Solid-phase microextraction using a diglycidyloxycalix[4]arene coated fiber combined with gas chromatography: very simple, rapid and sensitive method for the determination of chlorobenzenes in water

A fiber material for solid-phase microextraction (SPME) was obtained by blending 5,11,17,23-tetra-tert-butyl-25,27-dihydroxy-26,28-diglycidyloxycalix[4]arene with hydroxy-terminated silicone oil by sol-gel technology. It was used for headspace SPME combined with gas chromatography using electron capture detection to determine seven chlorobenzenes in water matrix. Optimum extraction conditions were 15 min at 20 A degrees C with a solution containing 300 g L(-1) sodium chloride. The fiber exhibits far higher extraction efficiency than the commercially available poly(dimethylsiloxane) (PDMS) and PDMS-divinylbenzene fibers. The detection limits range from 0.32 to 2.25 ng L(-1), and the relative standard deviations are < 5%. The calibration curves display a high level of linearity, with correlation coefficients ranging between 0.9996 and 1. The method was applied to analyze a lake water sample that was found to be polluted with 1,2,3,4-tetrachlorobenzene and hexachlorobenzene. It was compared to the United States Environmental Protection Agency method and other recently introduced methods. The results demonstrate that the technique is rapid, simple, and sensitive, and thus represents an attractive alternative for ultra-trace analysis of chlorobenzenes in water samples.