The determination of trace antimony by flow injection catalytic spectrophotometry

A new flow-injection-inhibition discoloring spectrophotometric method using stopped-flow technique for determination of trace antimony(Ⅲ) is described.This method is based on the catalytic effect of antimony(Ⅲ) on the reaction of malachite green and hydrogen peroxide in the medium of Britton-Robinson buffer solution.The linear range of the determination is 0.01～2.0 μg/mL for antimony(Ⅲ) with a correlation coefficient of 0.9996,and the detection limit is 7.8×10-3 μg/mL with the sampling rate of 22.8 times per hour.The relative standard deviation of eleven replicate measurements is 0.97% for 0.1 μg/mL.The method has been applied to the determination of trace antimony(Ⅲ) in water samples with satisfactory results.The recoveries are 97.3%～97.7%.