Isotachophoresis of urinary purines and pyrimidines: the use of spacers and enzymes for identification.

An isotachophoretic system is described for the separation and identification of urinary purine and pyrimidine bases and nucleosides. For a better discrimination and interpretation of the UV profiles, well-defined non-UV-absorbing substances were introduced as spacers. Treatment of urine samples with purified enzymes before analysis resulted in specific shifts in the metabolite profiles, providing a sensitive and specific means of identifying a number of metabolites. With an injected volume of 3 microliters (untreated urine diluted 1:5) the present method allows reproducible separations within 20 min of at least twenty different nucleosides and bases.