Shanker R M, Nashed N E, Lindenbaum S
Department of Pharmaceutical Chemistry, University of Kansas, Lawrence 66045.
Pharm Res. 1992 Apr;9(4):485-91. doi: 10.1023/a:1015836228878.
A novel air-gap enzyme electrode was developed by amalgamating the principles controlling ion-selective electrodes, enzyme kinetics, and diffusion of molecules across membranes. Commercially available ammonia and carbon dioxide gas-sensing electrodes were modified to measure the respective gases over a head-space. A plexiglass cell was designed and fabricated to house the modified electrodes. The air-gap electrodes exhibited superior sensitivity and response characteristics compared to the original membrane electrodes. The plexiglass cell was divided into two compartments by virtue of a selectively permeable membrane. Enzymatic reactions were conducted in the cell to determine quantitatively the concentration of the substrate. L-Phenylalanine ammonia lyase was used to determine L-phenylalanine with the ammonia electrode and L-glutamate decarboxylase was utilized for the determination of L-glutamic acid by the carbon dioxide electrode. Near-Nernstian slopes were obtained for the response of the enzyme electrodes. In addition to the good reproducibility, the method provided unique ability to reuse the same enzyme solution for several determinations of various concentrations of the analyte. The performance of the two compartment cell and air-gap enzyme electrode was found to be superior in comparison to conventional enzyme electrodes.
通过融合控制离子选择性电极、酶动力学以及分子跨膜扩散的原理，开发了一种新型气隙酶电极。对市售的氨和二氧化碳气体传感电极进行了改进，以测量顶空上方的相应气体。设计并制造了一个有机玻璃池来容纳改进后的电极。与原始膜电极相比，气隙电极表现出卓越的灵敏度和响应特性。有机玻璃池借助选择性渗透膜被分为两个隔室。在池中进行酶促反应以定量测定底物浓度。使用L - 苯丙氨酸解氨酶通过氨电极测定L - 苯丙氨酸，利用L - 谷氨酸脱羧酶通过二氧化碳电极测定L - 谷氨酸。酶电极的响应获得了近能斯特斜率。除了良好的重现性外，该方法还具有独特的能力，即可以将相同的酶溶液重复用于多次测定不同浓度的分析物。与传统酶电极相比，发现双隔室池和气隙酶电极的性能更优。
