title: Improved sample pre-treatment for determination of caffeine in tea using a cartridge filled with polyvinylpolypyrroridone (PVPP).
abstract: We have improved sample pre-treatment for the effective removal of polyphenols and simple analysis of caffeine in tea using a cartridge filled with polyvinylpolypyrroridone (PVPP). Nearly 100% of catechins were removed from the green tea sample and caffeine was completely recovered in the range of 98.2-101.3% by sample pre-treatment with a PVPP cartridge. Reproducibility of preparing PVPP pre-treatment cartridges was sufficient for quantitative analysis, because RSDs of analytical values for caffeine obtained by using three individual pre-treatment cartridges filled with 10-200 mg PVPP were 0.60-2.8%. The PVPP pre-treatment cartridge also removed polyphenols perfectly and recovered caffeine faultlessly from oolong and black tea samples. Comparison with the conventional method without sample pre-treatment indicated that the present pre-treatment method with a PVPP cartridge was useful for the simple and precise analysis of caffeine in green, oolong and black tea samples.
authors.affiliation: Faculty of Pharmaceutical Sciences, Doshisha Women's University, Kyoto, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Yamauchi
authors.forename: Akiko
authors.initials: A
authors.lastname: Nakamura
authors.forename: Miki
authors.initials: M
authors.lastname: Kitai
authors.forename: Kirara
authors.initials: K
authors.lastname: Hatanaka
authors.forename: Iho
authors.initials: I
authors.lastname: Kohno
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Tanimoto
mesh_terms: D002110:Caffeine / Q000032:analysis*; D002392:Catechin / Q000032:analysis; D000697:Central Nervous System Stimulants / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D011205:Povidone / Q000031:analogs & derivatives* / Q000032:analysis; D013662:Tea / Q000737:chemistry*