Co(Ⅱ)-4-(2-吡啶偶氮)间苯二酚-聚乙二醇-(NH_4)_2SO_4萃取体系的研究和应用  

Study on extraction system of Co(Ⅱ)-4-(2-pyridylazo) resorcinol-polyethylene glycol-(NH_4)_2SO_4 and application

作　　者：侯明[1] 王初丹[1] 

机构地区：[1]桂林工学院材料与化学工程系,桂林541004

出　　处：《分析试验室》2008年第6期17-20,共4页Chinese Journal of Analysis Laboratory

基　　金：广西自然科学基金(桂科自0679005)项目资助

摘　　要：研究了Co（Ⅱ）-4-（2-吡啶偶氮）间苯二酚（PAR）-聚乙二醇（PEG）-（NH4）2SO4体系的萃取行为及最佳分相条件，建立了测定生物样品中微量钴的非有机溶剂萃取光度法。结果表明，在pH8．6的六次甲基四胺缓冲溶液中，在（NH4），SO4存在下，Co（Ⅱ）-PAR的络合物可被PEG相富集萃取。在PEG相中络合物的最大吸收波长为519nm，表观摩尔吸光系数4．68×10^4L·mol^-1·cm^-1，钴量在0～1．8μg／mL范围内服从比尔定律。方法已用于粮食、茶叶等生物样品中痕量钴的测定，回收率97．2％～103％。The extraction behavior of the complex of cobalt （ Ⅱ ） with 4-（2-pyridylazo）-resorcinol in the system of polyethylene glycol （PEG）-（NH4）2SO4 was studied and the proper conditions of phase separation of PEG and water were selected. A new spectrophotometric method based on liquid-liquid extraction without organic solvent was established. In buffer solution of （CH2）6N4 at pH 8.6, the cobalt（ Ⅱ）-4-（2-pyridylazo）-resorcinol complex can be extrac- ted into the PEG phase and quantitative separation of Co^2＋ from Cu^2＋ , Fe^3＋ , Ni^2＋ , Mo（ Ⅵ ） and Y（ Ⅴ ） is realized by adding NH4F and EDTA as the masking agent. The maximum absorption wavelength of the complex is 519 nm. The apparent molar absorptivity is 4.68 × 10^4 L· mol^-1 ·cm^-1. Beer＇s law is obeyed for Co（ Ⅱ ） in the range of 0- 1.8 μg/mL. The method was applied to the determination of trace cobalt in the rice and tea samples with satisfactory results.

关 键 词：钴 聚乙二醇 4-(2-吡啶偶氮)间苯二酚 光度法 

分 类 号：O657.3[理学—分析化学]