Determination of aqueous chlorophenols by microwave-assisted headspace solid-phase microextraction and gas chromatography

A pretreatment technique denoted microwave-assisted headspace solid-phase microextraction (MAHS-SPME) has been designed and studied for one-step in-situ sample preparation before analysis of aqueous chlorophenols (CP). The aqueous CP are extracted on to a solid-phase microextraction fiber directly in the headspace with the aid of microwave irradiation. After collection on the SPME fiber the CP were desorbed in a GC injection port and analyzed by gas chromatography with electron-capture detection (GC-ECD). Experimental conditions (pH, addition of salt to the sample solution, microwave power and irradiation time, and temperature and time of desorption) were optimized to obtain the most efficient extraction. The results indicated that the highest extraction efficiency (recovery > 93%) and lowest RSD (< 8.0%) were obtained by irradiation of sample solution at pH 2 with medium-power microwaves for 5 min, and desorption at 300 degreesC for 3 min. Detection limits were approximately 0.1 to 2.0 mug L-1. The proposed method is a very simple, rapid, and solvent-free procedure for collection of CP from complicate sample matrixes. Its application was illustrated by the analysis of trace CP in landfill leachates.