Software-based mass spectral enhancement to remove interferences from spectra of unknowns.

ABSTRACT

Gas chromatography-mass spectrometry data from the analysis of complex environmental samples were converted into ASCII text and imported into a personal computer spreadsheet. A macro was written to perform mass spectral enhancement by statistical and mathematical procedures to separate the spectra of compounds of interest from interfering mass spectral responses, such as those of broadly eluting hydrocarbons. The extracted mass spectra were compared to reference spectra, with the result that usually 80-90% of the ions common to those in the reference spectra were successfully extracted by using this method. This procedure improved mass spectral quality and the ability of the data system to perform successful library searches. The fitted quality parameters showed systematic improvements after the data were subjected to the spectral enhancement procedures. These procedures could help to identify unknowns by separating their spectra from other signals, such as those of background aliphatic hydrocarbons.