Highly Selective Potentiometric Determination of Ag(I) Using 1,2,4,5-tetrakis(8-hydroxyquinolinoxymethyl)benzene Based Coated-Wire Ion-Selective Electrode

摘要

A coated-wire silver ion-selective electrode (ISE) is constructed using 1,2,4,5-tetrakis(8-hydroxyquinolinoxymethyl)benzene (I) as neutral carrier in a poly(vinyl chloride) matrix plasticized with 2-nitrophenyl octyl ether. The best membrane composition (w/w) for the sensor is PVC 33%, plasticizer 63%, ionophore 4%. The sensor exhibited a linear Nernstian response over the concentration range 1 × 10~(-5) M to 1 × 10~(-1) M with a slope of 60±1 mV per decade change and a detection limit of 1 × 10~(-6) M. The working pH range is 3.5-7.5. The response time of sensor is 15 s and it can be used for at least 2 months without any significant divergence in potential. The sensor shows good selectivity over a number of alkali, alkaline earth and several transition and heavy metal ions. The electrode is used as an indicator electrode for the determination of Ag~+ in various synthetic samples and also used for the determination of SCN~-, CN~-, S~(-2) and I~- contents present in the sample solution.