A simple catalytic kinetic spectrophotometric method for the determination of osmium in wastewater samples

This paper reports a new simple, sensitive and selective catalytic kinetic spectrophotometric method for the determination of trace quantities of Os(VIII). Janus Green is oxidized by hydrogen peroxide in borate buffer at pH 9.0 and Os(VIII) catalyzes the reaction. Reaction rate was monitored spectrophotometrically at 618 nm. The calibration graph is linear for 0.4 – 430.0 ng mL-1 of Os(VIII) and the detection limit is 0.08 ng mL-1 of Os(VIII). The relative standard deviations (n = 10) varied from 2.75 to 1.32% for 40.0 and 400.0 ng mL-1 of Os(VIII), respectively. The effect of presence of foreign ions was also investigated. The proposed method was applied in real samples with satisfactory results.