| Surfactant ion-selective membrane electrodes, the electrochemistry sensors, have aroused the great interests of many scientists because of its function of quantitative analysis and application in physical chemistry of surfactants. In this paper, the traditional anionic surfactant ion-selective membrane electrode and modified anionic surfactant ion-selective membrane electrode were prepared and their application were investigated.Using the sediment of mixed sodium dodecyl sulfate (SDS) and cetyltrimethyl -ammonium bromide(CTAB)as the electrical active material, a sodium dodecyl sulfate ion-selective membrane electrode was prepared. Application condition of the electrode was investigated. The results show that at 25℃, the detection limit for SDS is 2.2×10-6mol/L, the concentration range of linear response is from 3.0×10-6mol/L to 6.3×10-3mol/L and the response slope is 55.5mV/decade. The membrane electrode can be used in pH value from 5 to 11 exhibiting excellent stability and repeatability. The response time of the electrode is 90s, and it can use around 30 times.With the self-made surfactant ion-selective membrane electrode, the concentration of anionic surfactant SDS or sodium fatty alcohol ether sulfate (AES) could be determined through potentiometic titration at the presence of fatty alcohol polyoxyethylene ether (AEO9). The mole ratio of AEO9:SDS and AEO9:AES should be less than 2:1 and 1:2 to get reasonable results. The adsorption of SDS on alumina was also examined with the surfactant ion-selective electrode. A S-type adsorption isotherm was obtained. It proves that the adsorbance of SDS on alumina was greatly depended on the solution pH value.The polyvinyl chloride (PVC) was modified by N-methylpiperazine, then was quaternized with methyliodide. The modified PVC was analyzed by potentiometic titration in non-aqueous system with perchloric in acetic acid as the titrant. It was found that 1%( mole fraction) PVC unit was aminated, and obout 50%(mole fraction) of aminated PVC was quaternized, the tertiary amine group joined on to the main chain was not quaternized because of steric effect. The structure of modified PVC was characterized by 1HNMR. The renewed surfactant ion-selective membrane electrode was prepared with the modified PVC. Application condition of the electrode was investigated. At 25℃, the detection limit for SDS is 1.8×10-6mol/L, the concentration range of linear response is from 2.6×10-6mol/L to 6.5×10-3mol/L and the response slope is 58.5mV/decade. The membrane electrode can be used in pH from 4 to 12 exhibiting excellent stability and repeatability. The response time of the electrode is 60s. The selectivity of the electrode indicates that familiar inorganic ions can hardly interfere in the electrode measurement, but interference from other anionic surfactants such as Sodium dodecylbenzenesulfonate (SDBS) are significant. The electrode can use 80 times, compared with the traditional one, the lifetime has been improved.
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