Use of triphenylmethane dyes for the spectrophotometric determination of polymer flocculauts in aqueous solutions

摘要

The interaction of anionic forms of triphenylmethane dyes (TPM) with cationic polymer flocculants (e.g., with polydiallyldimethylammonium chloride (PC)) yields inextricable ion pairs. This leads to a shift of absorption bands or a redistribution of their intensities in the TPM spectra and can be used for the spectrophotometric determination of microgram amounts of flocculants in aqueous solutions. Among 14 studied TPMs, erythrosine is the most promising dye. The corresponding procedure allows the determination of PC at a level of the maximum permissible concentration. To decrease the effect of impurities, the use of the standard addition method is recommended.