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Multivariate optimisation of the experimental conditions for determination of three methylxanthines by reversed-phase high-performance liquid chromatography.
MedLine Citation:
PMID:  18970272     Owner:  NLM     Status:  In-Data-Review    
Abstract/OtherAbstract:
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 (R(s)) 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 1.0mLmin(-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 0.10mugL(-1) for caffeine, 0.07mugL(-1) for theobromine and 0.06mugL(-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.
Authors:
Nádia M de Aragão; Márcia C C Veloso; Márcia Souza Bispo; Sérgio L C Ferreira; Jailson B de Andrade
Publication Detail:
Type:  Journal Article     Date:  2005-06-22
Journal Detail:
Title:  Talanta     Volume:  67     ISSN:  1873-3573     ISO Abbreviation:  Talanta     Publication Date:  2005 Oct 
Date Detail:
Created Date:  2008-10-30     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  2984816R     Medline TA:  Talanta     Country:  England    
Other Details:
Languages:  eng     Pagination:  1007-13     Citation Subset:  -    
Affiliation:
Universidade Estadual do Sudoeste da Bahia - UESB, 45.200-000 Jequié Bahia, Brazil.
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