Development of a polymer inclusion membrane (PIM) for the preconcentration of antibiotics in environmental water samples

Abstract

Antibiotics belong to the so called group of emerging organic contaminants (EOCs) and their presence in natural waters is of considerable environmental concern. Due to the need of their determination in natural waters at trace levels, we have developed a polymer inclusion membrane (PIM) capable of transporting six frequently used antibiotics (four sulfonamides, SAs, and two tetracyclines, TCs). Cellulose triacetate (CTA) and polyvinyl chloride (PVC) based membranes have been tested in transport experiments, with the former membranes exhibiting better permeability for the antibiotics studied. The addition of a plasticizer further improved the permeability of the CTA-based membranes. A PIM containing 30 wt% ETA, 26 wt% Aliquat 336, and 44 wt% 2-nitrophenyloctyl ether, provided the highest percentage of transport over a 24 h period, varying from 75% (sulfathiazole, STZ) to 100% (tetracycline, TC and oxytetracycline, OTC), except for sulfapyridine, (SPY) (55%). The feed solution in these transport experiments was at pH 9 while the stripping solution contained 1.0 M NaCl. A PIM-based device was constructed for the preconcentration of the antibiotics studied in its stripping solution and it was successfully applied to the preconcentration of these antibiotics in environmental water samples