Determination of urinary normetanephrine, metanephrine, and 3-methoxytyramine by liquid chromatography, with amperometric detection.
We describe a sensitive procedure for measuring the basic catecholamine metabolites--normetanephrine, metanephrine, and 3-methoxytyramine--in urine by use of liquid chromatography, with electrochemical detection. These substances are isolated from hydrolyzed urine by passage through small ion-exchange columns and then pre-concentrated by a rapid set of solvent extractions before being injected onto the liquid-chromatographic column. Concentration and instrumental response are linearly related to 2.0 mg/liter for all three compounds, and practical lower detection limits are about 20 micrograms/liter for actual urine samples. The high selectivity that accrues from the combination of the extraction procedure, high-performance liquid chromatography, and electrochemical detection makes this procedure suitable for quantitative studies of catecholamine metabolism. A set of six samples can be taken through the extraction procedure in parallel in less than 2 h; once prepared, the extracts can be analyzed at a rate of three per hour.
D000328:Adult; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods; D004298:Dopamine / Q000031:analogs & derivatives; D004563:Electrochemistry; D004837:Epinephrine / Q000031:analogs & derivatives*; D006801:Humans; D008297:Male; D008676:Metanephrine / Q000302:isolation & purification / Q000652:urine*; D009647:Normetanephrine / Q000302:isolation & purification / Q000652:urine*; D014439:Tyramine / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000652:urine
D009647:Normetanephrine; D008676:Metanephrine; C001746:3-methoxytyramine; D004298:Dopamine; D014439:Tyramine; D004837:Epinephrine