4.1 - Poly-binaphthyl-20 crown-6 as Receptor Based Molecule Selective Potentiometric Electrodes for Molecules Containing 1,2-Dihydroxybenzene Moieties

Abstract

This chapter discusses a study examining poly-binaphthyl-20-crown-6 as receptor based molecule selective potentiometric electrodes for molecules containing 1,2-dihydroxybenzene moieties. A new potentiometric electrode for the determination of 1,2-dihydroxybenzene moieties such as catecholamines, known as important neurotransmitter, was constructed by means of simple electrochemical polymerization. The synthesized poly-binaphthyl-20-crown-6 was employed as the sensing material of the electrode and Pt electrode served as substrate. The response of the new electrode is based on molecular recognition. The potentiometric response is dependent of the pH of the solution and nature of the buffer medium. The linearity of LogC vs E curve ranges from 10−7–2 × 10−6 M with supper Nernstian slope of 110 to 130 mV/decade, and detection limit of 6 × 10−8 M in phosphate buffer (0.1 M, pH 9.4). The potentiometric electrode showed virtually no interfering inorganic ions and circumvented the interference from ascorbic acid, which is often met using amperometric methods. The response mechanism of the present electrode is discussed, supported by results from SEM and X-ray analysis.