Simultaneous determination of vanillylmandelic, homovanillic and 5-hydroxyindoleacetic acids in human urine by thin layer chromatography.

A TLC method for the simultaneous analysis of vanillylmandelic, homovanillic and 5-hydroxyindole-3-acetic acids in urine is described. The sample is cleaned up through a cyano minicolumn and extracted with diethyl ether. The acids are resolved by high-performance TLC, visualized by Folin Ciocalteau reagent and quantificated by densitometry at 600 nm with beta-(4-hydroxy-3-phenyl) acetic acid as the internal standard.