Analysis of Amino Acids in Soy Isolates and Navy Beans Using Precolumn Derivatization with Phenylisothiocyanate and Reversed-Phase High Performance Liquid Chromatography


  • Presented in part at the 49th Annual Meeting of the Institute of Food Technologists, New Orleans, LA, June 19-22, 1988.

  • North Dakota Agricultural Experiment Station Journal Article No. 0000.

  • The authors thank Dr. H. Klosterman and Mr. L. Cook in the Dept. of Biochemistry, North Dakota State Univ., for permission to use a Waters Workstation for PITC derivatization.


Amino acid analysis of three legume samples using precolumn phenylisothiocyanate (PITC) derivatization and reversed-phase high performance liquid chromatography (RP-HPLC) was compared with literature data or that obtained by the conventional ion-exchange chromatographic (IEC) method. The results indicated that the amino acid profiles obtained by PITC derivatization and RP-HPLC compared fairly well with literature data for soy isolates, and fairly with that obtained by the IEC method for navy beans. Average coefficient of variability of all amino acids determined by the PITC method was 6%. It was not essential to remove lipids (2.1%) in navy beans prior to acid hydrolysis and PITC derivatization for the analysis of amino acids.