Rapid Determination of Molybdenum in Wastewater Using Flow Injection Spectrophotometry

A mixture chromogenic reagent was prepared,which was consisted of potassium thiocyanate,thiourea and cupper sulfate with different concentrations and proportions.The reagent could react with molybdenum(VI) quickly to form a stable orange-red colored complex in an acidic medium,which enabled the quantitative measurement of molybdenum using a spectrophotometer at 460 nm.Flow injection analysis technique was used to exploit the reaction for the rapid,reproducible and accurate determination of molybdenum in wastewater samples.The calibration curve was linear over a range from 1 to 20 mg L-1 with a detection limit of 0.05 mg L-1.The relative standard deviation was less than 3% for the determination of 10 mg L-1 molybdenum(n=11) and a sampling frequency of 60 h-1 was achieved.The proposed method was applied successfully for the determination of molybdenum in industrial wastewater samples with satisfactory results.