Polyaniline-based fiber for headspace solid-phase microextraction of substituted benzenes determination in aqueous samples

A headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography and flame ionization detector (GC-FID) was applied to determine seven benzene derivatives in water samples. A polyaniline (PANI) fiber which was electrochemically coated on a stainless steel wire was employed to extract the target analytes from aqueous system. Five experimental parameters consisting of adsorption temperature, adsorption time, stirring rate, salt concentration and headspace volume were evaluated and optimized by means of a Taguchi's L-16 (4(5)) orthogonal array experimental design. The experimental results indicated that adsorption temperature and salt concentration were the most significant factors in the analysis procedure. The optimized conditions were as follows: 20 degrees C of adsorption temperature, a constant stirring speed of 600 rpm and 20 min of extraction carried out in 10 mL of water samples saturated with NaCl. The proposed method was linear approximately three orders (0.1-100 mu g L-1) of magnitude for the tested compounds, with linear correlation coefficients (r(2)) greater than 0.98. Relative standard deviation ranged from 5.3 to 8.4% and limit of detection was relatively low (0.01-0.06 mu g L-1). The proposed method was applied to determine the trace level compounds in natural water samples. (C) 2008 Elsevier B.V. All rights reserved.