Ni (II) - Selective Potentiometric Sensor Based on New Schiff base ligand, S-octyl-3-(furan-2-ylmethylene) dithiocarbazate

The construction and performance of a polymeric membrane electrode made with a new Schiff base called S-octyl-3-(furan-2-ylmethylidene) dithiocarbazate [L] for measuring nickel ions is described. The study revealed that the electrode performance is strongly influenced by the composition of the membrane matrix. The best results were achieved with a membrane made of (L) (2.5%): PVC (32.6%): DOP (62.4%): NaTPB (2.5%). This electrode gives a Nernstian response for nickel ions in concentrations between 4.2×10-8 and 1.0×10-1 M, with a detection limit of 2.1×10-9. It works well across a wide pH range from 2.5 to 10 and responds quickly, in about 9 seconds. The electrode also works in partially non-aqueous solutions containing up to 30% (v/v) methanol, ethanol, or acetonitrile and can be used for up to 3.0 months. It has excellent selectivity for Ni(II) over other mono-, bi- and trivalent cations. Its usefulness for analysis was tested by using it to measure nickel in various samples. The sensor's practical use was shown by using it as an indicator electrode in potentiometric titrations of Ni²+ against EDTA.