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Coated wire electrodes in the analysis of surfactants of various types: An overview
Author(s) -
Vytřas Karel
Publication year - 1991
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.1140030416
Subject(s) - tetraphenylborate , sodium tetraphenylborate , titration , chemistry , inorganic chemistry , cationic polymerization , polymer chemistry , organic chemistry , ion
Simple ion‐selective electrodes of the coated wire type were prepared using an ordinary aluminum wire conductor, coating the central wire with the membrane formed by plasticized poly vinyl chloride. These simple and inexpensive electrodes can be used advantageously as sensors in ion pair formation‐based titrations of surfactants of various types. Cationic surfactants are titrated using sodium tetraphenylborate titrant yielding titration curves with sharp potential breaks. For the determination of nonionic surfactants containing poly oxyalkylene chains, the method used was based on the precipitation of ternary compounds with sodium tetraphenylborate in the presence of bivalent metal ion with an ionic radius higher than 100 pm. Also ampholytic surfactants can be titrated directly with tetraphenylborate in acidic solutions, in which they are cationic; but for the determination of some of them, back‐titration is more convenient. Anionic surfactants are titrated using lipophilic cationic titrants such as quaternary ammonium or pyridinium salts. Some mixed systems can also be analyzed. Several examples are given.