A novel dibasic phosphate-selective electrode based on Ferrocene-bearing macrocyclic amide compound

A new PVC membrane electrode for dibasic phosphate anion based on Ferrocene-bearing macrocyclic amide compound (L) has been prepared. The construction, response characteristic, selectivity and application of the electrode are investigated in detail. The best performance is exhibited by the electrode membrane containing 20 mol% TDMACl with o-NPOE as a plasticizer, and the electrode shows good selectivity towards HPO42− over a wide concentration range (1.0 × 10−2 to 1.0 × 10−5 M) with a Nernstian slope of 29.8 mV per decade at pH 9.0, and a detection limit of 2.2 × 10−6 M. It has a very short response time, less than 20 s, and can be used for at least 2 months without any divergence in response slope and linear range. The electrode displays high selectivity towards dibasic phosphate with respect to many other anions including Cl−, Br−, I−, NO3−, OAc−, and SO42−. The proposed electrode has been used as the indicator electrode in titration of phosphate with Ba(NO3)2 solution.