equilibrium sampling of hydrophobic organic pollutantsdepartment of environmental science aarhus...
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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.
Department of Environmental ScienceAARHUS UNIVERSITY
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
Department of Environmental ScienceAARHUS UNIVERSITY
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
Department of Environmental ScienceAARHUS UNIVERSITY
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
Department of Environmental ScienceAARHUS UNIVERSITY
Equilibrium Sampling Device: a
Freely
dissolvedMatrix
Department of Environmental ScienceAARHUS UNIVERSITY
Freely
dissolvedMatrix
Equilibrium
sampling device
(eg SPME)
Equilibrium Sampling Device
Department of Environmental ScienceAARHUS UNIVERSITY
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.
Department of Environmental ScienceAARHUS UNIVERSITY
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
Department of Environmental ScienceAARHUS UNIVERSITY
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
Department of Environmental ScienceAARHUS UNIVERSITY
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
Department of Environmental ScienceAARHUS UNIVERSITY
4) Passive equilibrium sampling in fish collaboration with Stockholm University
•
140-620 µm•
Different immersion times
•
Thorough sur- face 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
Department of Environmental ScienceAARHUS UNIVERSITY
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
Department of Environmental ScienceAARHUS UNIVERSITY
Validation and QA/QC considerations for equilibrium sampling with PDMS
Department of Environmental ScienceAARHUS UNIVERSITY
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
Department of Environmental ScienceAARHUS UNIVERSITY Philipp Mayer
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.
Department of Environmental ScienceAARHUS UNIVERSITY
Relating equilibrium sampling to conventional monitoring
1) Relating CPDMS
to Clipid
2)
Relating Cfree
to Ctotal
in aqueous solutions
Department of Environmental ScienceAARHUS UNIVERSITY Philipp Mayer
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
Department of Environmental ScienceAARHUS UNIVERSITY Philipp Mayer
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
Department of Environmental ScienceAARHUS UNIVERSITY Philipp Mayer
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)
Department of Environmental ScienceAARHUS UNIVERSITY Philipp Mayer
Department of Environmental ScienceAARHUS UNIVERSITY Philipp Mayer
In tissue sampling of PCBs
Jahnke
et al. 2009. Chemosphere, 77, 764-770.Jahnke
et al. 2011. ET&C, 30, 1515-1521.
Department of Environmental ScienceAARHUS UNIVERSITY Philipp Mayer
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.
Department of Environmental ScienceAARHUS UNIVERSITY Philipp Mayer
2) Relating Cfree
to Ctotal
1.
Cfree
= ff
×
Ctotal
(ff= free
fraction)
2.
Ctotal
=Cfree
×
E (E= enhanced
capacity)
Department of Environmental ScienceAARHUS UNIVERSITY Philipp Mayer
1.
Cfree
controlled
2.
Ctotal
measured
Department of Environmental ScienceAARHUS UNIVERSITY Philipp Mayer
Fluoranthene in surface
waters Birch et al, 2010, Analytical
Chemistry, 82, 1142-1146.
CsolutionSpeciation Free
fraction
Department of Environmental ScienceAARHUS UNIVERSITY Philipp Mayer
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