CAPILLARY ZONE ELECTROPHORETIC SEPARATION OF HOMOVANILLIC AND VANILLYLMANDELIC ACIDS

Capillary zone electrophoresis with untreated fused-silica capillaries and acetate buffer was evaluated for the separation and analysis of catecholamine metabolites. Homovanillic acid and vanillylmandelic acid, which are excreted in abnormally elevated levels in the urine of patients with neuroblastoma, were separated from other possible catecholamine metabolities, using a 200 mM acetate buffer at pH = 4.10. The high buffer concentration was necessary to minimize the peak tailing resulting from analyte-capillary wall interactions. The concentration detection limits of the injected sample at 214 nm were 36 mg/L for vanillylmandelic acid and 64 mg/L for homovanillic acid.