Electrochemical aptamer biosensor for As³⁺based on apta deep trapped Ag-Au alloy nanoparticles-impregnated glassy carbon electrode

Abstract

Arsenic is toxic, so being able to detect and monitor arsenic in aqueous environments is important. Here, we report a biosensor for As3+ (Arsenic (III)) which uses a glassy carbon electrode modified with Ag-Au alloy NPs (i.e. Silver and gold alloy nanoparticles) and loaded with an aptamer. The electrode contains apta deep trapped Ag-Au alloy NPs, and the detection method employs cyclic voltammetry and differential pulse voltammetry. Captured As3+ ions undergo electrochemical reaction, producing a significant increase in the current which is observed in the voltammetry curves. This current increase is a result of the electrocatalytic properties of the NPs. The electrode is used for the determination of As3+ in real water samples. The activity curve is linear for As3+ concentrations of 0.01µg/L to 10 µg/L, and the detection limit is 0.003 × 10−3µg/L. The operation of the biosensor is reproducible, stable, and selective, and the biosensor performs well in determining As3+ in water from natural water courses, lakes, and wells.