Development of a polymer inclusion membrane-based passive sampler for monitoring of sulfamethoxazole in natural waters. Minimizing the effect of the flow pattern of the aquatic system

Antibiotics are commonly used pharmaceuticals for both human and veterinary purposes. Wastewater treatment plants (WWTPs) are not designed to completely remove these compounds from their influents. Thus, some antibiotics are being continuously discharged in the environment and subsequently found in diverse natural waters. Sulfamethoxazole (SMX) is one of the most frequently detected antibiotics in WWTP effluents and environmental waters. It exerts harmful effects on living organisms and therefore, there is a need to monitor its presence in aquatic systems. This study focused on the development of a passive sampler incorporating a polymer inclusion membrane (PIM) with Aliquat 336 as the extracting agent/membrane carrier for the monitoring of SMX in aquatic systems. Different PIM compositions were tested and the PIM, composed of 30-wt.% cellulose triacetate (CTA), 26 wt.% Aliquat 336 and 44 wt.% of the plasticizer 2-nitrophenyl octyl ether (NPOE) provided the best SMX permeation from natural waters to a 2 mol L-1 NaCl receiving solution. It was demonstrated that the flow pattern of the source solution influenced significantly the performance of a sampler with traditional design. The flow pattern of aquatic systems cannot be controlled and this potentially endangers the reliability of passive sampling data collected in these systems. A passive sampler with a new design is proposed which has been found to minimize the influence of the flow pattern of the aquatic medium being monitored. (C) 2015 Elsevier B.V. All rights reserved.