CAPILLARY GAS-CHROMATOGRAPHIC INTRODUCTION OF ENVIRONMENTAL COMPOUNDSINTO A TROCHOIDAL ELECTRON MONOCHROMATOR MASS-SPECTROMETER

A gas chromatograph was interfaced to an electron monochromator/quadru pole mass spectrometer. The new system was tested for the analysis of environmental compounds. Detection sensitivity for hexachlorobenzene ( HCB) through the gas chromatograph was 5 pg or better, and a mass-reso lved molecular ion cluster for this compound on the fly was achieved w ith 10.8 ng of sample. An ion chromatogram was obtained using 45 ng of Aroclor 1254, and the extract from a trout muscle sample recently col lected in the Arctic yielded a chromatographic profile Similar to that observed using negative ion chemical ionization mass spectrometry A m ixture of HCB and 2,4,6-trinitrotoluene (TNT) were shown to be disting uishable at 2.4-eV electron energy. The energetics of regioselective f ragmentation of [4-(NO2)-N-15] TNT by dissociative electron capture ca n be determined on the By. Complete negative ion gas chromatography/ma ss spectrometry (GC/MS) spectra were obtained for hexafluorobenzene an d TNT by simultaneously ramping the electron energy from -2 to 15 eV a nd scanning the mass over a 200-Da range.