Ascorbic acid: an unstable ninhydrin-positive urinary constituent running with valine in a commonly used screening system.
Large amounts of ascorbic acid occur occasionally in the urine of children being investigated for possible inherited metabolic disease and may give a positive ninhydrin reaction after thin-layer chromatography. As this compound is unstable in urine and runs with valine in a solvent system commonly used for preliminary screening, it is a possible source of confusion.
D001205:Ascorbic Acid / Q000652:urine*; D002648:Child; D002675:Child, Preschool; D002855:Chromatography, Thin Layer; D005820:Genetic Testing; D006801:Humans; D007223:Infant; D008661:Metabolism, Inborn Errors / Q000175:diagnosis*; D009555:Ninhydrin; D013048:Specimen Handling; D014633:Valine / Q000652:urine
D009555:Ninhydrin; D014633:Valine; D001205:Ascorbic Acid