Kevin Bennett Hood College, Frederick, MD Office: 301-696-3682 FAX: E-mail: bennett@hood.edu Job Title: Assistant Professor Ph.D. in Analytical Chemistry from the University of Tennessee at Knoxville

Speaker: Kevin Bennett, Hood College, Frederick, MD

Topic: Deconvolution of Multicomponent Mass Spectra

Place: Building 549, Auditorium, NCI at Frederick, Frederick, MD

Time: Tuesday, September 14, 2004, at 2:00 PM

Abstract: Process mass spectrometry was tested for its ability to simultaneously quantitate mixtures of hydrocarbons that included up to six components. Simultaneous analysis is based on the assumption that the concentration-weighted electron ionization mass spectrum of the mixture is a linear combination of the spectra of the individual mixture constituents. Quantitation accuracy and precision were found to decrease as the number of components in a mixture and the spectral similarity of those components increased. Quantitation performance varied among tested systems, with those mixtures containing multiple isomers proving to be the most difficult to quantitate.

Selection of which ions to monitor (parameterization) was critical to optimum analysis accuracy, precision, and speed. An empirical parameterization algorithm based on comparison of reference spectra of mixture components was developed for ion selection. Empirical algorithm parameterizations gave analysis accuracy and precision values statistically equal to, or better than, all-mass parameterizations. This study of simultaneous analysis of isomers may expand the applicability of quantitative process mass spectrometry to a wider range of process mixtures.