Catalytic kinetic speetrophotometric determination of trace manganese(II) with Tween-80 as enhanced sensitivity agent

A new method has been developed for the determination of trace manganese by catalytic ki- netic spectrophotometry.The method is based on the catalyzing effect of manganese(Ⅱ)on oxidation of arsenazoⅢby potassium periodate in HAc-NaAc medium and in the presence of Tween-80 as an en- hanced agent and 1,10-phenanthroline as an activator.The kinetic parameters have been determined. The sensitivity enhenced by 1.88 times in the presence of Tween-80 than in the absence of Tween-80. The calibration curve was linear over the range 0.06—2.4μg/L for manganese(Ⅱ)at 540nm.The rela- tive standard deviation is 1.4% for eleven determination of 2μg/L manganese(Ⅱ).The detection limit was 4.4×10~(-8)g/L.The method has been applied to the determination of manganese(Ⅱ)in drinking wa- ter and river water with satisfactory results.