Colloid titration of carrageenan and cellulosesulfate by cetylpyridinium chloride

Abstract

Technical grade carrageenan and sodium cellulosesulfate were determined by colloid titration with Cat-Floc (polydiallyldimethylammonium chloride) and cetylpyridinium chloride. As the titration proceeded, the solution became turbid gradually and near the end point the turbidity increased abruptly. The colloid titration curve was recorded with Metrohm potentiograph E 336 automatically by measuring transmittance at 420 nm using Metrohm spectrocolorimeter E 1009. At the same time sulfate content in carrageenan and sodium cellulosesulfate was measured gravimetrically as barium sulfate after hydrolysis of these esters. Colloid titration is useful for the determination of polycations or polyanions. In colloid titration principally polycations are titrated by polyvinylsulfate, a polyanionic titrant and polyanions by Cat-Floc, a polycationic titrant. In this study, it is shown that cetylpyridinium chloride, an ion association reagent, can be also useful as a colloid titration titrant for the determination of polysulfate, carrageenan and cellulosesulfate.