Analysis of chloro- and nitrobenzenes in water by a simple polyaniline-based solid-phase microextraction coupled with gas chromatography.

A simple solid-phase microextraction (SPME) device, coupled with gas chromatography-electron capture detection (GC-ECD) was developed to detect trace levels of chloro- and nitrobenzene compounds in environmental water samples. Polyaniline (PANI) was chosen as the extraction material for the SPME device, and was electrochemically deposited on a stainless steel wire to achieve high mechanical stability. Due to the peculiar pi-pi conjugated structure, PANI coating shows a stable performance in high temperature (to 350 degrees C) and solvents (organic and inorganic). The porous structure of PANI film characterized by scanning electron microscopy (SEM) revealed high extraction efficiency. The possible extraction mechanism was explained by the study carried out using electrochemical impedance spectroscopy (EIS). Eight chloro- and nitrobenzene compounds were selected to evaluate the SPME-GC procedures. The key parameters such as extraction and desorption temperature and time, and the ionic strength were investigated and optimized. The method was applied to the detection of environmental water samples collected from Taihu Lake, representing nowadays contamination level under industrial impact. The whole PANI-SPME-GC method offers high accuracy and precision, high sensitivity and low detection limits. Thus, the method developed could be used as a new way to monitor the trace levels of chloro- and nitrobenzene compounds in real water bodies.