Spectrophotometric Method for Rapid Determination of As(V) and As(III) in Industrial Wastewater

• • Achieves As(V) quantification in <10 min and total As (and As(III) by difference) in <15 min, enabling real-time process control and emergency response in industrial settings. • • Optimal conditions: H+ = 1 mol·L−1, Na2S = 5 mmol·L−1, reaction 3 min, N2 purge 2 min; for total As: NaClO = 10 mmol·L−1, oxidation 5 min at pH 12. These parameters ensure complete reaction and removal of H2S interference. • • Linear range 0.5–50 mg·L−1 (R² = 0.999), detection limit 0.17 mg·L−1, spike recoveries 101.9%–104.1%, RSD 1.06%, demonstrating high accuracy and precision for industrial wastewater matrices. • • Field validation against HPLC-ICP-MS and IC-HG-AFS on real mining wastewater showed relative deviations <10%, confirming reliability while cutting instrument cost and operational complexity dramatically.