Liquid-membrane dicyanoargentate-sensitive electrodes based on quaternary ammonium salts

Several quaternary ammonium salts have been synthesized and comparisons made of their efficiency as exchange substrates in dicyanoargentate-sensitive electrodes. The electrode prepared from hexadecyltrioctylammonium dicyanoargentate shows the best performance characteristics and has been studied in more detail. Its Nernstian response range is 10(-1)-10(-4)M, the optimum pH range is 10.6-12.6, and the detection limit is 3 x 10(-5)M. It is suggested that the detection limit of the electrode is controlled by interference from cyanide ions, and the difference between detection limits obtained with the various electrodes is discussed in the light of this. Selectivity coefficients for various interfering ions have been determined and related to the extractability of the ions. The electrode has been applied to determination of silver in cyanide-containing plating solutions.