Screen-Printed Amperometric Acetylcholinesterase Electrode For The Determinations Of Nerve Agents: Sarin And Soman

Disposable amperometric acetylcholinesterase electrodes, which were fabricated by screen-printing technique and with a method. of immobilization of enzyme by exposure; to glutaraldehyde vapoure, were used for the determinations of nerve agents sarin and soman. Using acetylthiocholine as the substrate, the sensors showed maximum sensitivity at pH 7.2 and 37 degrees C. The kinetic constants, K-m and I-max, were 3.5 mol/L and 2.5 mu A, respectively. The activity of the sensors was inhibited by sarin and soman. Incubating the sensors for 2 min, calibration plots of the percentage inhibition versus the logarithms of sarin and soman concentrations were found ta be linear over the range 5 similar to 400 mu g/L, and 5 similar to 100 mu g/L, respectively. The recoveries for the determinations of sarin and soman in lake water samples were 127.4% and 125.0%, respectively, with RSD 14.9% and 13.6%, respectively.