Mulchandani P, Mulchandani A, Kaneva I, Chen W
Department of Chemical and Environmental Engineering, University of California, Riverside 92521, USA.
Biosens Bioelectron. 1999 Jan 1;14(1):77-85. doi: 10.1016/s0956-5663(98)00096-7.
A potentiometric enzyme electrode for the direct measurement of organophosphate (OP) nerve agents was developed. The basic element of this enzyme electrode was a pH electrode modified with an immobilized organophosphorus hydrolase (OPH) layer formed by cross-linking OPH with bovine serum albumin (BSA) and glutaradehyde. OPH catalyses the hydrolysis of organophosphorus pesticides to release protons, the concentration of which is proportional to the amount of hydrolysed substrate. The sensor signal and response time was optimized with respect to the buffer pH, ionic concentration of buffer, temperature, and units of OPH immobilized using paraoxon as substrate. The best sensitivity and response time were obtained using a sensor constructed with 500 IU of OPH and operating in pH 8.5, 1 mM HEPES buffer. Using these conditions, the biosensor was used to measure as low as 2 microM of paraoxon, ethyl parathion, methyl parathion and diazinon. The biosensor was completely stable for at least one month when stored in pH 8.5, 1 mM HEPES + 100 mM NaCl buffer at 4 degrees C.
开发了一种用于直接测定有机磷酸酯（OP）神经毒剂的电位型酶电极。该酶电极的基本元件是一个pH电极，其用通过将有机磷水解酶（OPH）与牛血清白蛋白（BSA）和戊二醛交联形成的固定化OPH层进行了修饰。OPH催化有机磷农药的水解以释放质子，质子的浓度与水解底物的量成正比。针对缓冲液pH、缓冲液离子浓度、温度以及使用对氧磷作为底物固定的OPH单位，对传感器信号和响应时间进行了优化。使用由500 IU的OPH构建并在pH 8.5、1 mM HEPES缓冲液中运行的传感器获得了最佳灵敏度和响应时间。在这些条件下，该生物传感器用于测量低至2 microM的对氧磷、乙基对硫磷、甲基对硫磷和二嗪农。当在4℃下储存在pH 8.5、1 mM HEPES + 100 mM NaCl缓冲液中时，该生物传感器至少一个月完全稳定。
