The Colorimetric Estimation of Plasma Amino Nitrogen with DNFB

Abstract

Abstract A simple procedure for the estimation of plasma amino nitrogen based on the reaction of amino groups with 2,4-dinitrofluorobenzene (DNFB) and subsequent measurement of the dinitrophenyl (DNP) amino derivatives at 420 mµ is presented. Elevated concentrations of bilirubin, hemoglobin, and the major nonprotein and nonamino acid nitrogen components of plasma do not seriously interfere. The proposed procedure compares favorably with a corresponding ninhydrin technic for plasma amino nitrogen. The mean plasma amino nitrogen values and range for a group of adults (age 18-50 years) by the proposed method is 5.56 mg./100 ml. (3.6-7.0 mg./100 ml.) compared to 4.12 mg./100 ml. (3.6-5.2 mg./100 ml.) for a group of children (age 2-10 years). Values from a group of children with sickle cell anemia showed no significant variance with the normal population. Optimum conditions for quantitation of plasma amino nitrogen along with other procedural parameters are presented.