Temperature programmed desorption mass spectrometry of organic matrix compounds

Abstract

The desorption of organic matrix compounds from a stainless steel sample probe in vacuum has been studied using temperature programmed desorption (TPD) to learn about their useful lifetimes and stabilities at temperatures and vacuum environments typically used in secondary ion mass spectrometry (SIMS) or fast atom bombardment mass spectrometry (FABMS) of organic samples. Glycerol, thioglycerol, triethanolamine, and 3-nitrobenzyl alcohol were chosen for study since they are commonly used as matrix compounds in FABMS. For all matrix compounds studied, molecular species desorb within a relatively narrow temperature range which is unique for each matrix, but consistent with the known liquid–gas phase transition temperature of each compound. For one compound (glycerol), additional species desorb which are attributed to decomposition of the compound during TPD. These results suggest that for each matrix compound used in SIMS or FABMS an optimum useful temperature range can be defined. The ultimate performance of each matrix, however, may also be affected by the thermal stability, which varies for the compounds studied in this work.