Fabrication of Ion-Selective Electrodes (ISEs) for Detection of Some Metal Ions in Aqueous Solutions

Abstract

Ion-selective electrodes made from Cd, Pb, Na, and Ca ions were synthesised for use as a potentiometric electrochemical sensor of water pollution detection. The electrodes consisted of Cd, Pb, Na, and Ca ions as ion exchangers and polyvinyl chloride and tris (2-ethylhexyl) phosphate as plasticisers. The response properties of these electrodes, UV-visible spectra of samples, calibration curve, lifetime, limit detection, concentration range and pH effect were studied. The limit of detection of (Cd, Pb, Na, and Ca) were (0.000693, 0.007454, 36.5167, and 5.496729), and the correlation coefficients were about 0.9482, 0.9803, 0.999, and 0.9861, and the life time approximately were 25, 25, 1, and 1 day, respectively. The best sensitivity was observed at a pH range of 6 to 10 for Cd and of 5 to 10 for Pb, while the electrodes of Na and Ca don't work within the specific pH range due to rapid electrode oxidation, which reduces their efficiency. The proposed electrodes were successfully applied in the detection of heavy metals in water.