PVC membrane ion selective electrodes for determination of cationic surfactants

Electrochemical Sensors Laboratory, Department of Chemistry, University of Allahabad, Allahabad-211 002, Uttar Pradesh, India E-mail : mcc46@rediffmail.com, sunaina_ecsl@rediffmail.com Manuscript received 14 December 2010, revised 07 April 2011, accepted 20 April 2011 Two membrane electrodes were prepared, using sodium perchlorate-Aliquot 336, an ion-pair complex as electroactive material for one electrode and tertadecyl trimethyl ammonium bromide-sodium tetraphenyl borate as electro-active material in case of second electrode. The first electrode exhibits linear response for the surfactant cetyl trimethyl ammonium bromide in the concentration range 1 x 10-1 to 5 x 10-5 mol dm-3 with slope as 61.5 mV/decade change in the concentration and the second electrode exhibits linear response for the surfactant n-tetradecyl trimethyl ammonium bromide in the concentration range 2.5 x 10-3 to 1 x 10-5 mol dm-3 with slope 54.6 mV/decade. The working pH range and the response time for the first electrode is 4-10 and 15 s respectively while for electrode second the values are 2.5 to 6.5 and 30 s respectively. Selectivity coefficients for several cations have been determined