title: Prepurification and derivatization of alpha-keto acids using hydrazide gel. Application in gas chromatography and gas chromatography--mass spectrometry.
mesh_terms: D002849:Chromatography, Gas; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D006834:Hydrazines; D007651:Keto Acids / Q000097:blood / Q000302:isolation & purification* / Q000652:urine; D008375:Maple Syrup Urine Disease / Q000097:blood; D010661:Phenylketonurias / Q000652:urine
chemical_list: D006834:Hydrazines; D007651:Keto Acids