Spectrophotometric quantification of glycine in serum and urine.

A method for quantitative determination of glycine in serum and urine, involving degradation to formaldehyde with chloramine-T and subsequent measurement by the Hantzsch reaction or chromotropic acid, has been evaluated and modified. The inhibitory effect of some physiological constituents on the analysis is pointed out. We recommend that samples be purified by passage through a column of ion-exchange resin before analysis. Results for urinary glycine obtained by a single-column amino acid analyzer system compare very favorably with those obtained by the proposed spectrophotometric method. Values for free and total glycine and for glycine/creatinine ratios in the urine of a group of infants are presented along with revised data on the concentration of free glycine in serum.