Gas chromatographic analysis of pyruvic and .alpha.-ketoglutaric acids

Abstract

Simplification of apparatus is possible in titrations of relatively larger amounts of calcium. Manual titrations can be carried out using a regular pH meter as the indicator. Sharp end points are obtained if 10_2M or stronger titrants are used. A color indicator is less suitable because strict requirements are imposed on the stoichiometry of the titrant because the pH of the sample is not allowed to change significantly during the titration.

Propionyl-CoA carboxylase deficiency with overflow of metabolites of isoleucine catabolism at all levels

“…A quantitative determination was performed in a sample from the second day of the loading experiment. The oxoacid was extracted as a quinoxalone, and this compound was subjected to gas chromatography after trimethylsilylation (Hoffmann and Killinger, 1969). We found 0.72mmoles/1 or 0.36mmoles/g creat.…”

Single determination of α-ketoglutaric acid and pyruvic acid in beer by HPLC with UV detection

“…2. 11,15 Quinoxalines-or to be more precise for this case, hydroxyquinoxalines-are compounds that can be easily separated by liquid chromatography and detected by UV spectrophotometry. 24,26 When this derivatization reaction is applied to real samples, usually the major problem is finding an effective prior separation or clean up step 3 since ''dirty'' samples like beer should not be directly injected into modern chromatographic columns.…”

“…14 The first analytical methods for determination of a-ketoacids arose nearly 50 years ago with the development of gas chromatography (GC). 15,16 Later, methodologies using fluorescence detection were also published (either using derivatization agents 2,3,17 or using an enzymatic mechanism 18,19 ) and, more recently, using capillary electrophoresis. 20 Polarography has also been applied in the determination of KA and PA; though very sensitive the signal distinction between KA and PA is almost impossible.…”