A electrochemical biosensor for As(III) determination has been developed by immobilization of the Alcaligenis faecalis bacteria on gold nanoparticle–modified screen–printed carbon electrode (AuNPs–SPCE). The detection of As(III) is due to the catalytic activity of arsenite oxidase enzyme which oxidizes As(III) to As(V) producing an analytical signal. To enhance the performance of the biosensor, was optimized the amount of bacteria, amount of glutaraldehyde and incubation time applied in the preparation of the electrode, in addition to the effect of pH and applied potential. The analytical application was carried out applying 300 mV (pH = 7) obtaining a LOD of 6.61 μmol L⁻¹ (R = 0.9975) and 700 mV (pH = 12) obtaining a LOD of 1.84 μmol L⁻¹ (R = 0.9983). AF/AuNPs–SPCE was applied to the determination of total arsenic in Loa river water samples after reduction, with satisfactory results.

通过将粪便粪便细菌固定在金纳米粒子修饰的丝网印刷碳电极（AuNPs-SPCE）上，开发了一种用于测定As（III）的电化学生物传感器。As（III）的检测归因于亚砷酸氧化酶的催化活性，该酶将As（III）氧化为As（V），产生分析信号。为了提高生物传感器的性能，除了pH和施加电势的影响外，还优化了电极制备中的细菌数量，戊二醛数量和孵育时间。通过施加300 mV（pH = 7）获得LOD为6.61μmolL ^-1（R = 0.9975）和700 mV（pH = 12）获得LOD为1.84μmolL ^-1（R = 0.9983）进行分析应用。AF / AuNPs-SPCE用于还原后Loa河水样中总砷的测定。