A New Spectrophotometric Determination of Traces of Arsenic with Silver Acetate in the Presence of Tween-80

A new simple and sensitive procedure for spectrophotometric determination of traces of arsenic has been developed. At pH 5.3, arsine generated usually reacts with silver acetate in the aqueous solution in the presence of Tween-80 to form yellow silver sol, which has an absorption maximum at 420 nm. The molar absorptivity at the wave is found to be 4.8 × 104 l·mole−1 · cm−1. Beer's law is obeyed for 0.3-5.0 μg of arsenic in 20 ml absorbing solution. This method has been used in the determination of arsenic in water and wastewater samples and results are found satisfactory.