Traces determination of phenols in water by solid phase extraction followed by pentafluorobenzoylation

A simple and sensitive method for the trace determination of phenols in water is presented. Phenols were extracted from water samples with solid-phase extraction (SPE), and subsequently converted into pentafluorobenzoylates by reaction with pentafluorobenzoyl chloride in the presence of tetrabutylammonium bromide. The derivatives were determined by GC/ECD and GC/ITD-MS. Recoveries are better than those obtained with a conventional liquid-liquid extraction method for all phenols considered including phenol, alkyl-, chloro-, bromo- and mononitro-phenols with a commercial styrene-divinyl-benzene (SDB) SPE cartridge in a 500-ml water sample. The detection limits for phenols are 3 to 20 ng/l with GC/ECD and 10 to 60 ng/l with GC/ITD-MS.