Quantitative determination of 3-methoxy-4-hydroxyphenylethyleneglycol and its sulfate conjugate in human lumbar cerebrospinal fluid using liquid chromatography with amperometric detection

A sensitive and direct reversed-phase liquid chromatographic method with amperometric detection was developed for the determination of 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG). The concentrations of the free and sulfate conjugate of MHPG were measured in human lumbar cerebrospinal fluid. All samples were preconcentrated by extraction with ethyl acetate. Deconjugation of the sulfate form of MHPG was achieved by enzymatic hydrolysis with sulfatase. Peaks were identified on the basis of chromatographic behavior, ratio of responses at several oxidation potentials and the stopped-flow UV spectra of the collected fractions. The free MHPG content of 20 cerebrospinal fluid samples ranged between 0.720 and 19.51 ng/ml with the mean of 5.126 ± 4.652 (S.D.) ng/ml. The sulfate conjugate of MHPG in 12 samples of cerebrospinal fluid ranged between 0.08 and 0.850 ng/ml with the mean value of 0.2365 ± 0.2269 (S.D.) ng/ml. Although our results correlate well with the literature values, no attempt was made to interpret the quantitative data since samples were obtained from routine, diagnostic testing of patients admitted to the medical or neurologic services at the Mount Sinai Hospital.