title: Capillary liquid chromatography combined with pressurized liquid extraction and dispersive liquid-liquid microextraction for the determination of vitamin E in cosmetic products.
abstract: Capillary liquid chromatography (LC) is used for the determination of tocopherols and tocotrienols in cosmetic products. Dispersive liquid-liquid microextraction (DLLME) allows the analytes to be preconcentrated into a very small volume of organic solvent which is then injected into the chromatograph running at a very low flow rate. Pressurized liquid extraction (PLE) at a high temperature and pressure was used to isolate vitamin E forms from cosmetics. The Taguchi experimental method was used to optimize the factors affecting DLLME. The parameters selected were 2mL of acetonitrile (disperser solvent), 100μL carbon tetrachloride (extraction solvent) and 10mL aqueous solution. A volume of 5μL of the organic phase was injected into the reversed-phase capillary LC system equipped with a diode array detector and using an isocratic mobile phase composed of an 95:5 (v/v) methanol:water mixture at a flow-rate of 20μLmin(-1). Quantification was carried out using aqueous standards and detection limits were in the range 0.1-0.5ngmL(-1), corresponding to 3-15ngg(-1) in the cosmetic sample. The recoveries were in the 87-105% range, with RSDs lower than 7.8%. The method was validated according to international guidelines and using a certified reference material.
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, E-30100 Murcia, Spain. Electronic address: pilarvi@um.es.
authors.forename: Pilar
authors.initials: P
authors.lastname: Viñas
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, E-30100 Murcia, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Pastor-Belda
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, E-30100 Murcia, Spain.
authors.forename: Natalia
authors.initials: N
authors.lastname: Campillo
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, E-30100 Murcia, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Bravo-Bravo
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, E-30100 Murcia, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Hernández-Córdoba
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D002251:Carbon Tetrachloride / Q000737:chemistry; D002853:Chromatography, Liquid / Q000379:methods; D003358:Cosmetics / Q000032:analysis* / Q000737:chemistry*; D057230:Limit of Detection; D059627:Liquid Phase Microextraction / Q000379:methods; D000432:Methanol / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D014810:Vitamin E / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D003358:Cosmetics; D012996:Solutions; D014867:Water; D014810:Vitamin E; D002251:Carbon Tetrachloride; D000432:Methanol; C032159:acetonitrile
keywords: Capillary liquid chromatography; Cosmetics; Dispersive liquid–liquid microextraction; Pressurized liquid extraction; Tocopherols