El-Kosasy Amira M, Shehata Mostafa A, Hassan Nagiba Y, Fayed Ahmad S, El-Zeany Badr A
Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt.
Talanta. 2005 Apr 30;66(3):746-54. doi: 10.1016/j.talanta.2004.12.027. Epub 2005 Jan 18.
Four glutathione (GSH)-selective electrodes were developed with different techniques and in different polymeric matrices. Precipitation-based technique with bathophenanthroline-ferrous as cationic exchanger in polyvinyl chloride (PVC) matrix was used for sensor 1 fabrication. beta-Cyclodextrin (beta-CD)-based technique with either tetrakis(4-chlorophenyl)borate (TpClPB) or bathophenanthroline-ferrous as fixed anionic and cationic sites in PVC matrix was used for fabrication of sensors 2 and 3, respectively. beta-CD-based technique with TpClPB as fixed anionic site in polyurethane (Tecoflex) matrix was used for sensor 4 fabrication. Linear responses of 1x10(-5) to 1x10(-4)M and 1x10(-6) to 1x10(-3)M with slopes of 37.5 and 32.0mV/decade within pH 7-8 were obtained by using electrodes 1 and 3, respectively. On the other hand, linear responses of 1x10(-5) to 1x10(-2) and 1x10(-5) to 1x10(-3)M with slopes of 47.9 and 54.3mV/decade within pH 5-6 were obtained by using electrodes 2 and 4, respectively. The percentage recoveries for determination of GSH by the four proposed GSH-selective electrodes were 100+/-1, 100.5+/-0.7, 100+/-1 and 99.0+/-0.8% for sensors 1, 2, 3 and 4, respectively. Determination of GSH in capsules by the proposed electrodes revealed their applicability for determination of GSH in its pharmaceutical formulations. Also, they were used to determine GSH selectively in presence of its oxidized form (GSSG). Sensor 4 was successfully applied for determination of glutathione in plasma with average recovery of 100.4+/-1.11%. The proposed method was compared with a reported one. No significant difference for both accuracy and precision was observed.
采用不同技术和不同聚合物基质制备了四种谷胱甘肽（GSH）选择性电极。传感器1的制备采用沉淀法，以邻二氮菲亚铁作为阳离子交换剂，聚氯乙烯（PVC）为基质。传感器2和3的制备分别采用基于β-环糊精（β-CD）的技术，以四（4-氯苯基）硼酸（TpClPB）或邻二氮菲亚铁作为PVC基质中的固定阴离子和阳离子位点。传感器4的制备采用基于β-环糊精的技术，以TpClPB作为聚氨酯（Tecoflex）基质中的固定阴离子位点。电极1和3分别在pH 7 - 8范围内获得了1×10⁻⁵至1×10⁻⁴M和1×10⁻⁶至1×10⁻³M的线性响应，斜率分别为37.5和32.0mV/十倍浓度变化。另一方面，电极2和4分别在pH 5 - 6范围内获得了1×10⁻⁵至1×10⁻²和1×10⁻⁵至1×10⁻³M的线性响应，斜率分别为47.9和54.3mV/十倍浓度变化。所提出的四种GSH选择性电极测定GSH的回收率分别为：传感器1为100±1%，传感器2为100.5±0.7%，传感器3为100±1%，传感器4为99.0±0.8%。所提出的电极用于测定胶囊中的GSH，表明它们适用于测定其药物制剂中的GSH。此外，它们还用于在其氧化形式（GSSG）存在下选择性测定GSH。传感器4成功应用于血浆中谷胱甘肽的测定，平均回收率为100.4±1.11%。将所提出的方法与已报道的方法进行了比较。在准确度和精密度方面均未观察到显著差异。
