DETERMINATION OF ENVIRONMENTAL CONTAMINANTS USING AN ELECTROSPRAY INTERFACE COMBINED WITH AN ION TRAP MASS-SPECTROMETER

A commercial electrospray source was interfaced with an ion trap mass spectrometer (ITMS) to analyze compounds of environmental concern. The system was optimized to achieve maximum sensitivity. Ions were injected into the trap, which was held st a helium pressure of 3 X 10(-4) Torr, at a q(z) value of 0.1-0.15. Collisional activation of ions generated from pesticides and dyes was achieved in the electrospray transport region by adjusting the repeller voltage. The ion trap was also used to provide structural information about the [M + H]+ ions formed. Collision-induced decomposition spectra from both processes were similar. Collisional activation in the electrospray transport region required high sample purity. The MS/MS spectra generated in the ITMS were less susceptible to interference from matrix components; however, the acquisition of the MS/MS spectra required extensive instrument setup. Liquid chromatography/electrospray-ITMS was used to analyze a spiked water sample directly. Full-scan electrospray CID spectra were obtained on 10-30-pg quantities of material, resulting in low ppb detection,