Using Chemical Derivatization to Determine the Human Urinary Acidic Catecholamine Metabolites Quantitatively by Liquid Chromatography/Electrospray Ionization-Tandem Mass Spectrometry

Based on a 4,6-dimethoxy-2-(methylsulfonyl)pyrimidine (DMMSP) labeling reagent, a sensitive method to determine acidic catecholamine metabolites homovanillic acid (HVA), vanillymandelic acid (VMA), 3,4-dihydroxymandelic acid (DOMA) and 3,4-dihydroxyphenylacetic acid (DOPAC) has been developed using simple chemical derivatization with liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS). Acidic catecholamine metabolites were converted to stable 4,6-dimethoxypyrimidinyl (DMP) derivatives by one-step derivatization. Because of bulky DMP group(s) introduced into the structures of these metabolites, subsequent analysis by LC/ESI-MS/MS in positive ionization with multiple reaction monitoring (MRM) allowed specific detection of DMP derivatives of these metabolites with a wide linear relationship range. The limits of detection were in the range of 1-5 ng/mL. The mean recoveries determined were 100.2%-104.4%. Both relative standard deviation and error for intra- and inter-day measurements were less than 10% for acidic catecholamine metabolites. This strategy enabled accurate and specific determination of acidic catecholamine metabolites in human urine.