title: Early identification of isovaleric aciduria using photodiode array detection for liquid chromatographic profiling of urinary carboxylic acids.
abstract: The 190 nm high performance liquid chromatographic photodiode array profiling of the urinary carboxylic acids of the first urine of a newborn affected with isovaleric aciduria afforded an abnormal peak at 27.8 min. This peak was greatly increased in the carboxylic acid profiling of the 14 h urine sample from the same infant. Isolation of this peak by fraction collecting; solvent extraction of the eluent; trimethylsilyl derivatization of the residue and gas chromatographic/mass spectrometric analysis identified the compound as isovalerylglycine. Correlation of the 190 nm absorbance of isovalerylglycine (y) with concentration (x) afforded a least squares curve: y = 476.4x-13.72 (r = 0.99); run-to-run variation 6.92%; day-to-day variation 8.88% with a minimum detectable concentration of 25 micrograms/ml.
mesh_terms: D002264:Carboxylic Acids / Q000652:urine*; D002851:Chromatography, High Pressure Liquid; D045782:Hemiterpenes; D006801:Humans; D013058:Mass Spectrometry; D010421:Pentanoic Acids / Q000652:urine*; D013056:Spectrophotometry, Ultraviolet; D014631:Valerates / Q000652:urine*
chemical_list: D002264:Carboxylic Acids; D045782:Hemiterpenes; D010421:Pentanoic Acids; D014631:Valerates; C008216:isovaleric acid