阻抑催化动力学光度法测定水体中的痕量镍

研究了在pH9.2硼砂介质中,镍(II)对过氧化氢氧化溴甲酚紫褪色反应具有阻抑作用,聚乙二醇-200(PEG-200)对此反应体系有活化作用,据此建立了阻抑动力学光度法测定痕量镍(II)的新方法。试验考察了反应介质种类和用量、活化剂种类和用量、反应温度、反应时间、共存组分等因素的影响,确定了最佳试验条件。该方法的测定波长为590nm;活化剂为PEG-200;反应温度为沸水浴;反应时间为14min;线性范围为1.7×10-6g/L～1.4×10-4g/L;检出限为1.7×10-6g/L。所建方法用于环境水体中痕量镍(II)的测定,最大相对标准偏差为3.27%,加标回收率为95.5%～104.5%;所建方法与火焰原子吸收光谱法进行了对比试验,方法相对误差小于6.50%。

Determination of Trace Nickle in Water by Inhibitory Catalytic Kinetic Spectrophotometry

A simple and sensitive inhibitory kinetic spectrophometry for determining the micro amounts of nickle was developted.The method is based on minus catalytic of nickle ion on the oxidation of bromcresol purplet by hydrogen peroxide in borax medium. Major factors such as kinds and dosages of media,reagents and activators,the reaction temperature,the reaction time and coexisting irons are investigated,and the optimal experimental conditions are defined.Under the optumum experimental conditions,the wavelength for determination of this method was 590nm, the activator used was PEG-200, the experimental temperature was boiling water, the reaction time was 14min, the linear range was between 1.7×10-6g/L and 1.4×10-4g/L, and the detection limit was 1.7×10-6g/L. When the proposed method was applied to the determination of nickle in environment water,the maximum relative standard deviation was 3.27%,and the recoveries obtained were 95.5% to 104.5%. The maximum relative error compared with the FAAS was below 6.50%.