Matrix solid-phase dispersion followed by gas chromatography-mass spectrometry for the determination of triclosan and methyl triclosan in sludge and sediments

Abstract

An expeditious method for the determination of triclosan (TCS) and methyl triclosan (MTCS) in sludge and sediment samples is presented. Extraction and cleanup steps were integrated in the same process using matrix solid-phase dispersion as sample preparation technique. Effects of different variables on the efficiency and the selectivity of the sample preparation process are discussed. Under final working conditions, samples (0.5 g) were dispersed with diatomaceous earth (1 g) and transferred to a polypropylene syringe containing 2 g of silica impregnated with sulphuric acid (15%, w:w). Analytes were recovered with 10 mL of dichloromethane. After solvent exchange to ethyl acetate, TCS was converted into the tert-butyldimethylsilyl derivative, and the extract was analysed by gas chromatography-mass spectrometry, without any additional cleanup. Obtained recoveries, for sludge and sediment samples spiked at different concentration levels, ranged from 86% to 113%, with associated standard deviations between 2 and 13%. Limits of quantification of the global method were 6 and 7 ng g(-1) for MTCS and TCS, respectively. Both compounds were detected in all the processed sludge samples with maximum concentrations of 191 ng g(-1) (MTCS) and 2,640 ng g(-1) (TCS). The parent bactericide was also found in some sediment samples at concentrations up to 200 ng g(-1).