Measurement of benzophenones in human urine samples by stir bar sorptive extraction and thermal desorption-gas chromatography-mass spectrometry.

Determination of benzophenones (BPs) in human urine samples by stir bar sorptive extraction (SBSE) and thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS) is described. As analytes, BP, its metabolites benzhydrol (BP-OH) and 2-hydroxybenzophenone (2OH-BP), and its derivatives 2-hydroxy-4-methoxybenzophenone (BP-3) and 2-hydroxy-4-methoxy-4'-methylbenzophenone (BP-10) were selected. After enzymatic hydrolysis, a polydimethylsiloxane (PDMS) stir bar was placed in a urine sample diluted 1:1 with water and stirred for 60 min at room temperature. The limit of quantification (LOQ) of BPs is 0.2-0.5 ng ml(-1) (ppb). The method showed linearity over the calibration range (0.2-10 or 0.5-10 ng ml(-1)), and the correlation coefficients were equal to or higher than 0.993 for all of the analytes. The average recoveries of BPs were equal to or higher than 98.7% (RSD: 1.5-4.8%, n = 6).