Preparation and evaluation of a new solid-phase microextraction fiber based on polythionine for analysis of phthalate esters in aqueous samples

Abstract

Polythionine was prepared by a simple electrochemical method and used as solid-phase microextraction coating for headspace extraction and analysis of four phthalate esters (dioctyl phthalate, benzyl butyl phthalate, di-n-butyl phthalate, and di-iso-butyl phthalate) by gas chromatographic-flame ionization detector. The thionine polymerization was performed at pH of 9 on a Pt wire. Made ready coating displayed a good thermal stability (up to 280 °C). The effects of three extraction parameters, containing salt effect, temperature and extraction time, on the extraction efficiencies of phthalate esters were evaluated. Under the optimized conditions, limits of detection were among 0.34–1.67 µg L−1. The inter-day and intra-day deviations of relative standard, attained at 50 µg L−1, were 7.64–10.62% and 10.14–12.84%, respectively. The method capability for analysis of the phthalates in real samples of cheese water and wastewater was evaluated and relative recoveries were between 82.63 and 119.50%.