Improved Technique for the Fluorimetric Estimation of Catecholamines

TLDR

The study presents an improved fluorimetric method for estimating catecholamines. The method adds ethylene diamine to the alkali‑ascorbic acid mixture of the trihydroxyindole assay, preventing discoloration and fluorescence loss, with optimal results when the reagent volume exceeds the sample by 1 ml, and it is applied to urine and organ extracts. Fluorescence from adrenaline and noradrenaline standards and alumina eluates remains stable for at least an hour, increases proportionally with sample volumes up to 3 ml, and acidity is crucial for releasing catecholamines from conjugates in urine at room temperature. Authors: E.

Abstract

Abstract E uler U. S. v . and F. L ishajko . Improved technique for the fluorimetric estimation of catecholamines. By the addition of small amounts of ethylene diamine (EDA) to the alkali‐ascorbic acid mixture used in the trihydroxyindole (THI) method the discoloration of reaction mixture and instability of fluorescence can be prevented, allowing blanks to maintain their fluorescence values for several hours. The lutines obtained from adrenaline and noradrenaline standards and from alumina eluates are stable over a period of at least one hour. Optimal fluorescence values are obtained when the volume of alkali‐ascorbic‐acid ‐ EDA exceeds the volume of the sample by 1 ml. A proportional increase in fluorescence is observed with sample volumes up to 3 ml. The technique used for estimation of catecholamines in urine and organ extracts is described. The importance of the acidity for the release of catecholamines from conjugates in urine at room temperature is emphasized.