CTMAB存在下铬（Ⅲ）与PAR及三乙醇胺的显色反应

COLOR REACTION OF CHROMIUM(Ⅲ) WITH PAR AND TEA IN THE PRESENCE OF CTMAB

研究了在溴化十六烷基三甲基铵（ＣＴＭＡＢ）存在下，铬（Ⅲ）与４－（２－吡啶偶氮）－间苯二酚（ＰＡＲ）及三乙醇胺（ＴＥＡ）的显色反应。结果表明在ｐＨ６．８～７．８的三乙醇胺及其盐酸盐的缓冲体系中，经沸水浴２０ｍｉｎ，Ｃｒ（Ⅲ）－ＰＡＲ－ＴＥＡ显色完全，ＣＴＭＡＢ有较好的增敏及稳定作用；λ_（ｍａｘ）＝５４０ｎｍ，ε_（５４０）＝５．６×１０~４Ｌ·ｍｏｌ^（－１）·ｃｍ^（－１），Ｃｒ（Ⅲ）含量在０．８－８×１０^（－４）ｇ·Ｌ^（－１）范围内吸光度遵从比尔定律。

Color reaction of chromiun(Ⅲ) with PAR and TEA in the presence of cetyltrimethylammonium bromide and its applications are repoted.In the buffer solution of triethanolammonium and its chloride from PH6.8 to 7. 8,the color development of Cr(Ⅲ)-PAR-TEA is complete after 20 min heating in water-bath.The effect of increasing and stabilizing absorbance in the presence of CTMAB is observed.The maximum absorbance of the color complex is at 540 nm,molar absorptivity is 5.6×10￣4L·mol￣(-1) Beer's law is obeyed over the range 0.8 -8+10￣(-4) gL￣(-1) chrominm(Ⅲ) The sensitivity and selectivity of this method are satisfied for the determination of microamount chromiurn (Ⅲ) in foods.