Optimization of Negative Ion Chemical Ionization Mass Spectrometry for Explosives for Two GC/MS Instruments from Different Manufacturers

摘要

Varying reagent/collision gas flow rates (source pressures) yielded similar effects on explosives sensitivities for the two instruments. Source temperatures affected both sensitivities of explosives as well as their mass spectra for both instruments. Optimal sensitivities ocurred at different source temperatures for the two instruments. Higher source temperatures consistently shifted relative abundances to lower m/z fragment ions. The optimal injector temperature for instrument 2 was determined to be 250 deg C. Injector temperatures above this optimum resulted in complete degradation of some of the energetic compounds, while lower temperatures yielded insufficient volatilization of the explosives and related compounds.