Direct acetylation followed by solid-phase disk extraction and GC-ITDMS for the determination of trace phenols in water

A rapid, accurate and sensitive method is described for the analysis of phenolic compounds, including phenol, alkylphenols, halogenated phenols and nitrophenols in tap, ground and river water samples. The method consists in direct acetylation of the aqueous phenols with acetic anhydride, extraction of the phenol acetates with a C-18 disk and analysis by gas chromatography with an ion-trap detector mass spectrometer. Using this method, the sample preparation time was approximately 1.5 h for six 1-L water samples, and recoveries for most of the phenolic compounds studied were more than 80% at concentration levels of 0.1 and 1.0 mu g L(-1). The detection limits were in the range 2 to 15 ng L(-1) for phenol, alkylphenols and halogenated phenols, and 25 to 50 ng L(-1) for nitrophenols.