Feng Qin

This method greatly facilitates the analysis of a large number of pesticides.

A novel liquid chromatography–tandem mass spectrometry (LC–MS/MS) method with a dual electrospray ionization (ESI) and atmospheric-pressure chemical ionization (APCI) source was developed for analysis of 66 pesticides and 5 mycotoxins regulated by the State of California in medium-chain triglyceride (MCT) oil cannabis tinctures. The limits of quantitation (LOQs) of all of the pesticides and mycotoxins were well below California state action limits of these analytes in cannabis-based non-inhalable or edible products. A total of 62 (out of 66) pesticides and 5 mycotoxins were analyzed using LC–MS/MS with an ESI source, and the remaining 4 pesticides were determined using LC–MS/MS with an APCI source. A simple, fast, and cheap acetonitrile solvent extraction method was used for sample preparation to get good recovery and achieve high throughput for this analysis. For late-eluted analytes, a number of internal standards were used to compensate for ion suppression effects from the hydrophobic matrix.

A rapid and sensitive ultrahigh-pressure liquid chromatography tandem mass spectrometry (UHPLC–MS/MS) method was developed to simultaneously determine six plant growth regulators in bean sprouts with a simple preparation. Analyte extraction from samples was effectively performed using liquid–liquid extraction (LLE) by acetonitrile. Chromatographic separation was conducted on a C18 reversed-phase column with gradient elution. The analytes were detected by tandem quadrupole MS after negative electrospray ionization by multiple reaction monitoring. The developed method was validated by testing method specificity, matrix effect, sensitivity, linearity, accuracy, and precision.