Dual wave β-correction spectrophotometry for trace determination and chemical speciation of As(III)/As(V) in water

•Simple strategy for trace level determination of As(III) in water samples.•Very good LOD (10 ng/mL) and LDR (0.1–4.5 μg/mL) was achieved.•Robust method with minimal interference from surfactants, salinity and diverse ions.•Easily employed for speciation and total arsenic determination in water samples.