The derivative of quinaldic acid, 8-(dodecyloxy)quinoline-2-carboxylic acid, has been used as an ionophore in the development of a lead(II)-selective electrode. Solvent extraction studies showed that this compound is selective for lead(II) and copper(II) over a variety of divalent and monovalent metals. Liquid polymeric membranes of plasticized poly(vinyl chloride) were prepared using bis-(2-ethylhexyl) sebacate as the plasticizer and the lead(II) complex of 8-dodecyloxy quinoline-2-carboxylic acid as the ionophore. The effect of several parameters, such as content of ionophore in the membrane, pH of the sample solution, and electrode conditioning was investigated. When optimized, the electrode responded in a near-Nernstian fashion to lead(II) and the detection limit was found to be 5.0 × 10-7 M. The electrode is selective for Pb2+ over Cu2+, Al3+, Mn2+, Ni2+, Co2+, Zn2+, Mg2+, Ca2+, Na+, K+, with Hg2+ and Cu2+ the most interfering metal ions.
|Publication status||Published - 19 Feb 2001|
- Ion selective electrode
- PVC membrane
- Quinaldic acid
- Solvent extraction