Fast method for the simultaneous determination of 2-oxo acids in biological fluids by high-performance liquid...

A fast and sensitive method for the single-run quantification of various 2-oxo acids including 2-ketoglutarate, glyoxylate and pyruvate is described. It ensures good separation of peaks with minor interference by other substances. The 2-oxo acid derivatives are measured photometrically at 324 nm after derivatization with phenylhydrazine and subsequent isocratic separation with ethanolic phosphate buffer on a C18 reversed-phase HPLC column. Recovery was found to be complete [range: 96.3 +/- 5.6% (pyruvate) to 104.8 +/- 5.2% (2-ketoglutarate)]. Detection limits ranged from less than 0.1 mumol/l (glyoxylate) to 0.25 mumol/l (2-ketoglutarate and pyruvate). Results for all substances examined showed good linearity with correlations (r2) of equal to or better than 0.998.