COLUMN CHROMATOGRAPHIC ANALYSIS OF NEUTRAL AND ACIDIC AMINO ACIDS USING LITHIUM BUFFERS

An evaluation has been made of recent improvements in automatic column chromatographic amino acid analysis that separate asparagine and glutamine without adversely affecting the resolution of other amino acids. Lithium citrate buffers, pH 2.80 and 3.82, a column temperature of 37°, and flow rates of 50 ml/hr for the buffers and 25 ml/hr for the ninhydrin reagent were employed. The total run time was 7 hr 30 min. The majority of the results of the earlier report were confirmed although slightly different conditions were used. The major difference in the current studies was the finding that α-aminoadipic acid was consistently eluted before proline, and citrulline, before α-amino-ηn-butyric acid. In the previous report the relative positions of α-aminoadipic acid and citrulline were interchanged. © 1968.