Theoretical Modeling of Nanopore-Based Detection of Trace Concentrations of Cesium Ions in an Aqueous Environment

A conical poly(ethylene terephthalate) nanopore surface modified with a p-tert-butylcalix[4]arene crown is adopted to theoretically model the detection of trace concentrations of cesium ions in an aqueous environment through its ion current rectification (ICR) behavior. In particular, the background salt, the modification length of the modified layer, and the half cone angle of the nanopore are examined for their influence on the performance of the nanopore, which is measured by its ICR factor. The results of regression analysis for the dependence of the ICR ratio on the concentration of cesium ions suggest that the background salt appreciably influences the detection limit, and the optimum performance can be achieved by choosing a modified layer length of 1000 nm and half cone angle of 1°, where the widest detection range is [0.3, 500 nM] and the lowest detection limit is 0.3 nM. This detection limit is lower than those of the commonly used analytical tools such as atomic absorption spectroscopy, optical chemosensors, and electrochemical sensors.