Use of Mixed-Mode Ion Exchange Sorbent for the Passive Sampling of Organic Acids by Polar Organic Chemical Integrative Sampler (POCIS)

Abstract

Acidic herbicides are increasingly monitored in freshwater, since their high solubility favors their rapid transfer to the water phase. Therefore, contaminant levels in the water can vary rapidly and passive sampling would be preferred over spot sampling to integrate all pollution events over a given exposure time. In this work, we propose to compare the conventional pharmaceutical polar organic chemical integrative sampler (POCIS) with modified POCISs containing two different receiving phases: a standard polystyrene divinylbenzene polymer with a higher specific surface area (Chromabond HR-X) and a mixed-mode anion exchange sorbent providing additional strong anion exchange interaction sites (Oasis MAX). Due to its hydrophobic character, Chromabond HR-X had little interaction with water (no sampling of acidic herbicides); whereas Oasis MAX provided acceptable sampling parameters (longer kinetic regime together with higher sampling rates). Additional experiments with POCIS-MAX showed no influence of nitrates on analyte uptakes, and linear isotherms reaching 10 μg L⁻¹, supporting the applicability of this device for the sampling of organic acids in continental water. The performance and reference compound (PRC) approach would be then applicable for POCIS-MAX if no competition is observed with other anions, especially organic acids (e.g., humic acids).

Do Temporal and Spatial Parameters or Lifestyle of the Pacific Oyster Crasssostrea gigas Affect Pollutant Bioaccumulation, Offspring Development, and Tolerance to Pollutants?

“…Total average concentration of the 57 measured pesticides was 45 ± 31 ng L −1 in Arguin and 95 ± 7 8 ng L −1 in Grand Banc in 2010 (Budzinski et al, 2011). Antifouling biocides such as irgarol, diuron, and its metabolite DCPMU (1-(3,4-dichlorophenyl)-3-methylurea), as well as DMSA (Dimercaptosuccinic acid) and DMST (N,NDimethyl-N'-p-tolylsulphamide) were detected in the Arcachon Bay mostly at low concentrations <10 ng.L −1 (Budzinski et al, 2011;Fauvelle et al, 2012). The most abundant pesticides were metolachlor and alachlor with a dominance of their metabolites (Auby et al, 2007;Budzinski et al, 2011).…”

Development of a rapid and direct method for the determination of organic acids in peach fruit using LC–ESI-MS

“…Mixed-mode sorbents combine a polymeric poly (styrene-co-divinylbenzene) skeleton with ion-exchange groups, thus two types of interaction mechanisms are involved: reversed-phase and ion-exchange. This sorbent has been successfully employed to isolate organic compounds from complex matrices (Fauvelle et al, 2012;Fontanals, Cormack, & Sherrington, 2008;Liao, Zhu, Rubab, Feng, & Poon, 2010). However, to the best of our knowledge, this is the first time that a mixed-mode SPE has been employed for the isolation of organic acids.…”

The First Attempt at Non-Linear in Silico Prediction of Sampling Rates for Polar Organic Chemical Integrative Samplers (POCIS)

“…The largest variance in measured R s used corresponded to diclofop which had a 60% relative standard deviation (RSD), n = 15. 28 Many of the reported R s values vary by more than 2-fold depending on the methodology used for their estimation. 29 Although pH and temperature during collection of both sets of data used herein were similar, the type of calibration experiment applied was slightly different (flow-through and static renewal) therefore the resulting differences in the R s estimates from each investigation could have affected the performance of a model.…”

“…28 Briefly, 3 L of high-density polyethylene vessels were filled with ultrapure water, the pH adjusted to 7.6 with 20 mg L –1 NaHCO 3 and spiked with the mixture of respective compounds to expose the POCIS. Each vessel contained three POCIS devices for exposure to an aqueous-based standard mixture of 200 ng L –1 of each target compound (solvent <0.001%).…”