摘要
目前利用褪色反应测铬的光度分析法大多灵敏度不高。通过研究三氯偶氮氯膦与Ｃｒ２Ｏ２－７的褪色反应，发现其在硝酸介质中具有高灵敏的褪色反应，其摩尔吸光系数ε＝１．１×１０５，是目前测铬的最灵敏的方法之一。研究发现该体系在５５０ｎｍ处具有最大吸光度ΔＡ，在硫酸、盐酸介质中加热３０ｍｉｎ时褪色不明显，在硝酸介质中加热１０ｍｉｎ已褪色完全。在ＨＮＯ３（Ｖ（ＨＮＯ３）∶Ｖ（Ｈ２Ｏ）＝１∶３）用量为３．０～５．５ｍＬ，０．５ｇ／Ｌ三氯偶氮氯膦溶液的用量为２．０～３．５ｍＬ，沸水浴加热８～１１ｍｉｎ时，褪色完全。本研究选取ＨＮＯ３４．５ｍＬ（Ｖ（ＨＮＯ３）∶Ｖ（Ｈ２Ｏ）＝１∶３），三氯偶氮氯膦溶液２．５ｍＬ，沸水浴加热９ｍｉｎ。Ｃｒ（Ⅵ）质量浓度在０～０．４８μｇ／ｍＬ内符合比耳定律，回归方程为ΔＡ＝０．９７２５ρ（μｇ／ｍＬ）＋０．０１７３，相关系数γ＝０．９９６８。对１８种共存离子的干扰进行了测定，Ｆｅ２＋，Ｆｅ３＋，ＭｎＯ－４的干扰可在溶样时除去。用于合金钢及水中的微量铬的测定结果令人满意。
The fading reaction trichloro chlorophosphonazo with Cr 2O 2- 7 was studied It is found that the reaction has high sensitivity in the medium of nitric acid,and the molar absorptivity is 1 1×10 5 It is one of the best method for the determination of chromium at present The Beers law is abided the range of 0～0.48 μg/mL Cr(Ⅵ)content,and the regression equation is:Δ A =0 9725ρ(μg/mL)+0 0173 The disturbances of 18 kinds of ions was tested,in which the disturbances of iron can be avoided in the dissolving of samples This method can be applied to the determination of trace chromium in alloy steel and water
出处
《山东建材学院学报》
1998年第2期112-114,共3页
Journal of Shandong Institute of Building Materials
关键词
光度法
褪色反应
三氯偶氮氯膦
铬
spectrophotometric method
fading reaction
trichloro chlorophosphonazo
chromium(Ⅵ)
