Anodic stripping voltammetry using underpotential deposition allows sub 10 ppb measurement of Total As and As(III) in water

We report a sensitive stripping voltammetry method for the detection of total arsenic in aqueous solution using gold macroelectrodes based on the underpotential deposition (UPD) of As ad-atoms. The detection of As(III) or total arsenic can be selectively made by changing deposition potential, with detection of the total As content by deposition at high potential (- 1.3 V) and of As(III) by deposition at lower potential (- 0.9 V). Linear responses were found for both arsenic species in the range 0.01 μM–0.1 μM at gold macroelectrodes. The analytical useful signals were recorded at concentrations as low as 0.01 μM (0.8 μg L−1) for both arsenic species suggesting that this method can be used to detect total arsenic concentrations in drinking water within the threshold value of the WHO of 0.13 μM (10 μg L−1). The total arsenic (As(III)+As(V)) concentration can be measured by deposition at – 1.3 V on gold while the As(III) concentration can be measured by deposition at – 0.9 V. The As(V) concentration then can be determined by subtraction from the total arsenic concentration of the As(III) concentration. [Display omitted] •Anodic stripping voltammetry using underpotential deposition.•Sub 10 ppb measurement of As in water.•Total As detection and As(III) vs AS(V) speciation.