咖啡因离子选择性电极的研制及其用于测定可乐饮料中咖啡因

Preparation of Caffeine-Ion Selective Electrode and Its Application to Determination of Caffeine in Coke Drink

摘要: 研制了以咖啡因-磷钼酸缔合物为电活性物质的离子选择性电极。试验表明:该离子选择性电极对咖啡因具有良好的选择性和电位响应特性。在pH 2.54磷酸盐缓冲溶液中,电极电位呈现能斯特响应,线性范围为5.0×10-6~1.0×10-2mol·L-1,斜率为51.4 mV·pc-1。将该电极用于测定可乐饮料中咖啡因的含量,测得方法的回收率在98.4%~102.4%之间。

Abstract: An ion selective electrode (ISE) using the association complex of caffeine with molybdophosphoric acid as electroactive substance was prepared. It was found that this ISE behaved with excellent selectivity and characteristic potential response toward caffeine. Nernst potential response was obtained in the range of 5×10-6-1.0×10-2mol·L-1 with slop of 51.4 mV·pc-1 in PBS of pH 2.54. Recovery was tested by standard addition method using samples of coke drink as matrixes, values of recovery found were in the range of 98.4%-102.4%.