5-(5-硝基-2-吡啶偶氮)-2,4-二氨基甲苯光度法同时测定钴和钯  

SIMULTANEOUS PHOTOMETRIC DETERMINATION OF COBALT AND PALLADIUM WITH 5-(5-NITRO-2-PYRIDYLAZO)-2,4-DIAMINO TOLUENE (5-NO_2-PADAT)

作　　者：王晓玲[1] 孙家娟[1] 杨连利[1] 刘彬[1] 杨秀洁 

机构地区：[1]咸阳师范学院化学系,咸阳712000 [2]咸阳师范学院

出　　处：《理化检验（化学分册）》2004年第10期581-583,共3页Physical Testing and Chemical Analysis(Part B:Chemical Analysis)

基　　金：陕西省教育厅专项科研计划项目(00JK132)

摘　　要：在3.0mol·L-1H2SO4介质中,钯(Ⅱ)与试剂可形成稳定的配合物,而钴(Ⅱ)与试剂在pH 5.5的HOAc-NaOAc介质中才能定量配合,配合物形成后,用硫酸酸化至一定酸度时则转变为另一稳定的深色配合物。同时两者的吸光度于586nm波长处具有良好的加和性。据此,建立了钴、钯同时测定的方法,已用于合成样中微量钴、钯的同时测定。The new reagent, 5-NO2-PADAT, reacts with Pd ( Ⅱ ) in a relatively high acidic medium of 3. 0mol · L-1 H2SO4 , to form a stable coordination complex with its absorption maxima at 591nm. The same reagent reacts with Co( Ⅱ ) in an acetate buffer medium of pH 5. 5 to form a stable coordination complex which keeps unchanged when the acidity of the solution is raised to 3. 0mol · L-1 H2SO4. The absorption maxima of the Co( Ⅱ) complex lies at 586nm. It is found that when the measurement is made at 586nm for both of the complexes of Pd( Ⅱ ) and Co( Ⅱ ), good additivity of the absorbances is obtained. Based on these facts, Co( Ⅱ ) and Pd( Ⅱ) can be determined simultaneously by taking two same aliquots of the sample solution, and carrying out the color reaction in one aliquot at 3. 0mol · L-1H2SO4 with its absorbance APd , and in another aliquot at pH 5. 5 and afterwards acidified to 3. 0mol · L-1 H2SO4 with its absorbance ACo+Pd. The absorbance of the Co( Ⅱ ) complex is obtained by the difference of ACo+Pd and APd. The proposed method has been applied satisfactorily to the analysis of simulated samples containing both Co( Ⅱ ) and Pd( Ⅱ ).

关 键 词：光度法 5-(5-硝基-2-吡啶偶氮)-2 4-二氨基甲苯 钴 钯 同时测定 

分 类 号：O657.32[理学—分析化学]