Stefan R I, Van Staden J K, Aboul-Enein H Y
Department of Chemistry, University of Pretoria, Pretoria 0002, South Africa.
Chirality. 1999;11(8):631-4. doi: 10.1002/(SICI)1520-636X(1999)11:8<631::AID-CHIR4>3.0.CO;2-K.
A potentiometric, enantioselective membrane electrode based on graphite paste (graphite powder and paraffin oil) has been constructed. The graphite paste is impregnated with a 10(-3) mol/L 2-hydroxy-3-trimethylammoniopropyl-beta-cyclodextrin (as chloride salt) solution. The potentiometric, enantioselective membrane electrode can be used reliably for enantiopurity tests of S-perindopril using a chronopotentiometric (zero current) technique, in the 10(-5)-10(-2) mol/L concentration range (detection limit 5 x 10(-6) mol/L), with an average recovery of 99.58% (RSD = 0.33%). The enantioselectivity was determined over R-perindopril and D-proline. The response characteristics of the enantioselective, potentiometric membrane electrode were also determined for R-perindopril. It was shown that L-proline is the main interfering compound. The surface of the electrode can be regenerated simply by polishing, obtaining a fresh surface ready to be used in a new assay.
已构建了一种基于石墨糊（石墨粉和石蜡油）的电位型对映体选择性膜电极。石墨糊用10⁻³ mol/L的2-羟基-3-三甲基铵基丙基-β-环糊精（作为氯盐）溶液浸渍。该电位型对映体选择性膜电极可使用计时电位法（零电流）技术可靠地用于S-培哚普利的对映体纯度测试，浓度范围为10⁻⁵ - 10⁻² mol/L（检测限为5×10⁻⁶ mol/L），平均回收率为99.58%（相对标准偏差 = 0.33%）。测定了该对映体选择性膜电极对R-培哚普利和D-脯氨酸的对映选择性。还测定了该对映体选择性电位型膜电极对R-培哚普利的响应特性。结果表明，L-脯氨酸是主要的干扰化合物。电极表面只需通过抛光即可再生，从而获得可用于新分析的新鲜表面。
