High-performance liquid chromatography of biologically important pyrimidine derivatives with ultraviolet--voltammetric--polarographic detection.

High-performance liquid chromatographic separation of a number of biologically important pyrimidine derivatives was studied in the reversed-phase system. Good results were obtained using a C18 alkyl-bonded silica column and an aqueous citrate--phosphate mobile phase of pH 3.5. All eluted components are detected with the UV absorbance detector at 254 nm, whereas the voltammetric detector with a polymeric carbon-paste electrode detects only derivatives containing oxidizable functional groups (amino, mercapto) and the polarographic detector with a mercury electrode only those with reducible groups (nitro, aza). The signal of the electrochemical detectors is proportional to the number of electroactive groups in the solute molecule. The use of two or three detectors in series thus improves the resolution of complex mixtures and facilitates identification.