title: Determination of catechins and caffeine in proposed green tea standard reference materials by liquid chromatography-particle beam/electron ionization mass spectrometry (LC-PB/EIMS).
abstract: Presented here is the quantitative analysis of green tea NIST standard reference materials (SRMs) via liquid chromatography-particle beam/electron ionization mass spectrometry (LC-PB/EIMS). Three different NIST green tea standard reference materials (SRM 3254 Camellia sinesis Leaves, SRM 3255 C. sinesis Extract and SRM 3256 Green Tea-containing Oral Dosage Form) are characterized for the content of caffeine and a series of catechin species (gallic acid, catechin, epicatechin, epigallocatechin, epicatechin gallate and epigallocatechin gallate (EGCG)). The absolute limits of detection for caffeine and the catechin species were determined to be on the nanogram level. A reversed-phase chromatographic separation of the green tea reference materials was carried out on a commercial C(18) column using a gradient of water (containing 0.1% TFA) and 2:1 methanol:acetonitrile (containing 0.1%TFA) at 0.9mLmin(-1) and an analysis time of 50min. Quantification of caffeine and the catechin species was carried out using the standard addition and internal standard methods, with the latter providing appreciable improvements in precision and recovery.
authors.affiliation: Clemson University, Department of Chemistry, Biosystems Research Complex, 51 New Cherry Street, Clemson, SC 29634-1905, USA.
authors.forename: Joaudimir
authors.initials: J
authors.lastname: Castro
authors.forename: Tara
authors.initials: T
authors.lastname: Pregibon
authors.forename: Kristina
authors.initials: K
authors.lastname: Chumanov
authors.forename: R Kenneth
authors.initials: RK
authors.lastname: Marcus
mesh_terms: D002110:Caffeine / Q000032:analysis*; D028241:Camellia sinensis / Q000737:chemistry*; D002392:Catechin / Q000032:analysis*; D056148:Chromatography, Reverse-Phase / Q000379:methods; D005504:Food Analysis / Q000379:methods / Q000592:standards*; D018515:Plant Leaves / Q000737:chemistry; D012015:Reference Standards; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013662:Tea / Q000737:chemistry / Q000592:standards*
chemical_list: D013662:Tea; D002110:Caffeine; D002392:Catechin