Dual colorimetric and fluorometric monitoring of Cd²⁺ and Hg²⁺ ions in water using functionalized Zrmetal–organic frameworks chemosensors

Abstract

Chemical sensor based on NH 2 ‐UiO‐66(Zr) have been developed for rapid detection of Cd 2+ and Hg 2+ ions. The developed 2HA = N‐UiO‐66(Zr) sensor was prepared by the condensation of the Zr‐metal–organic framework (MOF) with 2‐hydroxyacetophenone. The NH 2 ‐UiO‐66(Zr) and 2HA = N‐UiO‐66(Zr) sensor were characterized by scanning electron microscopy (SEM), X‐ray diffractometer (XRD), Fourier transform infrared (FT‐IR), X‐ray photoelectron spectroscopy (XPS), and Brunner–Emmet–Teller (BET). The characterization results shown that 2‐hydroxyacetophenone was successfully introduced on the Zr‐based MOF and that the pore structure of 2HA = N‐UiO‐66(Zr) sensor mainly contains mesopores. Many experimental studies have been conducted to find out the optimum conditions for colorimetric and fluorometric determining of the Cd 2+ and Hg 2+ ions by the 2HA = N‐UiO‐66(Zr) sensor. The response time, for the sensor, that is necessary to achieve a steady spectroscopic signal was less than 30 s. The suggested methods were validated in terms of the lowest limit of detection (LOD), the lowest limit of quantification (LOQ), linearity, and precision according to International Conference on Harmonization (ICH) guidelines. As a result, the 2HA = N‐UiO‐66(Zr) sensor was successfully used to determine Cd 2+ and Hg 2+ ions in a variety of tap water samples with great sensitivity and selectivity.