On the separation of α‐keto acid dinitrophenyl‐hydrazones by ionophoresis and their polarographic estimation

Abstract

Rapid separation of synthetic mixtures of the 2,4‐dinitrophenylhydrazone derivatives of α‐keto acids has been effected by paper electrophoresis. The method has been applied to the separation of these derivatives from animal tissues and a polarographic procedure has been devised for the estimation of the hydrazones. Keto acid analyses are presented for organs from normal and tumour‐bearing rats.

Organic Polarography

“…In the -keto acid series the polarographic results for pyruvic acid and for phenylglyoxylic acid have been used extensively to test equations derived for kinetic currents (8, acid and calcium lactate (482); pyruvic acid, oxalacetic acid, and -ketoglutaric acid as the 2,4-dinitrophenylhydrazones after separation by paper electrophoresis (296); -ketoglutaric acid directly (311); and opianic acid in alkaloids (167).…”

Separation of α-Keto Acid Dinitrophenylhydrazones by Paper Electrophoresis and Their Colorimetric Determination

“…While the present paper was in press, Neish (6), advised this author that he also observed component X in some rat blood filtrates. He has named this band Spot X (6). It was observed in the present work that when the dried strips were sprayed with 1N sodium hydroxide spot X gave a light yellow color as opposed to the usual dark red-brown and dark Ilrown color of pyruvic acid and a-ketogutaric acid hydrazones.…”

“…Here separation is didnct. Pyruvic acid hydrazone solutions should not be kept for too many hours a t room temperature; otherwise isomerization and polymerization occurs (1-4, 6,8).…”

“…Neish's values for rat blood (6) are included for comparison. Rabbit blood contains several times more pyruvic acid than the blood of other niamninls.…”

“…The slight positive figure in the absence of cobalt is probably due to the cobalt impurity in the reagent; recovery of added cobalt was 99%. Copper gave no color by itself but reduced the recovery of added cobalt; houever, only a 2% loss occurred with 1 mg. of this metal Larger amounts of copper may be removed by a preliminary extraction with a chloroform solution of dithizone from the ashed solution of sample adjusted to pH 2 (6). determination.…”