Multiple ion detection: A new tool for neurochemistry and biological psychiatry

Abstract

Publisher Summary Multiple ion detection or mass fragmentography is a technology capable of meeting high specificity and sensitivity to measure the small concentrations of putative neurotransmitters, their precursors and metabolites in spinal fluid of man. The technique consists of the use of mass spectrometer for the detection of only certain ions preselected for their m/e values. The mass spectrometer focussed simultaneously upon three fixed nominal mass charge ratios (m/e) provides a sensitive and extremely specific detector for a gas chromatograph. By combining gas chromatography and mass, the chemical identity of a compound can be established and concentration of 10–100 femtomoles per sample can be measured. Multiple ion detection becomes a quantitative method by the addition to the sample of appropriate deuterated internal standards. Knowledge of the mass spectra and of the fragmentation patterns of a compound and of its deuterated analog used as internal standard is necessary to perform the appropriate focusing of the instruments.