Multivariate optimisation of the experimental conditions for determination of three methylxanthines by reversed-phase high-performance liquid chromatography.

摘要: Abstract Caffeine (1,3,7-trimethylxanthine), theobromine (3,7-dimethylxanthine) and theophylline (1,3-dimethylxanthine) are the most important naturally occurring methylxanthines. is a constituent of coffee other beverage included in many medicines. Theobromine formed as metabolites caffeine humans, also present tea, cocoa chocolate products. In order to improve chromatographic resolution (Rs) with good analysis time, experimental designs were applied for multivariate optimisation conditions an isocratic reversed-phase high-performance liquid (RP-HPLC) method used simultaneous determination caffeine, theophylline. The process was carried out two steps using full three-level factorial designs. factors optimised were: flow rate mobile phase composition. Optimal separation three methylxanthines obtained mixture water/ethanol/acetic acid (75:24:1%, v/v/v) 1.0 mL min−1. RP-HPLC/UV validated terms limit detection (LOD), quantitation (LOQ), linearity, recovery precision, calculated relative standard deviation (R.S.D.). these conditions, LOD 0.10 μg L−1 0.07 μg L−1 0.06 μg L−1 proposed fast, requires no extraction step or derivatization suitable quantification coffee, tea human urine samples.