The plasma chromatograph as a qualitative detector for gas chromatography

A plasma chromatograph can function as a very sensitive, qualitative detector for a gas chromatograph. Sample components in a gas chromatographic peak can be detected in quantities of 106 to 1012 g and be identified by their characteristic positive and negative mobility spectra. The types of reference mobility spectra produced by alkanes, aromatics, esters, halogenated and nitrated compounds have been previously reported. This study presents the reference mobility spectra produced for benzoic and isomeric phthalic acids and some of their esters. All these compounds display strong positive mobility spectr containing abundant ions of the MH . (M :H2O)H-(M)NO and (M R)H type. Benzoic acid, benzaldehyde and terephthalic acid give no negative mobility spectra, while the other compounds and esters show negative mobility spectra whose prominent ions are of the M or (M H2O) type.