USE OF 2,4-DINITROPHENYLHYDRAZONE OF GLYOXYLIC-ACID FOR THE DETERMINATION OF GLYOXYLIC-ACID BY THE CHROMATOGRAPHIC-SPECTROPHOTOMETRIC METHOD AND BY DIFFERENTIAL-PULSE POLAROGRAPHY

Two different methods (one based on chromatography and spectrophotomet ry and the other on polarography) have been developed for the determin ation of glyoxylic acid in the form of a derivative with 2,4-dinitro p henylhydrazine (DNPH . GA). The TLC method allows the separation of tw o DNPH . GA isomers (''trans'' and ''cis''). Spectrophotometric:measur ements of the eluents of the separated compounds (lambda = 360 nm) all ow the determination of GA within the range from 4 to 30 mu g. Using d ifferential pulse polarography, the conditions of DNPH . GA formation were examined. The reduction peak of this derivative (E(p) = -0.430 V) , observed by dpp, was used to develop a polarographic determination o f GA within the concentration range from 1 . 10(-4) to 7 . 10(-4) mol/ l.