

•

Short equilibration

times require

micrometer thin

polymers, which

are

best

coated

on

inert

support (glass

fiber fabric, glass

or

metal)

•

Multiple coating thicknesses

to cover wide range of analytes


Validation and QA/QC considerations for equilibrium sampling with PDMS


Assumptions

and validity

criteria

1.

equilibrium2.

negligible depletion

3.

absence of surface fouling artifacts4.

constant Kpolymer,water

(GC columns, SPME)•

linear isotherms

•

no competition5.

Kpolymer,water

not affected by matrix


Criteria 1-3: Sampling with multiple thicknesses

F. Reichenberg et al., Chem. Cent. J. 2008, 2, 8.

Benzo(a)pyrene

0

50

100

0 10 20 30 40VPDMS (L)

n (p

mol

e)

Reichenberg

et al., 2010,

Environ. Poll. 158: 1214 – 1220.

Confirms:

1.

equilibrium

2.

negligible depletion

3.

no surface artifacts

Do complex matrices modify the sorptive

properties of

polydimethylsiloxane

(PDMS) for non-polar organic chemicals?

Annika Jahnke* and Philipp Mayer‡

* Department of Applied Environmental Science (ITM), Stockholm University, Sweden

‡

National Environmental Research Institute (NERI), Aarhus University, Denmark

26 May 2010

A. Jahnke & P. Mayer, J. Chromatogr. A 2010, 1217, 4765-4770.

•

Humic substances: humic and fulvic acid solution, sediment suspension, soil slurry

•

Proteins: biotest

medium, milk, mayonnaise, body lotion•

Complex heterogeneous tissues:

ground meat, fish fillet, mussels, calf liver•

Pure lipids: olive oil, fish oil, seal oil

15 investigated matrices

A. Jahnke & P. Mayer, J. Chromatogr. A 2010, 1217, 4765-4770.

Annika Jahnke

7 model compoundsNon-polar hydrophobic halogenated organic chemicals:•Polychlorinated biphenyls

PCB 3, PCB 28, PCB 52, PCB 101, PCB 105•Bromodiphenyl ether

BDE 3

•γ-Hexachlorocyclohexane

γ-HCH

Experimental design

Experimental step (1) Experimental step (2)Exposure to the model compounds via headspace of spiked olive oil: 28 d at 30 °C

n = 2

n = 17

•

Matrix- immersion

of PDMS- coated

SPME fibres

•

1 h

> 34 d

•

Thorough surface

cleaning

Matrix influence regarding PCB 52

Group 1:98%

Humic acid 1 d

111%Fish

Slightly elevated in lipid-rich matrices.

Slightly elevated in lipid-rich matrices.


Relating equilibrium sampling to conventional monitoring

1) Relating CPDMS

to Clipid

2)

Relating Cfree

to Ctotal

in aqueous solutions


1) Relating CPDMS

to Clipid

1.

Clipid

= CPDMS * Klipid,PDMS

2.

CPDMS = a / γlipid

3.

Direct calibration using partitioning standards in lipids

Klipid,silicone

: Jahnke

et al. 2008. Chemosphere, 73, 1575-1581γlipid

: Mayer et al, 2009. Analytical Chemistry, 81, 1536-1542

HS-SPME and coated vials applied to soil and sediment. New calibration towards

concentrations in lipids of biota


Headspace-SPME

versus coated

glass

5 50 5005

50

500

31

28

52

101

153

105

138

slope = 0.854r2 = 0.81

Clipid,partitioning coated glass(µg g-1)

Clip

id,p

artit

ioni

ng H

S-S

PM

E(µ

g g-1

)

Mäenpää

et al. 2011. ES&T, 45, 1041–1047


Clipid,normalized

in larvae

versus Clipid,partitioning

Mäenpää

et al. 2011. ES&T, 45, 1041–1047

0 5 10 15 200

5

10

15

20

31

28

52

4944

101 110

151

149

118

153

105

138

156

180

A

y = 0.416xR2 = 0.89

Clipid,partitioning

(µg g-1)

Clip

id,n

orm

aliz

ed

(µg

g-1)


In tissue sampling of PCBs

Jahnke

et al. 2009. Chemosphere, 77, 764-770.Jahnke

et al. 2011. ET&C, 30, 1515-1521.


In tissue sampling of PCBsFarmed Atlantic salmon (19.1% lipid)

Jahnke

et al. 2009. Chemosphere, 77, 764-770.Jahnke

et al. 2011. ET&C, 30, 1515-1521.


2) Relating Cfree

to Ctotal

1.

Cfree

= ff

×

Ctotal

(ff= free

fraction)

2.

Ctotal

=Cfree

×

E (E= enhanced

capacity)


1.

Cfree

controlled

2.

Ctotal

measured


Fluoranthene in surface

waters Birch et al, 2010, Analytical

Chemistry, 82, 1142-1146.

CsolutionSpeciation Free

fraction


Concluding remarks›

Equilibrium sampling feasible even for highly hydrophobic organic chemicals

›

Measurement endpoints: ›

Cfree

›

chemical activity›

fugacity

›

Equilibrium sampling measurements can be related to lipid normalized concentrations in biota (Klipid,PDMS

) and total aqueous concentrations (ff and E)

›

Validation and QA/QC should focus more at the sampling than at the eventual instrumental analysis

equilibrium sampling of hydrophobic organic pollutantsdepartment of environmental science aarhus...

Documents