Zhao Y, Lunte C E
Department of Chemistry, University of Kansas, Lawrence 66045, USA.
J Chromatogr B Biomed Sci Appl. 1997 Jan 24;688(2):265-74. doi: 10.1016/s0378-4347(96)00278-2.
The determination of caffeine and its analogues is important for a wide variety of analyses and is performed in an assortment of matrices ranging from food to clinical samples. While reversed-phase HPLC has become the standard analysis protocol in most laboratories, capillary electrophoresis has the advantages of higher separation efficiency and shorter separation time. The micellar capillary electrophoresis (MECC) separation of caffeine and its metabolites, theobromine, paraxanthine, theophylline and 1,3,7-trimethyluric acid was investigated using sodium dodecyl sulphate (SDS) as the micellar phase. The effects of pH, micelle concentration, buffer concentration, ionic strength, buffer salts, applied voltage and injection time were studied to select the optimum conditions for the determination of caffeine and its four analogues in drugs, foods and body fluids. Caffeine and its three analogues were resolved within 120 s with detection limits less than 1 microgram/ml. Samples could be analyzed utilizing direct injection with satisfactory resolution and reproducibility.
咖啡因及其类似物的测定对于多种分析而言都很重要，并且在从食品到临床样本等各种各样的基质中进行。虽然反相高效液相色谱法已成为大多数实验室的标准分析方法，但毛细管电泳具有分离效率更高和分离时间更短的优点。使用十二烷基硫酸钠（SDS）作为胶束相，研究了咖啡因及其代谢物可可碱、副黄嘌呤、茶碱和1,3,7-三甲基尿酸的胶束毛细管电泳（MECC）分离。研究了pH值、胶束浓度、缓冲液浓度、离子强度、缓冲盐、施加电压和进样时间的影响，以选择在药物、食品和体液中测定咖啡因及其四种类似物的最佳条件。咖啡因及其三种类似物在120秒内实现分离，检测限低于1微克/毫升。采用直接进样即可对样品进行分析，分离度和重现性良好。
