An Accelerated Solvent Extraction (ASE) Method For Passive (Air) Sampler PUF Disks Thomas Schiedek1, Michaela Laxander1, Sybille Ambs1,2, Christoph Schüth1 1Technische Universität Darmstadt, Institute for Applied Geosciences, Germany 2Hessisches Landesamt für Umwelt und Geologie, Department W4, Germany
[email protected],
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Introduction Poly-urethane foam (PUF) disks are widely used as a sorbent for e.g. passive air samplers (see Fig. 1 and related posters) to evaluate the air pollution with organic pollutants (see e.g. Jaward et al. 2004, Chaemfa et al. 2008), such as polyaromatic hydrocarbons (PAH) or polychlorinated biphenyls (PCB). A C
The cleaning before deployment and the extraction after the field application are usually done by standard soxhlet techniques, which last several hours or even days for each sample (Jaward et al. 2004, Chaemfa et al. 2008, Chaemfa et al. 2008). Automated extraction methods for organic compounds such as Accelerated Solvent Extraction (ASE) need usually less time for a comparable extraction efficiency and allows the repeated sequential extraction of a single sample. The aim of this study was to develop a rapid ASE method for PUF disks. PAH and PCB standards were used as model compounds to proof the extraction efficiency.
Materials, Methods and Tests
B
D
Fig. 1: A typical test site with air sampler (A), deposition sampler (B), soil samples (C) and chemical probes (D).
PUF disks (14 cm diameter and 1.35 cm thickness, density 0.03 g/cm3, destruction temperature 180°C) were purchased as non-cleaned from Klaus Ziemer GmbH, Germany and a Dionex ASE 300 model (Fig. 3) was used to develop a method. 6 PUF disks wrapped in kimtech wipes (Roth Chemie, Germany, Fig. 3) were pre-cleaned with dichloro-methane in 100 ml extraction cells with the ASE 300 and the method parameters described below. 5 of the disks were spiked with a PAH standard (16 EPA PAH +4 add. PAH) and a PCB standard (6 Ballschmiter PCB) with an absolute mass of 500 ng for each compound.
Fig. 3: PUF disks wrapped in kimtech wipes
After evaporation of the solvent all disks were wetted with 20 ml natural water to simulate maximum field humidity conditions. One disk was used as a laboratory blank and treated like the spiked disks to evaluate background contamination.
Fig. 2: Dionex ASE 300 model
Each sample was extracted with acetone under the following conditions: The cell was heated to 100°C at 100 bar for 10 min (static extraction step). Subsequently the cell was flushed with acetone (60% of cell volume) and purged for 100 s into a sampling bottle. The extraction was repeated and both extracts were combined. A third extraction was performed to reveal the extraction efficiency of the first 2 cycles.
Results A
700
A
1000 900
600
800
500
700
300 200 100
600
Naphthalene
Nap
2-methyl-Naphthalene
2-M-Nap
1-methyl-Naphthalene
1-M-Nap
Acenaphthylene
Acy
Acenaphthene
Ace
300
Fluorene
Flu
200
Phenanthrene
Phe
Anthracene
Ant
Fluoranthene
Fla
Pyrene
Pyr
Benz(a)anthracene
BaA
Chrysene
Chr
Benzo(b)fluoranthene
BbF
Benzo(k)fluoranthene
BkF
Benzo(e)pyrene
BeP
Benzo(a)pyrene
BaP
Perylene
Per
Dibenz(a,h)anthracene
DbA
Indeno(1,2,3-cd)pyrene
Ind
Benzo(g,h,i)perylene
BghiP
ng
ng
400
500 400
100
Bg hi P
Db A
In d
Pe r
Ba P
Be P
Bk F
Bb F
Ch r
Ba A
r Py
F lA
t An
e Ph
160 140 120
120 PCB-28
100
PCB-52 PCB-101
80
PCB-138
100 80 60
PCB-153
60
40
PCB-180 40
20
20
PUF 2
PUF 3
PUF 4
PUF 5
PUF 6
Fig. 4: Results PCB extraction (A mass, B %)
P
Bg hi
Db A
In d
Pe r
Ba P
Be P
Bk F
Bb F
Ch r
Ba A
r Py
t
F lA
0
An
N 2- ap M -N 1- ap M -N ap
0
e
% recovery
Ph
140
B
F lu
160
0
F lu
PCB-180
Ac e
PCB-153
Ac y
PCB-138
Ac y Ac e
PCB-101
% recovery
B
PCB-52
2M -N ap 1M -N ap
PCB-28
Na p
0
Fig. 5: Results PAH extraction (A mass, B %)
- The results showed an extraction recovery of 86 - 139 % for PAHs and 85 - 105 % for PCBs (blank corrected values) with 2 cycles of the method described above (Fig. 4 & 5). The extreme recovery rates (contamination?) with more than 230% for BeP (Fig. 5B) cannot be explained, since background was low and extreme care was taken during operation (quartz sand recoveries ca. 90%). - The third extraction showed concentrations lower than 5% of the target compounds, the water phase contained no remarkable concentrations of PAH or PCB (beside Nap). - The blanks were usually lower than 1%. - The total extraction time is ca. 40 minutes for each sample. References
Acknowledgement
Jaward F.M., Farrar N.J., Harner T., Sweetman A.J., Jones K.C. (2004): Passive air sampling of PCBs, PBDEs, and organochlorine pesticides across Europe. Environmental Science & Technology 38, 34–41. Chaemfa, C., Barber J.L., Gocht T., Harner T., Holoubek I, Klanova J., Jones K.C. (2008): Field calibration of polyurethane foam (PUF) disk passive air samplers for PCBs and OC pesticides, Environmental Pollution, Volume 156, Issue 3, 1290-1297. Chaemfa C., Barber J.L., Kim K.S., Harner T., Jones K.C. (2009): Further studies on the uptake of persistent organic pollutants (POPs) by polyurethane foam disk passive air samplers, Atmospheric Environment, Volume 43, Issue 25, 3843-3849.
This work is supported by the German Research Foundation (DFG). Many thanks to the Hydrographisches Amt Bozen, the Forest Station Sarntal, the Administration of the National Park Stilfser Joch (South Tyrol, Italy), the Aerial Passenger Tramway Sulden, the local communes, the German Federal Environmental Agency Schauinsland (UBA), the Administration of the Black Forest (Germany) and all the local inhabitants and farmers for their great support in realization this project.
