Determination of -Amino Acid Nitrogen in Urine

Abstract
Summary A modification of the photometric copper phosphate method for determination of α-amino acid nitrogen in urine has been presented. A comparison of results obtained in urines by the copper phosphate, naphthoquinone and gasometric-ninhydrin methods indicates that the specificity of the copper phosphate and naphthoquinone methods is materially improved by preliminary isolation of the amino acids on an ion exchange column.