Development and validation of an LC-APCI-MS/MS method for the determination of phenethyl isothiocyanate in human...

Phenethyl isothiocyanate (PEITC) is a promising chemopreventive agent present in cruciferous vegetables. This paper describes the development of a method for the determination of PEITC in human plasma by liquid chromatography/tandem mass spectrometry (LC-MS/MS). Atmospheric-pressure chemical ionization was found more suitable for ionization of PEITC than electrospray ionization. Because of the lability of PEITC, a combination of low temperature and acidification was applied to minimize the degradation during the sample collection and preparation procedure. A simple protein precipitation with acetonitrile was used for the preparation of plasma samples. The analyte and 1-phenylpropyl isothiocyanate as internal standard (IS) were subjected to chromatographic analysis on a C18 column (50 × 2.1 mm, 5 µm) using 85% methanol as mobile phase at a flow rate of 0.3 mL/min. The total analysis time for each chromatograph was 3 min and the results were linear over the studied range (5.00-250 ng/mL). The intra- and inter-day precision values were acceptable as per US Food and Drug Administration guidelines. This method was successfully applied in the determination of PEITC concentrations in plasma samples from healthy chinese Volunteers.