Determination of Sodium Dodecyl Sulfate via Turbidimetric Titration with Poly(Diallyldimethylammonium Chloride)

Titration of sodium dodecyl sulfate (SDS) solution with poly(diallyldimethylammonium chloride) (PDDA) results in the formation of colloidal dispersion and gradual increase of turbidity. The titration end point can be determined in different ways, depending on both titrant concentration and optical detector used. The maximum value of turbidity depends on concentration of the titrant solution. An immersion probe is applicable to measure turbidity changes only at low concentrations of the colloidal dispersion. An external optical sensor is well suitable at both low and high concentrations of PDDA titrant. Near to the equimolar ratio of the analyte and titrant, large floccules are formed and turbidity values undergo chaotic fluctuations. Calibration graphs for SDS determination are straight lines. Determination range is from 0.2 to 40 mg L-1.