摘要
本文探讨了Y^(3+)与碱性染料罗丹明B络合物的极谱行为。在NH4Cl底液中,二苯胍存在下,罗丹明B在-1.50伏(SCE)附近有一个大而稳定的极谱吸附还原波,Y^(3+)使示波导数波降低。在最佳实验条件下,在1×10^(-7)-1×10^(-6)M的范围内Y^(3+)浓度与波高降低有良好线性关系。重稀土行为相似,可能用于测定重稀土总量。通过i-t曲线,循环伏安图、比较dc、dpp、示波极谱常规波和导数波,研究了体系的还原机理。Y^(3+)与罗丹明B和二苯胍可能形成离子缔合络合物,强烈吸附并占据滴汞表面。络合物在罗丹明B还原波后还原,致使罗丹明B本身的波降低。在dc和示波常规波中。两波不能分开,在dpp中因电压扫描慢,无良好线性关系。只有在示波导数波上表现为一种灵敏的极谱波。
This paper reports the polarographic behavior of the complex of Y^(3+)with basic dye rhodamine B.Near-1.5V(SCE)rhodamine B has a large adsorptive single sweep polarographic wave in the presence of ammonium chloride and diphenylg-uanidine.Y^(3+)decreases the height of this derivative wave.Under the optimum conditions,such as 0.4.M ammonium chloride,8.0×10^(-5)M rhodamine B,1.0×10^(-4)M diphenylguanidine,pH 4.5-5.0,there is a linear relationship between 1×10^(-7)-l×10^(-6)M Y^(3+)and the decrease of the wave heights.Heavy rare earth elements behave similarly as Y^(3+),thus the total amount of them may be determined.The mechanism of this system has been studied by means of dc,dpp,single sweep normal and derivative polarographys.The results indicated that Y^(3+)may form an ion-association complex with rhodamine B and diphenylguanidine as shown in the following.The complex adsorbs strongly and occupies the partial surface area of the mercury drop.The complex reduces at more negative potential than rhodamine B,thus the wave height of rhodamine B itself decreases correspondingly.The two steps can’t be separated In dc and single sweep normal polarograms and they interfere each other in dpp owing to the slow scan rate of pulse polarograph,there is no good linear:relatjonskip between the concentration and wave height.A sensitive wave only exists in the single sweep derivative polarography.
作者
焦奎
高小霞
Jiao Kui;Gao Xiaoxia(Kao Sheau-shya)(Chemistry Department,Peking University,Beijing)
出处
《高等学校化学学报》
SCIE
EI
CAS
1982年第3期327-335,共9页
Chemical Journal of Chinese Universities
