ANALYSIS OF PESTICIDE-RESIDUES IN FOOD USING GAS-CHROMATOGRAPHY TANDEM MASS-SPECTROMETRY WITH A BENCHTOP ION-TRAP MASS-SPECTROMETER

Recent developments on the Saturn GC-MS system offer enhanced capabilities for both the ion isolation and collision-induced dissociation steps in GC-MS-MS. With these improvements, benchtop GC-MS-MS can improve the detection limit of mass spectrometers for low-level target compounds in complex matrices. With this brief study of malathion, we demonstrate (I) excellent sensitivity, (2) wide dynamic range and (3) effective elimination of chemical background. GC-MS-MS is compared to standard GC-EI-MS and GC-CI-MS techniques for the analysis of malathion in orange extract. GC-MS-MS is the most selective and sensitive technique, virtually eliminating the background interference. Product ion mass spectra are invariant across the chromatographic peak and excellent linearity is observed over a range from 2.2 pg/mu l to 2.2 ng/mu l for malathion. Detection limit by GC-MS-MS was estimated at 0.5 mu g/kg in the orange oil matrix (S/N = 5).