Absolute, Unambiguous Ultramicro-analysis of Metabolites present in Complex Biological Extracts

Abstract

THE analysis of substances of biogenic interest is usually difficult and often ambiguous because the metabolite of interest is usually present at low concentration in a complex mixture. Quantitation usually proceeds via pre-fractionation (organic solvent extraction, ion exchange or absorption), chromatographic separation and then a relatively specific chromogenic or fluorogenic reaction either directly on the chromatogram or, after elution, in solution. The certainty of identification using these, or variants of these, procedures is limited. This is particularly so in the field of biochemical psychiatry where over the past few years there have been numerous examples of chromatographically separated chromogenic factors which have meant different things to different people (further details in ref. 1). We present here preliminary data on the use of a new technique—the so-called “integrated ion current (IIC) technique”—involving the high resolution double focusing mass spectrometer (in our case, the MS9 manufactured by Associated Electrical Industries).