Fluorescence and Colorimetric Dual-Mode Ratiometric Sensor Based on Zr–Tetraphenylporphyrin Tetrasulfonic Acid Hydrate Metal–Organic Frameworks for Visual Detection of Copper Ions

Abstract

As a special heavy metal ion, copper ions (Cu2+) play an indispensable role in the fields of environmental protection and safety. Their excessive intake not only easily leads to diseases but also affects human health. Therefore, it is particularly important to construct a facile, effective, and highly selective Cu2+ probe. Herein, a novel Zr–tetraphenylporphyrin tetrasulfonic acid hydrate (TPPS) metal–organic framework (ZTM) was fabricated using TPPS as the ligand and exhibited strong red fluorescence with a high quantum yield of 12.22%. In addition, we designed a ratiometric fluorescent probe by introducing green fluorescein isothiocyanate (FITC), which was not subject to environmental interference and had high accuracy. When exposed to different amounts of Cu2+, the fluorescence emission at 667 nm from ZTMs is remarkably quenched, while that at 515 nm from FITC is enhanced, accompanied by a change in the solutions’ fluorescence color from red to green under a UV lamp. Besides, the ZTMs solutions display an excellent ratiometric colorimetric response for Cu2+ and produce an obvious color change (from green to colorless) that is visible to the naked eye. The fabricated ZTMs@FITC fluorescent probe exhibits distinguished performance for Cu2+ detection with linear ranges of 0.1 to 5 μM and 5 to 50 μM, as well as a low detection limit of 5.61 nM. Moreover, a colorimetric sensor based on ZTMs exhibits a good linear range from 0.1 to 20 μM for Cu2+ with the detection limit of 4.96 nM. Furthermore, the dual-signal ratiometric sensor has significant specificity for Cu2+ and is successfully applied for monitoring Cu2+ in water samples, which proves its practical application value in the environment and biological systems.

Metallochromic Hydrazone‐Based Chemosensor with Application in a Colorimetric Paper Strip for Selective Detection of Cu2+

“…Many colorimetric chemosensors have been developed for detection of copper ions, such as Schiff‐Bases, [35] pyrenes, [36] chromones, [37] and metal‐organic frameworks [38] . However, these chemosensors have shown disadvantages, such as sophisticated and expensive preparation procedures, poor selectivity, lower limit of detection, and difficult to operate under ambient conditions.…”

“…a* was increased and switched from negative to positive values [32][33][34] Many colorimetric chemosensors have been developed for detection of copper ions, such as Schiff-Bases, [35] pyrenes, [36] chromones, [37] and metal-organic frameworks. [38] However, these chemosensors have shown disadvantages, such as sophisticated and expensive preparation procedures, poor selectivity, lower limit of detection, and difficult to operate under ambient conditions. TCFH probes have been proved recently to be effective colorimetric chemosensors for the detection of heavy metals.…”

Fluorescence/Colorimetry/Smartphone Triple-Mode Sensing of Dopamine by a COF-Based Peroxidase-Mimic Platform

“…Moreover, the individual modes can be synergistic, increasing the applicability of the multi-mode sensors. The construction of optical multi-mode sensors for target analytes has aroused intense research interest in the fields of diagnosis, environmental monitoring, and food analysis. − …”

Novel NBN-Embedded Polymers and Their Application as Fluorescent Probes in Fe3+ and Cr3+ Detection

“…For example, iron plays an important role in many biological reaction processes, but its deficiency and excess can lead to various pathological obstacles [ 7 , 8 ]. Fluorescence sensors are often used in trace heavy metal ion sensing tools because of their convenient, rapid, and sensitive analysis [ 9 , 10 , 11 , 12 , 13 ]. Fluorescent probes can interact with metal ions through effects such as complexation and metal-driven chemical reactions, and at the same time, their fluorescence properties will also change, thereby achieving the effect of detecting metal ions [ 14 , 15 , 16 ].…”