Lysinoalanine determination in sodium caseinate using the LKB Alpha Plus Amino Acid Analyser.

摘要

Adaptation of the LKB Alpha Plus Amino Acid Analyser to separate and detect lysinoalanine (LAL) in caseinates is described. The separation of LAL was achieved by cation exchange followed by post-column derivatization with ninhydrin. The effect on the separation of varying the pH and molarity of Na+ in the mobile phase and the column temperatures was investigated. An isocratic system using 0.2 M Na+ in a citrate buffer at pH 4.9-5.5 and column temperature of 48-56鳦 was the most suitable for the separation of LAL. The method was validated by achieving a recovery of 100?%, limit of detection of 20 ppm and a repeatability relative s.d. of 7%.