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Please use this identifier to cite or link to this item: http://repositorio.ufba.br/ri/handle/ri/13541

Title: Multivariate optimisation of the experimental conditions for determination of three methylxanthines by reversed-phase high-performance liquid chromatography
Other Titles: Talanta
Authors: Bispo, Márcia Sousa
Ferreira, Sergio Luis Costa
Andrade, Jailson Bittencourt de
Aragão, Nádia Machado de
Veloso, Márcia Cristina da Cunha
Keywords: Methylxanthines;Multivariate optimisation;Isocratic elution;RP-HPLC/UV
Issue Date: 2005
Abstract: Caffeine (1,3,7-trimethylxanthine), theobromine (3,7-dimethylxanthine) and theophylline (1,3-dimethylxanthine) are the most important naturally occurring methylxanthines. Caffeine is a constituent of coffee and other beverage and included in many medicines. Theobromine and theophylline are formed as metabolites of caffeine in humans, and are also present in tea, cocoa and chocolate products. In order to improve the chromatographic resolution (Rs) with a good analysis time, experimental designs were applied for multivariate optimisation of the experimental conditions of an isocratic reversed-phase high-performance liquid chromatographic (RP-HPLC) method used for the simultaneous determination of caffeine, theobromine and theophylline. The optimisation process was carried out in two steps using full three-level factorial designs. The factors optimised were: flow rate and mobile phase composition. Optimal conditions for the separation of the three methylxanthines were obtained using a mixture of water/ethanol/acetic acid (75:24:1%, v/v/v) as mobile phase and a flow rate of 1.0 mL min−1. The RP-HPLC/UV method was validated in terms of limit of detection (LOD), limit of quantitation (LOQ), linearity, recovery and the precision, calculated as relative standard deviation (R.S.D.). In these conditions, the LOD was 0.10 μg L−1 for caffeine, 0.07 μg L−1 for theobromine and 0.06 μg L−1 for theophylline. The proposed method is fast, requires no extraction step or derivatization and was suitable for quantification of these methylxanthines in coffee, tea and human urine samples.
Description: Texto completo: acesso restrito. p.1007–1013
URI: http://repositorio.ufba.br/ri/handle/ri/13541
ISSN: 0039-9140
Appears in Collections:Artigos Publicados em Periódicos (Quimica)

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