Dysprosium(III) ion-selective electrochemical sensor based on 6-hydrazino-1,5-diphenyl-6,7-dihydropyrazolo- 3,4-d pyrimidine-4(5H)-imine
Dy( III) ion-selective electrode based on 6-hydrazino-1,5-diphenyl-6,7-dihydropyrazolo-[ 3,4-d] pyrimidine-4(5H)-imine (HDDPI) as an excellent sensing material was developed. The sensor exhibits a Nernstian behavior ( a slope of 19.6 +/- 0.3 mV per decade) over a wide concentration range ( from 1.0 x 10(-1) to 8.0 x 10(-7) M Dy) with a detection limit of 4.2 x 10(-7) M. The sensor response is independent of pH of the solution in the pH range 3.5 - 8.3. The sensor possesses the advantages of short conditioning time, fast response time (< 10 s) and in particular, good selectivity and sensitivity to the dysprosium ion in the presence of a variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The sensor also showed a great enhancement in selectivity coefficients for dysprosium ions, in comparison with the formerly mentioned dysprosium sensors. The electrode can be used for at least 10 weeks without any considerable divergence in the potentials. The proposed electrode was successfully used as an indicator electrode in potentiometric titration of Dy( III) ions with EDTA. The membrane sensor was also used in the determination of concentration of F - ions in some mouth washing solutions and in the Dy(3+) recovery from solution. Keywords: Potentiometry; Dysprosium sensors; ISEs; 6-Hydrazino-1,5-diphenyl-6,7-dihydropyrazolo-[ 3,4-d] pyrimidine-4( 5H)-imine; Metal ions complexation.