Re-examination of the microanalysis of non-ionic surfactants that contain polyoxyethylene chains by the method involving solvent extraction of the thiocyanatocobaltate(II) complex

Abstract

The microanalysis of surfactants of the type R—(O—CH2—CH2)nOH by use of a colorimetric method involving solvent extraction of the thiocyanatocobaltate(II) complex was re-examined for the pure compounds and for mixtures. It was concluded that Beer's law was not always obeyed, especially when the composition of the mixture was simple, and that the shape of the calibration graph was markedly dependent on the composition. The limits of the practical application of the method were considered.