Evaluation of polar organic chemical integrative and hollow fibre samplers for the determination of a wide variety of organic polar compounds in seawater

Abstract

The calibration of two passive samplers for the determination of 20 emerging organic compounds in seawater is described in this work: i) a new version of polar organic chemical integrative sampler (POCIS) containing 100 mg of mixed-mode anion exchanger (Strata X-AW) and 100 mg of polymeric HLB (Plexa) sorbent materials and using a highly porous Nylon membrane (30-μm pore size) and ii) polyethersulfone (PES) hollow fibre. Among the studied contaminants, herbicides, hormones, life style products (stimulants and artificial sweeteners), industrial chemicals (corrosion inhibitor and fluorinated compounds), personal care products and several pharmaceuticals were included. In the case of POCIS, both the sorbents and the Nylon membranes were extracted and analysed independently. The calibration set up consisted on a continuous-flow tank that was fed with a continuous flow of seawater (2 L/h) and a stock mixture of contaminants (20 mL/h), assuring a nominal concentration of ~ 600 ng/L (each analyte) in the tank. The uptake was linear in POCIS sorbent and Nylon membranes but exponential for PES hollow fibres. Furthermore, the highest sampling rates (Rs) values were obtained in POCIS sorbent (between 2.7 for acetaminophen and 491 mL/day for perfluoro-n-octanoic acid, PFOA) followed by Nylon membranes (between 3.6 for OBT and 50 mL/day for telmisartan) and the lowest were those from PES fibres (between 1.7 for bezafibrate and 157 mL/day for butylparaben). Additionally, five deuterated compounds ([2H5]-atrazine, [2H3]-amitriptyline, [2H7]-irbesartan, [2H3]-ketoprofen and [2H9]-progesterone) were studied as candidates for performance reference compounds (PRCs) in both POCIS and PES, and though [2H5]-atrazine, [2H9]-progesterone and [2H3]-amitriptyline showed acceptable results in the case of POCIS, only [2H5]-atrazine provided a good validation. In the case of PES fibres, the PRC corrections did not provide acceptable results due to a low dissipation of the PRCs. Finally, POCIS were deployed in two sites of the low part of the estuary of Bilbao (northern Spain) from where water samples were also taken and analysed. As a result, in addition to the overall good agreement between the passive and active samplings, passive samplers allowed the determination of several compounds that were below the detection limits in the active sampling.