A spectrophotometric method for simultaneous determination of protein-bound hexoses and fucose with a mixture of L-cysteine and phenol

A very suitable spectrophotometric method for simultaneous determination of protein-bound hexoses and fucose is presented. A mixture of L-cysteine and phenol in sulfuric acid was used as reagent, whereas absorption measurements were carried out at two wavelengths, namely at 398 nm for fucose and 490 nm for hexoses determination. Optimum conditions for the application of the method were established, special attention being paid to the possible interference of fucose determination with that of hexoses, and vice versa. The proposed method was applied to the determination of hexoses and fucose in serum glycoproteins and seromucoids. The method was found to be very practical enabling a simultaneous determination of both kinds of carbohydrates; moreover, it was proved to be more sensitive and specific in comparison with methods commonly used for individual determination of fucose with L-cysteine and hexoses with phenol.