A selenium-selective chromatoraphic detector based on isotope cluster

A selenium-selective chromatograhic detector based on mass spectrometry is described. Full mass spectra are collected continously from the gas chromatographic effuent. A computer program then searches the spectra for the naturall-occurring selenium isotope cluster, indicating which spectra in the data set are most likely to contain those clusters. The device involves a selective data-reduction technqiue, as opposed to a selective data-collection process; it therefore possesses some useful advantages. The method was tested on the EPA/NIH Mass Spectral Data Base and on the analysis of trimethylsilylated amino-acid mixtures including selenomethionine.