Automated sorptive extraction-thermal desorption-gas chromatography-mass spectrometry analysis : determination of phenols in water samples

A recently developed method for the automated analysis of organic micropollutants in water samples was evaluated for the determination of phenols. Several phenols were selected from the priority pollutant lists to represent the entire range of these pollutants. The phenols are derivatized off-line with acetic anhydride, which is added directly to the water sample. After derivatization is complete, the sample is transferred to the analytical system where automated sample processing takes place. The sample (10 mL) is loaded onto a cartridge packed with polydimethylsiloxane particles, which extract the analytes from the water. After sample loading, the cartridge is dried with nitrogen to eliminate water and derivatization agent. The cartridge is then transferred to the analytical system in which thermal desorption and chromatographic analysis take place. Using mass spectrometric detection in the selected ion monitoring mode, detection limits are on the order of 1-5 ng/L.