催化动力学光度法测定痕量锰

Catalytic kinetic photometric determination of trace amounts of manganese

在H2SO4介质中,在表面活性剂壬基酚聚氧乙烯（7）醚的活化下,Mn（Ⅱ）催化溴酸钾氧化甲基紫褪色,建立了动力学光度法测定痕量Mn（Ⅱ）的新方法.考查了最佳试验条件并进行了动力学参数的测定;该方法检出限为2.3×10^-7 g/L;线性范围0.0002～0.014 μg/mL;最大相对标准偏差为4.8%.用于水和面粉的测定,回收率在95.0%～104.7%之间;对面粉样用石墨炉原子吸收法进行了对比试验,方法相对误差低于±5.0%.

In a medium of sulfuric acid, a new catalytic kinetic photometry is proposed based on the oxidation discoloring of methyl violet by potassium bromate and activation of the NP- 7. The optimum conditions and kinetic parameters have been studied. It shows that the colored product has its maximum absorption at 576 nm; The detection limit of the catalytic photometry is 2.3 × 10^-7 g/L and the linear range is 0.01 - 0.70/.tg of manganese per 50 mL of solution. It has been used to determine trace amounts of manganese in water and flour with satisfactory results. The relative standard deviation is lower than 4.8% and the recoveries am 95.0% - 104.7% after adding standard solution into sampies; the results of flour am in agreement with values by GFAAS method with less than ± 5.0% relative error.