摘要
Selig用氧瓶分解有机硫化合物,生成的硫酸根用高氯酸铅作电位滴定,惜硫酸铅的溶解度较大,且F^-、Cl^-共存时干扰测定。Levins使聚乙二醇(PEG)及其衍生物与钡生成(钅羊)离子,以金属银电极作指示电极,用四苯硼酸钠(TPB钠盐)滴定,测定PEG及其衍生物含量。殷学锋等利用此反应在PEG存在下,以TPB电极作指示电极,用TPB钠盐返滴定钡测定镀铬液中的硫酸根。本文试验将此反应用于有机硫的测定,证明TPB液膜电极及硫化银电极均可用作电位滴定指示电极。本文并对不同分子量PEG的选择及其对电位滴定曲线的影响机理等问题作了初步探讨。
The potentiometric determination of sulphur in organic compounds has been studied. After combustion in an oxygen flask the resulting sulphate ions are precipitated by barium acetate, the excess of barium ions being titrated with sodium tetraphenylborate in the presence of polyethylene glycol(PEG). A number of PEG and PEG type nonionic surfactants have been compared as the complex-forming agent for barium ions, PEG 1540 being recommended as especially suitable for this purpose. The solubility of the percipitates was measured by UV spectrophotometry and the composition of some complexes was studied by potentiometric titration. The influence of molecular weight of PEG on the form of titration curves was interpreted by considering the solubility effect and complex composition. A tetraphenylborate ion electrode prepared from hexadecyltrioctylammonium tetraphenylborate as well as a silver sulphide electrode can be used as indicator electrodes. The mechanism of end point indication by the silver sulphide electrode was discussed.
出处
《分析化学》
SCIE
EI
CAS
1983年第5期343-347,共5页
Chinese Journal of Analytical Chemistry
