Quantitative determination of keto-acids by paper partition chromatography

A simplified method for the quantitative determination of keto-acids by means of paper chromatography of their 2,4-dinitrophenylhydrazones is reported. 1. 1. The identification of these compounds on the filter paper is discussed, especially of those compounds which give more than one spot. 2. 2. The method is described in detail, espicially with regard to the pyruvic and α-ketoglutaric acid content in biological material. The recovery of these two keto-acids, starting from known aqueous solutions, averages 94%; on the basis of these results a standard curve can be drawn. According to this curve, recovery from deproteinized extracts of liver and blood averages 91.6% for pyruvic acid and 96.7% for α-ketoglutaric acid. 3. 3. Using this method the pyruvic and ketoglutaric acid content of rat blood, muscle, liver and brain is estimated.