Application of Gold Nanoparticles with 1,6-Hexanedithiol Modified Screen-Printed Carbon Electrode As a Sensor for Determination of Arsenic in Environmental Samples

Abstract

The development of electrochemical nano sensor was described for the detection of total arsenic in groundwater, soil, food and honey samples based on the formation of gold nanoparticles. Screen printed carbon electrodes were modified with gold nanoparticles and linked with 1,6-hexanedithiol self-assembled monolayers. The electrodeposition of Au nanoparticles was applied in 10 mL of the solution that totally cover the screen-printed carbon electrode while applying a constant potential of -0.4 V (vs Ag within SPCE) for 600 sec. Cyclic voltammetry was used to characterize the gold nanoparticles before and after modified with 1,6-hexanedithiol self-assembled monolayers on screen printed carbon electrode (Figure 1). Square wave anodic stripping voltammetry with multi point standard addition method was examined for the detection of As(III) and As(V) on Au NPs-1,6-hexanedithiol modified screen printed carbon electrode under optimized conditions. As(III) and As(V) was firstly, deposited for 60 seconds by the reduction of arsenic in buffer solution: (citric acid, sodium chloride and ascorbic acid pH 2.0), followed by As stripping between -0.20 and 0.35 V at the following parameters: scan rate: 100 mV s-1, frequency: 60 Hz, amplitude: 0.025 V and increment: 5.0 mV. it was found that Au- NPs with 1,6-hexanedithiol modified screen-printed carbon electrode had a highest anodic stripping peak current at 0.201V. The limit of detection value for arsenic was identified to be 1.7 ng ml-1. Also, the electrochemical nanosensor showed excellent reproducibility and high stability. The developed method was successfully applied to detect total arsenic in ground water, soil and wastewater samples. Figure 1