Open AccessDetermination of low chlorine content in organic compounds and polymers using an «Expert-006» coulometer
Author(s) -
Д. Х. Китаева,
А. Г. Буяновская,
О. Г. Левинская,
Sergei L. Dzvonkovskii
Publication year - 2018
Publication title -
zavodskaâ laboratoriâ. diagnostika materialov
Language(s) - English
Resource type - Journals
eISSN - 2588-0187
pISSN - 1028-6861
DOI - 10.26896/1028-6861-2018-84-7-16-20
Subject(s) - coulometry , chlorine , chloride , titration , chemistry , inorganic chemistry , ion , silver chloride , electrochemistry , electrode , organic chemistry
A method of visual mercurimetric titration of chloride ions is widely used in elemental microanalysis for determination of chlorine content in organic substances after their combustion in an oxygen-filled flask. However, when chlorine content is less than 0.5%, the mercurimetric method fails to provide essential accuracy, and a more sensitive method of chlorine coulometric titration by electrogenerated silver ions appeared favorable. We consider a possibility of determining the microgram content of chloride-ions in solutions using a digital coulometric analyzer («Expert-006» produced by «Econics-Expert» (Moscow)) supplemented with an electrolytic cell with silver electrodes. The coulometer was tested in different operation modes to select the optimal electrochemical parameters of ion chloride titration and develop a technique for coulometric determination of chloride ions which in combination with the preliminary burning of the analyzed substances in an oxygen-filled flask provides determination of the residual chlorine in organic matrices at a level of 0.1 – 0.5%. The proposed technique was used to determine the residual chlorine in a number of polymers. The relative error did not exceed 5% at chlorine concentrations of 0.16 – 0.28%.