Analysis of urinary catecholamines: An improved auto-analyzer fluorescence method

Abstract

An improved automated procedure for analysis of urinary catecholamines, based on the trihydroxyindole reaction is presented. The steps of the analysis and the significance of the reagents are studied systematically. Changes of the catecholamine contents during storage of urines and eluates is investigated. The Chromatographic step is speeded up. Concentrations of chemicals, pH and reaction times are made optimal for maximal sensitivity and best differentiation between adrenaline and noradrenaline. The result is a reliable, sensitive and rapid semi-automated technique for quantitative differential analysis of urinary adrenaline and noradrenaline. The capacity of both steps of the analysis is high. Thus, 40 urines can be chromatographed per day or 90 eluates can be analysed per day by one laboratory technician. The method has a high reproducibility and good specificity. However, high amounts of methyldopa or l-dopa interfere with the analysis. A rapid and simple method is described for detecting the presence of interfering substances in urine from patients given methyldopa or l-dopa.