Stir bar sorptive extraction and thermal desorption-gas chromatography-mass spectrometry for trace analysis of benzophenone and its derivatives in water sample

A simple and highly sensitive method called stir bar sorptive extraction (SBSE) and thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS), which is used for the determination of trace amounts of benzophenone (BP) and its derivatives, 2-hydroxy-4-methoxybenzophenone (BP-3) and 2-hydroxy-4-methoxy-4′-methylbenzophenone (BP-10), in river water samples, is described. A stir bar coated with polydimethylsiloxane (PDMS) is added to a 10 ml water sample and stirring is carried out for 120 min at room temperature (25 °C) in a vial. Then, the PDMS stir bar is subjected to TD-GC-MS. The detection limit is 0.5–1 pg ml−1 for BPs. The method shows good linearity and the correlation coefficients are higher than 0.997 for all the analytes. The average recoveries of the BPs are equal to or higher than 98.5% (R.S.D.: 1.5–5.1%). This simple, accurate, sensitive and selective analytical method may be used in the determination of trace amounts of BPs in river water samples.