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 capabili ties for both the ion isolation and collision-induced dissociation ste ps in GC-MS-MS. With these improvements, benchtop GC-MS-MS can improve the detection limit of mass spectrometers for low-level target compou nds in complex matrices. With this brief study of malathion, we demons trate (I) excellent sensitivity, (2) wide dynamic range and (3) effect ive elimination of chemical background. GC-MS-MS is compared to standa rd GC-EI-MS and GC-CI-MS techniques for the analysis of malathion in o range extract. GC-MS-MS is the most selective and sensitive technique, virtually eliminating the background interference. Product ion mass s pectra are invariant across the chromatographic peak and excellent lin earity is observed over a range from 2.2 pg/mu l to 2.2 ng/mu l for ma lathion. Detection limit by GC-MS-MS was estimated at 0.5 mu g/kg in t he orange oil matrix (S/N = 5).