Comparison Between Free Amino Acid Levels in Plasma Deproteinated with Picric Acid and with Sulfosalicylic Acid.

A comparative study of 20% sulfosalicylic acid and of 1% picric acid in precipitating plasma proteins before analysis for free amino acids by ion-exchange chro-matography showed that both methods give values comparable in precision and accuracy. The sulfosalicylic acid method is less time-consuming, and requires fewer manipulations.