High-performance liquid chromatographic/mass spectrometric and high-performance liquid chromatographic/tandem mass spectrometric analysis of carbamate pesticides.

Abstract

The thermospray ionization mass spectra of selected carbamate pesticides were obtained using both single-stage and triple-stage quadrupole mass spectrometry in conjunction with high-performance liquid chromatography. With the use of the single-quadrupole mass spectrometer and ammonium acetate as the mobile phase, enhanced sensitivity for the analytes of interest was obtained by monitoring the relatively intact [M + 1]+ or [M + 18]+ adduct ions. Further structural characterization of the carbamates was not readily obtainable owing to the lack of diagnostic bond cleavages. The single-stage quadrupole analyses were therefore complemented by triple-stage quadrupole analyses. Here, collisionally activated daughter ion spectra exhibited structure-specific fragmentations. In addition, the enhanced selectivity and specificity provided by tandem mass spectrometry allowed use of the technique as a rapid screening tool for carbamates without the need for the chromatographic separation step.