痕量锰的动力学分光光度法测定(N,N-二甲基苯胺-NaIO_4体系)

Catalytic Kinetic Spectrophotometric Determination of Trace Mn(Ⅱ) (N,N-Dimethylaniline-Periodate System)

基于痕量锰对某些氧化还原反应的催化作用,已建立了一系列测定锰的催化动力学分光光度法。常用的氧化剂是过氧化氢或高碘酸盐,还原剂则以芳香胺类较为多见,如孔雀绿和N,N-二乙基苯胺等,但至今未见用N,N-二甲基苯胺作为还原剂的报道。我们发现,在pH为7.6的Clark-Lubs缓冲体系中,Mn(Ⅱ)能灵敏地催化高碘酸钠氧化N,N-二甲基苯胺的显色反应。

A high sensitive method for determining trace Mn(Ⅱ ) was set up by a new indicating reaction in which periodate oxidizes N ,N-dimethylaniline to colour with Mn( Ⅱ ) as a catalyst-After a fixed reaction time, the amount of oxidation product is direct proportional to the concentration of Mn( Ⅱ ). The optimum conditions are temperature 55Ⅱ and pH 7. 6. The limit of detection for Mn (Ⅱ ) is 0, 2 ng Mn( Ⅱ)/ml. The linear range of determination is 0. 2 to 8. 0 ng Mn( Ⅱ )/ml. The method was used in sea water, nails and hair with satisfactory results.