Potentiometric microsensor based on ion-imprinted polymer for the trace determination of cesium(I) ions

A cesium potentiometric microsensor based on magnetic ion-imprinted polymer (MIIP) has been developed for Cs(I) sensing. The core-shell structure Cs(I)-MIIP was synthesized by surface-imprinting technique, using functionalized magnetic Fe3O4@SiO2 microspheres, Cs(I) ion and carboxymethyl chitosan as supporter, template and functional monomers respectively. The resultant Cs(I)-MIIP was used as ionophore in the construction of the PVC membrane electrode to obtain a selective potentiometric microsensor toward Cs(I) ions. The fabricated sensor exhibited a highly sensitive Nernstian response (60.2 mV/decade) over the concentration range of 1 × 10−6 to 1 × 10−1 M of Cs(I). The response time of the microsensor was considerably short (less than 3 s) and its detection limit was determined as 3.0 × 10−7 M. The microsensor was effectively performed in the pH range of 4–6, and revealed desirable selectivity over a wide variety of other cations including alkali, alkaline earth and heavy metals. The proposed microsensor was also used for the determination of Cs(I) contents in the environmental water samples. The potentiometric results were in good harmony with the results obtained by the ICP-MS method.