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Cobaltothiocyanate colorimetric analysis for homologous polyoxyethylated alkyl amides
Author(s) -
Lin John T.,
Cornell Donald G.,
Micich Thomas J.
Publication year - 1986
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02553089
Subject(s) - colorimetry , ethylene oxide , chemistry , alkyl , homologous series , solvent , chromatography , nonionic surfactant , pulmonary surfactant , organic chemistry , biochemistry , polymer , copolymer
Cobaltothiocyanate colorimetry has been used for quantitative analysis of polyethoxylates in biodegradation and environmental studies. Usually, the calibration parameters (slope and intercept of a calibration line) for the cobaltothiocyanate colorimetry are dependent on ethylene oxide chain length. To make the colorimetric method useful for polyoxyethylated surfactant mixtures, where the average chain length is polydispersed, a condition was found yielding parameters independent of chain length in a homologous series of polyethoxylates within a limited chain length range. The dependency can be correlated to the thermodynamics of the ethylene oxide‐cobaltothiocyanate complexation and the solvent extraction.