A Method For The Trace Analysis Of 175 Pesticides Using The Agilent Triple Quadrupole GC/MS/MS

By Philip L. Wylie and Chin-Kai Meng, Agilent Technologies, Inc.

A GC/MS/MS multiple reaction monitoring (MRM) method has been developed on the Agilent 7890A/7000A GC triple quadrupole mass spectrometer system (GC/QQQ) for 175 commonly analyzed pesticides. Numerous fruit and vegetable extracts were analyzed by this method and by a GC single quadrupole mass spectrometer (GC/Q) for comparison. The GC/Q was operated in the selected ion monitoring (SIM) mode and in the scan mode. Scan results were evaluated using Agilent's Deconvolution Reporting Software (DRS) with the RTL Pesticide and Endocrine Disruptor Database. The GC/Q instrument was equipped with a Multimode inlet and injections of 5 µL were made in the cold splitless mode. These were compared to 1 µL injections of the same extracts on the GC/QQQ. The GC/QQQ was found to be far more sensitive and selective than either GC/Q approach, primarily because there is much less interference from co-extracted matrix. There is, however, still a need for GC/Q methods that use DRS to screen for more than 900 pesticides and other contaminants since the GC/QQQ in the MRM mode is only for target compound analysis.