title: Enantiomeric determination of DOPA in dietary supplements containing Mucuna pruriens by liquid chromatography/mass spectrometry.
abstract: We developed a simple and rapid liquid chromatography/mass spectrometry (LC/MS) method for the enantiomeric determination of DOPA in dietary supplements containing Mucuna pruriens. L- and D-DOPA were ultrasonically extracted with 1% formic acid aqueous solution. The isolated extracts were analyzed by LC/MS using a Crownpak CR (-) column at 30℃. The mass spectrometer was operated in the positive mode of electrospray ionization, and the mobile phase was aqueous formic acid (pH 2.0). L-DOPA-ring-d3 was used as an internal standard. The method was validated for a dietary supplement spiked with L- and D-DOPA at 50 and 500 μg/g, respectively, and the recoveries of the DOPA enantiomers were between 97.5% and 101.3%. Relative standard deviation values of repeatability and intermediate precision were less than 7%. The method was applied to 14 dietary supplements. L-DOPA was detected in these supplements in the range of 0.88-12.8 mg/unit. D-DOPA was not detected.
authors.affiliation: Chiba Prefectural Institute of Public Health.
authors.forename: Takashi
authors.initials: T
authors.lastname: Hasegawa
authors.forename: Kazunaga
authors.initials: K
authors.lastname: Takahashi
authors.forename: Tomohide
authors.initials: T
authors.lastname: Fukiwake
authors.forename: Masaaki
authors.initials: M
authors.lastname: Saijo
authors.forename: Yuji
authors.initials: Y
authors.lastname: Motoki
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D019587:Dietary Supplements / Q000032:analysis*; D004295:Dihydroxyphenylalanine / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D005561:Formates; D007980:Levodopa; D013058:Mass Spectrometry / Q000379:methods*; D031299:Mucuna; D010936:Plant Extracts / Q000032:analysis*; D012996:Solutions; D021241:Spectrometry, Mass, Electrospray Ionization; D013237:Stereoisomerism; D014867:Water
chemical_list: D005561:Formates; D010936:Plant Extracts; D012996:Solutions; D014867:Water; C030544:formic acid; D007980:Levodopa; D004295:Dihydroxyphenylalanine