摘要：The ninhydrin reagent for use in the quantitative determination of amino acids separated by paper chromatography was reexamined and modified, and the conditions under which the reagent could be used most advantageously were determined. The potency of the ascorbic acid contained in the reagent was stabilized by the use of 2% aqueous solution of metaphosphoric acid, and the blank test value and the range of variation in the determined value were minimized. This modified method surpasses the original in that it is less expensive, less sensitive to ammonia, and easier to use, than the latter.
