ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Coulometric Bromometric Titration of Free
and Coordinately Linked Cyanides
J. Mocák, D. I. Bustin, and M. Žiaková
Department of Analytical Chemistry, Slovak Technical University,
Abstract: The conditions of coulom9tric bromometric determination of cyanides
in weak alkaline medium of the borate buffer solution are described. It is
possible to titrate free cyanides and the cyanides linked coordinately in
Cr(CN63-)jp and Cr(CN)6N03-. The equivalence point of titration is indicated
biamperometrically. The presence of air oxygen influences the results of free
cyanide determination. The reaction scheme is discussed on the basis of
different results obtained in bromometric oxidation of cyanides and cyanide
The determinations were performed in the concentration range from
94.8 to 2020 μg of KCN. The accuracy of determination corresponding
to 95% probability is expressed for 2020, 776, and 94.8 μg of KCN by the
reliability interval of i 10.1, ± 7.5, and ± 1.3 μg of KCN, respectively.
The coulometric bromometric titration of cyanide is especially suitable for
the determination of cyanides in the presence of chlorides and bromides.
Chlorides do not interfere even if the ratio Сl-/CN- has the value of 2.7 X 104.
Bromides do not interfere provided that the ratio Br-/CN- does not exceed
the value of 5.9 X 104.
Full paper in Portable Document Format: 262a126.pdf
Chemical Papers 26 (2) 126–132 (1972)