铁(Ⅱ)-亚硝基R盐-双氧水体系极谱波研究及应用

Polarographic Behavior of Iron (Ⅱ)-Nitroso-R Salt-Hydrogen Peroxide System and the Determination of Iron

在ｐＨ５．５ ＨＡｃ－ＮａＡｃ缓冲溶液中，以硫酸肼还原 Ｆｅ（Ⅲ）成 Ｆｅ（Ⅱ），Ｆｅ２＋与亚硝基 Ｒ盐生成络合物，在Ｈ２Ｏ２在下可于－０．３５ Ｖ（ｖｓ．ＣＥ）处产生一个灵敏的极谱波，二阶导数波高与铁浓度在０．５～２００μｇ／Ｌ范围内呈线性关系，检出限０．３μｇ／Ｌ。研究了极谱波性质和机理。该波为一带吸附性质的平行催化波，络合物中配位体亚硝基Ｒ盐在电极上还原，还原的中间产物被Ｈ２Ｏ２氧化成原来的状态。本法灵敏、操作简单，已用于水样中痕量铁的直接测定。

In pH 5.5 acetate buffer solution, a complex of ferrous ion and nitroso-R salt was formed. In the presence of 3 .0% hydrogen peroxide, a sensitive polarographic wave was obtained at - 0. 35 V(vs. SCE). The second derivative wave height is linear with the concentration of iron in the range of 0. 5 -200 ug/L, and the detection limit is 0. 3 ug/L. Experimental results demonstrate that the wave is a paral catalytic current one with an adsorption character. The mechanism of the electrode reaction was also investigated. The ligand of the complex was reduced and its product was then oxidized by H2O2 to repro duce the ligand. Thus, a catalytic cycle was formed. The proposed method has been applied to the determination of iron in water sample and human hair.