Titrimetric determination of anionic surfactant content in anioniconionic surfactant mixture solution by anionic surfactant selective electrode

摘要

A new polyvinyl chloride (PVC) membrane electrode fordetermining the concentration of sodium dodecylsulfate (SDS) based ona neutral ion pair complex of dodecyltrimethylammonium-dodecylsulfate(DTA^+DS^-) as ionophore is described in this paper. The constructionand characteristic performance of the PVC membrane electrode displaysa Nernstian slope of --56.9 pm 0.3 mV/decade in the concentrationrange of 2.0 imes 10^{-6} to 3.2 imes 10^{-3} mol L^{-1} and adetection limit of 1.6 imes 10^{-6} mol L^{-1}. The lifetime of theelectrode is more than 3 months without showing significant change inthe values of slope or linear concentration range. The electrode haswide pH range of application and short response time. The electrodeshows selective response to DS^- and poor response to common anionsexcept DBS^-. The electrode was used as an end point indicatorelectrode for the determination of SDS content in sodiumdodecylsulfateonylphenol ethoxylates (SDS/NP-10) mixture solution bypotentiometric titration using Hyamine standard solution as titrant.The maximum mol ratio (n_{(NP-10)}: n_{(SDS)}) when SDS cannot bedetermined in SDS/NP-10 mixture solution can be obtained.