Jin W, Yu D, Dong Q, Ye X
Laboratory of Analytical Science, School of Chemistry, Shandong University, China.
J Chromatogr Sci. 2000 Jan;38(1):11-5. doi: 10.1093/chromsci/38.1.11.
Capillary zone electrophoresis is employed for the determination of caffeine using end-column amperometric detection with a carbon fiber microdisk array electrode at a constant potential of 1.45 V versus a saturated calomel electrode. The optimum conditions of separation and detection are 0.1 52mM NaH2PO4-0.648mM Na2HPO4 for the buffer solution, 20 kV for the separation voltage, 5 kV for the injection voltage, and 10s for the injection time. The limit of detection is 2.9 x 10(-4)mM or 1.2 fmol (signal-to-noise ratio = 2). The relative standard deviation is 0.68% for the migration time and 2.3% for the electrophoretic peak current. The method is applied to determining caffeine in human serum and a cola drink.
采用毛细管区带电泳法，以碳纤维微盘阵列电极作为柱端安培检测器，在相对于饱和甘汞电极1.45 V的恒定电位下测定咖啡因。分离和检测的最佳条件为：缓冲溶液为0.1 52 mM磷酸二氢钠-0.648 mM磷酸氢二钠，分离电压为20 kV，进样电压为5 kV，进样时间为10 s。检测限为2.9×10(-4) mM或1.2 fmol（信噪比=2）。迁移时间的相对标准偏差为0.68%，电泳峰电流的相对标准偏差为2.3%。该方法用于测定人血清和可乐饮料中的咖啡因。
