title: Analysis of synthetic chemical drugs in adulterated Chinese medicines by capillary electrophoresis/electrospray ionization mass spectrometry.
abstract: Sixteen synthetic chemical drugs, often found in adulterated Chinese medicines, were studied by capillary electrophoresis/UV absorbance (CE/UV) and capillary electrophoresis/electrospray ionization mass spectrometry (CE/ESI-MS). Only nine peaks were detected with CZE/UV, but on-line CZE/MS provided clear identification for most compounds. For a real sample of a Chinese medicinal preparation, a few adulterants were identified by their migration times and protonated molecular ions. For coeluting compounds, more reliable identification was achieved by MS/MS in selected reaction monitoring mode. Micellar electrokinetic chromatography (MEKC) using sodium dodecyl sulfate (SDS) provided better separation than capillary zone electrophoresis (CZE), and, under optimal conditions, fourteen peaks were detected using UV detection. In ESI, the interference of SDS was less severe in positive ion mode than in negative ion mode. Up to 20 mM SDS could be used in direct coupling of MEKC with ESI-MS if the mass spectrometer was operated in positive ion mode. Because of better resolution in MEKC, adulterants can be identified without the use of MS/MS.
authors.affiliation: Department of Chemistry, National Taiwan University, Taipei, Taiwan, R.O.C.
authors.forename: H L
authors.initials: HL
authors.lastname: Cheng
authors.forename: M C
authors.initials: MC
authors.lastname: Tseng
authors.forename: P L
authors.initials: PL
authors.lastname: Tsai
authors.forename: G R
authors.initials: GR
authors.lastname: Her
mesh_terms: D000893:Anti-Inflammatory Agents / Q000032:analysis* / Q000737:chemistry; D002110:Caffeine / Q000032:analysis / Q000737:chemistry; D003975:Diazepam / Q000032:analysis / Q000737:chemistry; D004340:Drug Contamination; D004365:Drugs, Chinese Herbal / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000379:methods; D008823:Micelles; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013056:Spectrophotometry, Ultraviolet; D013624:Taiwan
chemical_list: D000893:Anti-Inflammatory Agents; D004365:Drugs, Chinese Herbal; D008823:Micelles; D002110:Caffeine; D003975:Diazepam