No abstract

A novel PVC membrane ion-selective electrode based on tribenzyltin(IV) dithiocarbamate [Sn(IV) -TBDTB] as neutral carrier was developed for thiocyanate (SCN À ) determination. The electrode exhibits a near-Nernstian response for SCN À with a slope of 62.8 AE 2.0 mV per decade over a wide concentration range 1.0 Â 10 À1 -2.0 Â 10 À6 mol L À1 and a detection limit of 1.0 Â 10 À6 mol L À1 in MES -NaOH buffer, pH 6.0, at 25 8C. The electrode prepared with 1.5 wt.% Sn(IV) -TBDTB, 32.5 wt.% PVC and 66.0 wt.% 2-nitrophenyloctyl ether (o-NPOE) shows optimal response characteristics. Anti-Hofmeister selectivity sequence for a series of anions shown by the electrode was as follows:. The useful pH range for the electrode was found to be 3 -7 with a response time 30 -40 s. The electrode has been used for direct determination of thiocyanate in wastewater with satisfactory results.