Demonstration of a simple, economical and practical technique utilising an imprinted polymer for metal ion sensing

This paper describes a simple, economical and practical optical sensor that has been developed using an ion imprinted polymer for detecting copper(II) ion using reflectance spectrometry. The imprinted polymer was synthesised in the presence of copper(II) ion using 4-vinylpyridine as monomer, 2-hydroxyethyl methacrylate as co-monomer, and ethylene glycol dimethacrylate as cross-linker in methanol via free radical polymerisation. The polymer formed was physically ground into fine particles, fabricated into a sensor probe and attached at the tip of an optical fibre bundle. The sensor operates optimally at pH 5 under constant stirring condition and has a linear dynamic range for copper(II) ion determination of 0.4-4.0 mM. The limit of detection for the sensor was 123 A mu M. The sensor has high selectivity for monitoring copper (II) ion in a multi-analyte environment, while also exhibiting better sensitivity compared to non-imprinted polymer. The response of the sensor can be regenerated fully without significant loss in its analytical signal for re-use. This reduces the consumable cost and at the same time making the operational process of such sensor simpler and more practical to be employed in real applications.