铌钼杂多酸的极谱行为及其应用于铌的测定  

Polarographic Behavior of Niobium-Molybdate Heteropoly Acid and Its Application for the Determinaiton of Niobium

作　　者：李建平[1] 姜小林 

机构地区：[1]桂林工学院应用化学系,桂林541004

出　　处：《分析化学》1996年第9期1065-1068,共4页Chinese Journal of Analytical Chemistry

摘　　要：在pH2．5的硫酸、抗坏血酸溶液中，铌与钼形成了具有电活性的铌钼蓝杂多酸，并在pH8．8的NH3－NH4Cl溶液中可在滴汞电极上于－1．10V（vs．SCE）产生一灵敏的还原波。导数波高与铌量在0．005～0．4mg／L范围内呈线性关系。研究了极谱波性质，证明其为吸附波，电极反应属于准可逆。求得电极反应中电子转移数及质子转移数均为2。应用本法已测定了合金钢标样中的铌。In H2SO4 solution (pH 2. 5 ) containing ascorbic acid, niobium (Ⅴ) reacts with molybdate to form heteropoly blue acid, and then a sensitive wave appears at - 1. 10 V (vs.SCE) in NH3-NH4Cl buffer solution (pH 8. 8). The derivative peak height is directly proportional to niobium concentration in the range of 0. 005~0. 4 mg/L. The detection limit is 0. 002 mg/L. This polarographic wave has an adsorptive character and the electrode reaction is quasi-reversible. This method is sensitive, accurate and rapid and has been used to determine niobium in reference samples of alloyed steel.

关 键 词：铌 铌钼杂多酸 极谱法 硫酸 抗坏血酸 合金钢 

分 类 号：O614.512[理学—无机化学] O657.13[理学—化学]