Set-up and validation of an adsorptive stripping voltammetric method for kynurenic acid determination in human urine

Validation of an adsorptive stripping voltammetric method for kynurenic aci d determination in urine, was presented. The selection of appropriate valid ation parameters, the design consideration for evaluation and the problem o f endogenous metabolites were discussed. The considered fundamental criteri a for assessing the reliability and overall performance of the method in th e urine matrix were selectivity, linearity and range, limit of quantitation , accuracy, precision and analyte stability. The intermediate precision was also evaluated by means of a full factorial design. An HPLC method with fl uorimetric detection was used as a reference method to assess the accuracy. The analysis in urine required a pH control as pointed out by robustness t esting and the found kynurenic acid concentration in daily urine ranged fro m 5 to 40 mu M. (C) 1998 Elsevier Science B.V. All rights reserved.