LAUSR

Abstract Field-induced fragmentation (FIF) spectra were obtained for mobility isolated protonated monomers of volatile organic compounds from six chemical families from 130 to 157 Td in the reactive stage-of a tandem ion mobility spectrometer at 98 °C. The extent of fragmentation at ambient pressure increased linearly with field strength for n-alcohols of carbon number 3 to 5, for n-akyl acetates of carbon numbers 4 to 11, and for n-aldehydes and ethers not previously fragmented at 129 Td and 93 °C. Efficiencies of fragmentation at 157 Td ranged from 57 to 100% for n-alcohols, 25–100% for n-alkyl acetates of carbon numbers 5 to 8 (10–29% for carbon numbers 9 to 11), 29–84% for ethers of carbon number 8 and below, and 7–57% for n-alkanes of carbon number 7 to 11. Multiple, low mass ions in FIF spectra were attributed to second and third levels of fragmentation with identical reduced mobility coefficients characteristic of a chemical class. Differences in fragment ion patterns between chemical classes were attributed to structural information from field-induced fragmentation. Classification by chemical class using neural networks was significantly improved for acetates and aldehydes with increased fragmentation at 157 Td. Spectra without fragmentation were poorly classified. Models of ion energy within the reactive stage suggested that ions undergoing decomposition were not symmetrically distributed between etched metal grids in the reactive stage.