RT Journal Article SR Electronic T1 Estimation of alpha-amino nitrogen in plasma and urine by the colorimetric ninhydrin reaction JF Journal of Clinical Pathology JO J Clin Pathol FD BMJ Publishing Group Ltd and Association of Clinical Pathologists SP 150 OP 153 DO 10.1136/jcp.17.2.150 VO 17 IS 2 A1 D. M. Matthews A1 G. G. Muir A1 D. N. Baron YR 1964 UL http://jcp.bmj.com/content/17/2/150.abstract AB Methods are described for the estimation of plasma and urine α-amino nitrogen by the colorimetric ninhydrin reaction; in the method for urine, both ammonia and urea are separated by a rapid ion-exchange resin procedure. Two methods of estimation are given; one has the advantage of great simplicity, but involves the use of cyanide; in the other, cyanide is eliminated. Normal values are reported; they correspond well with those obtained by the gasometric ninhydrin method.