Lanthanum Monitoring by N,N'-1,3-phenylenedimaleimide based on Polymeric Membrane Electrode

A polymeric membrane based lanthanum selective electrode was developed using N,N'-1,3-phenylenedimaleimide. The best performance was recorded with a membrane composition of PVC: DBP: Ionophore: NaTPB as 33: 64: 2: 1 (w/w %). The Nernstian slope calculated from the calibration curve for La3+ sensor was 18.1 mV decade-1. The detection limit of the sensor was 3.16×10-9 M, in the linear concentration range of 1.0×10-2-1.0×10-8 M. Selectivity coefficients were calculated using Matched Potential Method. The interaction mechanism of the ionophore with different cations was estimated quantitatively by complex formation constant Kf values and qualitatively by FTIR spectroscopy and UV-Vis. spectrophotometry. The electrode was successfully applied to determine the fluoride content in the mouthwash and toothpaste sample.