Clinical Chemistry, Vol 18, 621-624, Copyright © 1972 by the American Association for Clinical Chemistry

Accelerated Single-Column Procedure for Automated Measurement of Amino Acids in Physiological Fluids

¹ Clinical Laboratory and Department of Pathology, Stanford University Medical Center, Stanford, Calif. 94305.

This automated analytical procedure involves a single 27 cm x 0.9 cm column of UR-40 resin and a stepwise elution with sodium citrate buffers. In one sequential run more than 35 acidic, neutral, and basic amino acids can be measured in physiological fluids in 6 h. Thus, a minimum of three runs can be performed per 24 h, during which the analysis can be unattended. Increased sensitivity allows the use of small samples (such as 0.2 ml of plasma ultrafiltrate). Picric, sulfosalicylic, or perchloric acids are not required for sample preparation. Ultrafiltration under nitrogen pressure is used instead and gives a clear solution containing the free amino acids. Ultrafiltration rate is 1 ml per 1.5 h; 10 samples can be processed simultaneously.