Colorimetric estimation of uronic acids using 2-hydroxydiphenyl as a reagent

Conditions allowing substitution of 3-hydroxydiphenyl, recommended by N. Blumenkrantz and G. Asboe-Hansen (Anal. Biochem. 54, 484-489, 1973) as a reagent for estimation of hexuronic acids by the much cheaper 2-hydroxydiphenyl were investigated. The absorption maximum of a color product formed by glucuronic acid and 2-hydroxydiphenyl was found to be at 475 nm. Using this wavelength for measurement, and slightly modified reaction conditions, the sensitivity achieved by using both reagents was found to be comparable. The only interference was that of DNA, encountered in nucleic acid-rich unpurified soft tissues extracts.