title: Urinary 4-hydroxy-3-methoxymandelic (vanillylmandelic) acid, 4-hydroxy-3-methoxyphenylacetic (homovanillic) acid, and 5-hydroxy-3-indoleacetic acid determined by liquid chromatography with electrochemical detection.
abstract: We describe a simple liquid-chromatographic assay of urinary 4-hydroxy-3-methoxymandelic (vanillylmandelic) acid, 4-hydroxy-3-methoxyphenylacetic (homovanillic) acid, and 5-hydroxy-3-indoleacetic acid with electrochemical detection, with direct injection of the sample. The first two analytes are measured simultaneously; 5-hydroxy-3-indoleacetic acid is measured separately. Chromatographic conditions for assay of the three were: column temperature, 65 and 60 degrees C; mobile phase, potassium phosphate buffer (0.2 mol/L, pH 3.0) for 6 min, then potassium phosphate buffer plus acetonitrile (9/1 by vol) for 20 min; flow rate, 0.7 mL/min; oxidation potential, 600 and 450 mV vs an Ag/AgCl reference electrode; and sensitivity, 40 and 160 nA at full scale. Values so obtained agreed well with those obtained for samples that were first solvent-extracted.
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004563:Electrochemistry; D006719:Homovanillic Acid / Q000302:isolation & purification / Q000652:urine*; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000302:isolation & purification / Q000652:urine*; D010648:Phenylacetates / Q000652:urine*; D012997:Solvents; D014642:Vanilmandelic Acid / Q000302:isolation & purification / Q000652:urine*
chemical_list: D010648:Phenylacetates; D012997:Solvents; D006897:Hydroxyindoleacetic Acid; D014642:Vanilmandelic Acid; D006719:Homovanillic Acid