HPLC method for measurement of purine nucleotide degradation products in cerebrospinal fluid

We describe a convenient method for the separation and quantification of xanthine, hypoxanthine, and uric acid in 20 microL of cerebrospinal fluid (CSF) with use of HPLC and ultraviolet detection. The analysis is performed on a Sepharon SGX C18 column and the elution system consists of potassium phosphate buffer, pH 5.1, with 20 mL/L methanol. The lower limit of detection was 4 pmol for hypoxanthine and xanthine and 6 pmol for uric acid. Analytical recoveries of purine metabolites ranged from 98.6% to 102.9%. The intra- and interassay CVs were <3%. The applicability of the method is illustrated with the determination of micromolar concentrations of xanthine, hypoxanthine, and uric acid in CSF samples obtained from 113 patients with various neurological disorders.