摘要
研究了在H2 SO4 介质中 ,氯离子存在下 ,用甲苯萃取二甲基吲哚羰花青 (DIC)染料与Cr(Ⅵ )配合物的显色反应。基于此 ,建立了一种光度法测定微量Cr(Ⅵ )的新方法。结果表明在 0 .0 5～ 0 .3mol L的H2 SO4 介质中 ,甲苯对配合物的萃取率最高。最大吸收波长为 5 60nm ,摩尔吸光系数为 2 .5×1 0 5L·mol-1·cm-1,检出限为 4× 1 0 -9g mL ,有色溶液的吸光度与Cr(Ⅵ )量在 0 .0 1～ 2 .1mg L范围内符合比尔定律 ,加标回收率为 96.4 %～ 1 0 4 .8% (n =6) ,n(Cr(Ⅵ ) ) :n(Cl-)∶n(DIC) =1∶1∶1。
In H 2SO 4 medium and the presence of chloride ions,the complexation and extraction of Cr(Ⅵ) with dimethylindocarbocyanine(DIC) dye in toluene have been studied.Based on this,a novel spectrophotometric method for determining chromium(Ⅵ) was developed.The results show that the extraction of Cr(Ⅵ) complexation in toluene is the highest during extraction from the sulphuric acid medium in the range 0.05～0.3 mol/L H 2SO 4,the maximum absorption of the system is at 560 nm,and the molar absorptivity is 2.5×10 5L·mol -1 ·cm -1 independent from extractant and dye,the detection limit of the method is 4.0×10 -9 g/mL for Cr(Ⅵ) and Beer's law is obeyed for Cr(Ⅵ) in the range of 0.01～2.1 mg/L,the recovery of adding standard solution is 96.4 %～104.8 % ( n =6).It was found that the Cr(Ⅵ):Cl -∶DIC molar ratio is 1∶1∶1.The present method can be applied to the determination of chromium in FeNiCr alloys with satisfactory results.
出处
《化学通报》
CAS
CSCD
北大核心
2002年第4期274-277,共4页
Chemistry
基金
国家自然科学基金资助项目 (5 0 0 0 40 0 3)
