An Improved Fluorometric Method for the Determination of Tryptophan in Urine Using Sephadex G-10 Extraction

Abstract

Substances interfering with the fluorometric determination of tryptophan (Try) were removed from the urine by a Sephadex G-10 column. Try was eluted with 0.1 N HCI and H₂O and determined by the plasma method of Denckla & Dewey instead of their more laborious extraction method used for urine analyses. There was a fairly good correspondence between the urine method of Denckla & Dewey as modified by Lehmann, and the Sephadex method. Recoveries were within the limits ± 10 per cent for 50–500 nanomols Try added to urines and the reproducibility was good. The method was especially useful when combined with the analysis of 5-hydroxytryptamine and 5-hydroxyindole acetic acid eluted from the same columns.

Key Words:

• Sephadex G-10
• tryptophan in urine