Determination of cationic polyelectrolytes using a photometric titration with crystal violet as a color indicator

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19 Citations (Scopus)


The reaction of the cationic dye, crystal violet (CV) with the anionic polyelectrolytes such as potassium poly (vinyl sulfate) (PVSK) results in a decrease of the absorbance of CV at the maximum absorption wavelength (590 nm). This change of the absorption spectra of the CV has been already applied to the determination of anionic polyelectrolytes using flow injection analysis method. In this paper, CV was applied to the indicator for the determination of cationic polyelectrolytes such as poly (diallyldimethylammonium chloride) (Cat-floc) by photometric titration, using a PVSK solution as a titrant. The end-point of the titration is detected as the break point of the titration curve. A linear relationship between the concentration of cationic polyelectrolyte and the end-point volume of the titrant exists in the concentration range from 0 to 5 × 10-5 eq. mol dm-3 for Cat-floc, glycol chitosan and methylglycol chitosan. The effects of the concentration of CV and coexisting electrolytes in the sample solution and the effect of pH of the sample solution on the degree of the change of absorbance at the end-point were also examined.

Original languageEnglish
Pages (from-to)659-666
Number of pages8
Issue number4
Publication statusPublished - 2003 Mar 10
Externally publishedYes


  • Cationic polyelectrolytes
  • Colloidal titration
  • Crystal violet
  • Glycol chitosan
  • Methylglycol chitosan
  • Photometric titration
  • Poly (diallyldimethylammonium chloride)

ASJC Scopus subject areas

  • Analytical Chemistry


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