Determination of certain amino-acids by ninhydrin oxidation to volatile aldehydes

Publisher Website
Google Scholar
Abstract
A method based on the quantitative formation of volatile aldehydes from [alpha]-alanine, valine, leucine, isoleucine and possibly other isomers, phenylalanine and methionine (R.Ch(NH2).COOH [long dash] R.CHO) has been used for the quantitative micro-detn. of these amino-acids as a group ("volatile aldehyde amino-acids"). The mixture of amino acids is treated with ninhydrin in the Lieb-Zacherl apparatus, and the volatile aldehydes are driven by a current of air over into a bisulphite soln. The bisulphite is titrated with O.01[image]-iodine soln. With other amino-acids found in proteins no formation of volatile aldehydes was detected. Acetaldehyde can be detd. separately from the mixture of aldehydes. Thus it is possible to determine by means of volatile aldehydes (a) the above group of amino-acids, and (b) alanine. If phenylalanine and methionine are detd. separately by specific methods, valine, leucine and isoleucine remain to be detd. Separate detn. of the aldehydes formed from them has not yet been successful.

This publication has 1 reference indexed in Scilit: