Measurement of urinary vanilmandelic acid and homovanillic acid by high-performance liquid chromatography with electrochemical detection following extraction by ion-exchange and ion-moderated partition.
An improved protocol has been developed to isolate homovanillic acid (HVA) and vanilmandelic acid (VMA) from urine with strong anion-exchange resin. The sample is diluted with acetate buffer and passed through a disposable column. HVA, uric acid, and many hydrophobic organic acids are removed with 1.0 M acetic acid--ethanol. Then VMA is eluted with 0.5 M phosphoric acid. Two isocratic mobile phases allow rapid high-performance liquid chromatographic measurement of VMA (5 min) and HVA (8 mins) on a 5-micron ODS column. Selective conditions were developed with dual-electrode coulometric detection to permit specific measurement of VMA, HVA, and internal standards, with less than 5% between-run variation.
D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002852:Chromatography, Ion Exchange / Q000379:methods; D004563:Electrochemistry; D006719:Homovanillic Acid / Q000652:urine*; D006801:Humans; D009447:Neuroblastoma / Q000652:urine; D010648:Phenylacetates / Q000652:urine*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D014642:Vanilmandelic Acid / Q000652:urine*
D010648:Phenylacetates; D014642:Vanilmandelic Acid; D006719:Homovanillic Acid