Convenient analytical method for quantitative determination of 23 pesticide residues in herbs by gas chromatography-mass spectrometry.

A convenient analytical method for quantitative characterization of 23 pesticides in three herbs has been developed. Pesticides tested included organochlorine, organophosphorus and pyrethroids. Primary secondary amine and graphitized carbon black as dispersive-SPE sorbent were applied to clean up the sample. Analytical method was established by using the technique of gas chromatography coupled with electron impact mass spectrometry in the selected ion monitoring mode (GC-MS-SIM). The recoveries of all pesticides were in the range of 78.4%-119.2% at three spiked levels of 5, 20 and 50 μg/kg, and the relative standard deviations were below 9.5%. The limits of detections of all pesticides were less than 3.0 μg/kg. This analytical method could be applied to the analysis of commonly used pesticides in commercial herbs.