A reversed-phase high-performance liquid chromatographic method has been developed for the analysis of purine and pyrimidine bases, uric acid and nucleosides largely relating to the purine synthetic and degradation metabolic pathways, with particular attention to the separation of hypoxanthine, xanthine and guanine. Complete separation and quantitation of the purines has been accomplished in the nanogram-microgram scale on conventional 4.6 mm I.D. columns with a standard gradient HPLC instrumentation as well as on 1 mm I.D. microbore columns with a dedicated isocratic micro-HPLC system using a dioxane-sodium acetate buffer. For the definite identification of components in excreta of ticks a GC-MS method has been described involving formation and GC of the trimethysilyl derivatives on a 25-m DB-5 column directly coupled with an ion trap detector. The methods are demonstrated on the analysis of the purine metabolites having an assembly pheromone effect on argasid ticks.