19888 
Environ Sci Pollui Res (2015) 22:19887-19895 
Ö Springer 
However, a major problem of PDMS samplers is the co 
extraction of non-crosslinked silicone oligomers from the poly 
mer. Silicone oligomers can cause considerable analytical prob 
lems like blocking of high-performance liquid chromatographic 
(HPLC) columns or coating of gas chromatographic (GC) liner 
and columns (Smedes and Booij 2012). Therefore, exhaustive 
pre-cleaning prior to sampling and extract purification of 
PDMS sampler are necessary to minimize oligomer release 
and subsequent interference with chemical analysis (Smedes 
and Booij 2012; Shahpoury and Hageman 2013; O'Connell 
et al. 2014). Common pre-cleaning extraction techniques, e.g. 
Soxhlet extraction, are solvent- and time-intensive (Schafer 
et al. 2010; Smedes and Booij 2012; Shahpoury and Hageman 
2013). Despite of extensive pre-cleaning steps, PDMS sampler 
extracts often still contain traces of non-crosslinked silicone 
oligomers (Smedes and Booij 2012), and hence additional pu 
rification methods, such as C-18 column chromatography or 
HPLC-size exclusion chromatography (SEC) are needed 
(Smedes and Booij 2012; Shahpoury and Hageman 2013). 
Thus, a more rigorous, faster extraction technique with less 
solvent consumption as well as an efficient PDMS extract pu 
rification method would be favourable. 
In this study, accelerated solvent extraction (ASE) was used 
to facilitate the pre-cleaning and extraction process of silicone 
sheets with the aim to decrease time and solvent usage com 
pared to the commonly used methods. Additionally, extraction 
and purification of PDMS sampler were optimized in order to 
prevent silicone coating of analytical hardware such as GC-MS. 
Furthermore, total reflection X-ray fluorescence (TXRF) was 
applied as a new, very fast and easy methodology for the de 
tection and quantification of silicone oligomers in the final ex 
tract. The newly established methodology for passive sampler 
purification and extraction was applied on real marine samples. 
Materials and methods 
Experimental materials 
Materials 
Sampler strips of 55 x 90 x 0.5 mm (Altec, UK) were prepared 
from AlteSil silicone rubber sheets. All solvents used (ace 
tone, acetonitrile, dichloromethane, ethylacetate, «-hexane, 
methanol and «-pentane) were of HPLC gradient grade or 
better (J.T. Baker, USA). Nitrogen 5.0 (LINDE, Germany) 
was used for solvent evaporation. 
Table 1 Internal standards (IS) and performance reference compounds (PRC) used in this study 
Compound class Standard Compound Abbreviation Concentration IS (ng/mL) 
PRC (ng^sampler) 
PRC 
2,6-Dichlorobiphenyl 
CB10 
65.5 
Hexachlorobenzen-13C6 
HCB-13C6 
125.0 
2,4,6-Trichlorobiphenyl 
CB30 
100.0 
Lindane-13C6 
HCHG-13C6 
172.5 
2,2',4,6,6'-Pentacholorbiphenyl 
CB104 
100.0 
2,2',3,4,6,6'-Hexachlorbiphenyl 
CB145 
100.0 
1,1 -Dichloro-2,2-bis-(p-chlorphenyl)ethen-d8 
DDEPP-D8 
100.0 
2,2 ',3,4,5,5 '-Hexachlorobiphenyl 
CB141 
100.0 
2,2',3,4,4',5,6,6'-Octachlorobiphenyl 
CB204 
80.2 
IS 
£-hexachlorocyclohexane 
HCHE 
5.0 
1,2,3,4-Tetrachloronaphtaline 
TCN 
5.0 
2,2 ',3,4,5,5 ',6-Heptachlorobiphenyl 
CB185 
5.0 
PRC 
Fluorene-dl 0 
FL-D10 
500.0 
Pyrene-dlO 
PYR-D10 
500.0 
Benz[a]anthracene-dl2 
BAA-D12 
500.0 
1,2,3-Indenopyrene-dl2 
I123P-D12 
500. 
IS 
Naphthaline-d8 
NAPH-D8 
40.0 
Acenaphthene-d 10 
ACE-D10 
40.0. 
Anthracene-dlO 
ANT-D10 
40.0 
Fluoranthene-dl 0 
FLU-D10 
40.0 
Benz[e]pyrene-D 12 
BEP-D12 
40.0 
Benz[ghi]perylene-dl 2 
BGHIP-D12 
40.0 
One sampler consists of six PDMS strips