title: Certification of standard reference materials containing bitter orange.
abstract: A suite of three dietary supplement standard reference materials (SRMs) containing bitter orange has been developed, and the levels of five alkaloids and caffeine have been measured by multiple analytical methods. Synephrine, octopamine, tyramine, N-methyltyramine, hordenine, total alkaloids, and caffeine were determined by as many as six analytical methods, with measurements performed at the National Institute of Standards and Technology and at two collaborating laboratories. The methods offer substantial independence, with two types of extractions, two separation methods, and four detection methods. Excellent agreement was obtained among the measurements, with data reproducibility for most methods and analytes better than 5% relative standard deviation. The bitter-orange-containing dietary supplement SRMs are intended primarily for use as measurement controls and for use in the development and validation of analytical methods.
authors.affiliation: National Institute of Standards and Technology, Chemical Science and Technology Laboratory, 100 Bureau Drive, MS 8392, Gaithersburg, MD 20899-8392, USA. lane.sander@nist.gov
authors.forename: L C
authors.initials: LC
authors.lastname: Sander
authors.forename: K
authors.initials: K
authors.lastname: Putzbach
authors.forename: B C
authors.initials: BC
authors.lastname: Nelson
authors.forename: C A
authors.initials: CA
authors.lastname: Rimmer
authors.forename: M
authors.initials: M
authors.lastname: Bedner
authors.forename: J Brown
authors.initials: JB
authors.lastname: Thomas
authors.forename: B J
authors.initials: BJ
authors.lastname: Porter
authors.forename: L J
authors.initials: LJ
authors.lastname: Wood
authors.forename: M M
authors.initials: MM
authors.lastname: Schantz
authors.forename: K E
authors.initials: KE
authors.lastname: Murphy
authors.forename: K E
authors.initials: KE
authors.lastname: Sharpless
authors.forename: S A
authors.initials: SA
authors.lastname: Wise
authors.forename: J H
authors.initials: JH
authors.lastname: Yen
authors.forename: P H
authors.initials: PH
authors.lastname: Siitonen
authors.forename: R L
authors.initials: RL
authors.lastname: Evans
authors.forename: A
authors.initials: A
authors.lastname: Nguyen Pho
authors.forename: M C
authors.initials: MC
authors.lastname: Roman
authors.forename: J M
authors.initials: JM
authors.lastname: Betz
mesh_terms: D000470:Alkaloids; D002110:Caffeine; D002623:Chemistry Techniques, Analytical / Q000379:methods; D002957:Citrus / Q000737:chemistry* / Q000592:standards; D019587:Dietary Supplements / Q000032:analysis*; D012015:Reference Standards; D015203:Reproducibility of Results
chemical_list: D000470:Alkaloids; D002110:Caffeine