title: A systematic approach to quantitation of ephedra alkaloids in natural health products.
abstract: A method for accurate determination of ephedrine (E) alkaloids in natural health products (NHP) is described. The NIST dietary supplement standard reference materials (SRMs) were selected for these studies. These SRMs comprise ground Ma Huang herb (Ephedra sinica Stapf.), a spray dried extract of the former, and commercial formulations derived from gel caps and a protein drink. The efficiency of sonication-assisted extraction and Soxhlet extraction was studied using both ammonium formate and potassium phosphate in 3% methanol as extraction media. The efficiency of SPE clean-up of the extract deteriorated rapidly when increasing amounts of sample matrix or analyte were processed, because of limited cartridge capacity. Quantitation by the method of additions was required to ensure the highest accuracy using both LC-UV and ES-LC-MS-MS techniques. Whereas the LC-UV method is more convenient and precise, the results are more questionable than ES-LC-MS-MS, because species-specific detection is not possible.
authors.affiliation: National Research Council Canada, Institute for National Measurement Standards, Ottawa, ON, Canada, K1A 0R6. joe.lam@nrc.ca
authors.forename: Joseph W H
authors.initials: JW
authors.lastname: Lam
authors.forename: Graeme J
authors.initials: GJ
authors.lastname: Gardner
authors.forename: Margaret
authors.initials: M
authors.lastname: McCooeye
authors.forename: Catharine A
authors.initials: CA
authors.lastname: Fraser
authors.forename: Ralph E
authors.initials: RE
authors.lastname: Sturgeon
mesh_terms: D000470:Alkaloids / Q000032:analysis*; D001688:Biological Products / Q000737:chemistry*; D019587:Dietary Supplements / Q000032:analysis*; D004365:Drugs, Chinese Herbal; D029789:Ephedra / Q000737:chemistry*; D029790:Ephedra sinica; D005561:Formates / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods; D000432:Methanol / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry; D010936:Plant Extracts / Q000494:pharmacology; D028321:Plant Preparations; D017680:Potassium Compounds / Q000737:chemistry; D012997:Solvents / Q000737:chemistry*; D013997:Time Factors
chemical_list: D000470:Alkaloids; D001688:Biological Products; D004365:Drugs, Chinese Herbal; D005561:Formates; D010710:Phosphates; D010936:Plant Extracts; D028321:Plant Preparations; D017680:Potassium Compounds; D012997:Solvents; C030544:formic acid; C099950:Ephedrae herba; C013216:potassium phosphate; D000432:Methanol