Passive sampling for target and nontarget analyses of moderately polar and nonpolar substances in water

Abstract

The applicability of silicone rubber and low-density polyethylene (LDPE) as passive sampling materials for target and nontarget analyses of moderately polar and nonpolar substances was assessed through a field deployment of samplers along a small, polluted stream in Oslo, Norway. Silicone and LDPE samplers of identical surface area (but different volumes) were deployed at 6 sites in the River Alna for 49 d. Quantitative target analysis by gas chromatography-mass spectrometry (quadrupole, single-ion monitoring mode) demonstrated that masses of polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organochlorine compounds absorbed in the 2 polymeric materials were consistent with the current understanding of the control and mode of accumulation in these sampler materials. Some deviation was observed for decabromodiphenyl ether (BDE-209) and may be linked to the large molecular size of this substance, resulting in lower diffusivity in the LDPE. Target and nontarget analyses with gas chromatography coupled to high resolution time-of-flight mass spectrometry allowed the identification of a wide range of chemicals, including organophosphate compounds (OPCs) and musk compounds (galaxolide and tonalid). Semiquantitative analysis revealed enhanced quantities of the OPCs in silicone material, indicating some limitation in the absorption and diffusion of these substances in LDPE. Overall, silicone allows nontarget screening analysis for compounds with a wider range of log octanol-water partition coefficient values than what can be achieved with LDPE.

Improvements in pollutant monitoring: Optimizing silicone for co-deployment with polyethylene passive sampling devices

“…However, LDPE does not sequester lower log K ow compounds (especially below 4) as well as another polymer, silicone (Rusina et al, 2007; Allan et al, 2013). Silicone has become an increasingly popular passive sampler in the past 10 years, and has been compared with LDPE to see differences in sequestration of target chemicals (Allan et al, 2010; Allan et al, 2013).…”

“…For example, at least 22 different types of materials, sorbents, or solvents are reported as receiving phases for passive sampling in a recent review (Vrana et al, 2005). Some PSDs specialize in targeting polar or non-polar compounds, and some materials can be used in tandem with others to broaden the total range of sequestered compounds (Petty et al, 2004; Harman et al, 2012; Allan et al, 2013). In addition to compound selectivity, considerations for using PSDs derive from previous development of uptake kinetics and published laboratory methods (Vrana et al, 2005; Rusina et al, 2007).…”

“…Silicone has become an increasingly popular passive sampler in the past 10 years, and has been compared with LDPE to see differences in sequestration of target chemicals (Allan et al, 2010; Allan et al, 2013). Although quantitative comparisons between aqueous concentrations were similar (< 2 to 3-fold among PAHs and PCBs), a dramatic increase of absorbed analytes was seen using silicone over LDPE for compounds with log K ow values lower than 6 (Allan et al, 2013).…”

“…Silicone has become an increasingly popular passive sampler in the past 10 years, and has been compared with LDPE to see differences in sequestration of target chemicals (Allan et al, 2010; Allan et al, 2013). Although quantitative comparisons between aqueous concentrations were similar (< 2 to 3-fold among PAHs and PCBs), a dramatic increase of absorbed analytes was seen using silicone over LDPE for compounds with log K ow values lower than 6 (Allan et al, 2013). More efficient absorption of analytes into the polymer can result in several advantages, including greater flexibility in deployment times, lower detection limits, and applications to bioassays due to greater concentrations in samples as long as extracts or silicone polymer background may be sufficiently reduced.…”

“…Ultimately, both polymers yield more accurate data than other passive sampling devices (Allan et al, 2010), so advantages of using one or the other depend on the choice of targeted compounds. Unlike previous comparisons of silicone and LDPE which focused on POPs (Allan et al, 2010; Allan et al, 2013), this research includes compounds that are transformation products of pollutants. One class of compounds that is well suited for a comparison between silicone and LDPE is oxygenated-PAHs (OPAHs).…”