Direct measurement of homovanillic, vanillylmandelic and 5-hydroxyindoleacetic acids in urine by capillary electrophoresis

Separation conditions in CE, with a neutral coated capillary and reversed p olarity, have been optimised to make direct measurement of vanillylmandelic acid, homovanillic acid and 5-hydroxyindoleacetic acid possible in urine s amples without pre-treatment. The method developed has been validated, pres enting adequate parameters for linearity, accuracy and precision. Detection limits range from 0.03 to 2.5 mu M. Finally the method has been applied to urine samples taken from patients, both adults and children, in hospital. Some of them were also measured by immunoassay and HPLC-electrochemical det ection and results have been compared. (C) 2000 Elsevier Science B.V. All r ights reserved.