摘要
本文研究了β-环糊精(β-CD)及阳离子表面活性剂-β-CD 对 Al(Ⅲ)、Ga(Ⅲ)、In(Ⅲ)的铬天青 S 和埃铬菁 R 体系的作用及有关机理。结果表明,β-CD 对这些体系均无增敏作用、加入 CTMAB 或 CPB 后,产生不同程度的增敏作用,并有如下顺序:In(Ⅲ)-CAS(ECR)>Ga(Ⅲ)-CAS(ECR)>Al(Ⅲ)-CAS(ECR).其原因在于,阳离子表面活性剂的憎水基进入β-CD内腔,而另一端与显色螯合离子缔合,形成包合-缔合“桥式”结构,其极性比单独β-CD 增大,从而产生协同增敏作用。金属离子 In(Ⅲ)的离子半径最大,外层电子为18电子型,与显色剂形成的螫合离子极性也最大,与带异电的阳离子表面活性剂-β-CD 相互极化作用最强,故增敏作用最强。而 Al(Ⅲ)的离子半径最小,电子构型属惰气型,与阳离子表面活性剂-β-CD缔合作用最弱,故增敏作用也最低。
In this paper,the sensitizing effect of β-cyclodextrin(β-CD)on the chroma- zurine S(CAS)and erioehrome cyanine R(ECR)systems of Al(Ⅲ),Ga(Ⅲ),In(Ⅲ),with or without cationic surfaetant,such as cetyltrimethylammonium bromide(CTMAB)or cety- pyridinium aromide(CPB)and its mechanism were studied.The results indicated that β- CD did not cause any sensitizing effect on these systems without CTMAB or CPB.When optimum amounts of CTMAB or CPB were presented,the sensitivies of these systems were enhanced,and the sensitizing effect caused by CPB was higher than that by CTMAB.The sequence of the sensitizing effect was:In(Ⅲ)-CAS(or ECR)>Ga(Ⅲ)-CAS(or ECR)>Al(Ⅲ) -CAS(or ECR).The main reason of the sensitizing effect is that the inelusion complex was formed in which the hydrophobic part of the cationic surfaetant molecule is inserted into the cavity of β-CD,the other end is associated with the anionic complex formed by the metal ion with the organic chromogeic reagent.The polarity of CPB molecule is larger than that of CTMAB,thus the synergistic sensitizing effect of CPB-β-CD is higher than that of CTMAB-β-CD.The sequence of the ion radius of these three ions are:Al(Ⅲ)<Ga(Ⅲ) <In(Ⅲ),and then the polarity of their CAS and ECR complexes are also in this sequence. So that the synergistic sensitizing effect was the highest on In(Ⅲ)-system,the lowest on Al(Ⅲ)-system.
出处
《分析化学》
SCIE
EI
CAS
CSCD
北大核心
1991年第11期1234-1237,共4页
Chinese Journal of Analytical Chemistry
关键词
环糊精
埃铬菁R
显色反应
CAS
β-Cyclodextrin
Chromazurine S
Eriochrome cyanine R
Cationic surfactant
Synergistic sensitizing effect
