Luminous Insights: Exploring Organic Fluorescent "Turn-On" Chemosensors for Metal-Ion (Cu+2, Al+3, Zn+2, Fe+3) Detection

There are several metal ions that are vital for the growth of the environmental field as well as for the biological field but only up to the maximum limit. If they are present in excess, it could be hazardous for the human health. With the growing technology, a series of various detection techniques are employed in order to recognize those metal ions, some of them include voltammetry, electrochemical methods, inductively couples, etc. However, these techniques are expensive, time consuming, requires large storage, advanced instrumentation, and a skilled person to operate. So, here comes the need of a sensor and it is defined as a miniature device which detects the substance of interest by giving response in the form of energy change. So, from past few decades, many sensors have been formulated for detecting metal ions with some basic characteristics like selectivity, specificity, sensitivity, high accuracy, lower detection limit, and response time. Detecting various metal ions by employing chemosensors involves different techniques such as fluorescence, phosphorescence, chemiluminescence, electrochemical, and colorimetry. The fluorescence technique has certain advantages over the other techniques. This review mainly focuses on the chemosensors that show a signal in the form of fluorescence to detect Al+3, Zn+2, Cu+2, and Fe+3 ions.

Facile Synthesis of Nitrogen-Doped Carbon Quantum Dots with Chitosan for Fluorescent Detection of Fe3

A facile, economical, and one-step hydrothermal method was used to prepare highly luminescent nitrogen-doped carbon quantum dots (N-CQDs) with chitosan as both carbon and nitrogen sources. The as-prepared N-CQDs have an average size of 2 nm and exhibit excitation wavelength-dependent fluorescence with a maximum excitation and emission at 330 and 410 nm, respectively. Furthermore, due to the effective quenching effect of Fe³⁺ ions, the prepared N-CQDs can be used as a fluorescent sensor for Fe³⁺ ion-sensitive detection with a detection limit of 0.15 μM. The selectivity experiments revealed that the fluorescent sensor is specific to Fe³⁺ even with interference by high concentrations of other metal ions. Most importantly, the N-CQD-based Fe³⁺ ion sensor can be successfully applied to the determination of Fe³⁺ in real water samples. With excellent sensitivity and selectivity, such stable and cheap carbon materials are potentially suitable for the monitoring of Fe³⁺ in environmental application.

Fluorescent organic nanoparticles (FONs) as convenient probes for metal ion detection in aqueous medium

Fluorescent organic nanoparticle (FON)-based chemosensors are emerging as a valuable tool for the fast and accurate detection of metal ions in aqueous media. In this review, we highlight the recent developments in this field.

A new fluorescent macrocyclic nano-chemosensor for Fe3+ and I− in aqueous solution

A fluorescent nano-chemosensor, capable of detecting Fe³⁺ and I⁻ in aqueous media, has been designed and synthesized.

Design and synthesis of a new class of 2,4-thiazolidinedione based macrocycles suitable for Fe3+sensing

Three 2,4-thiazolidinedione based macrocycles, which are very good Fe³⁺sensors in aqueous-ethanol medium, have been synthesized. X-ray crystallography, DFT calculations and MEP analysis have been used for their structural confirmation and for understanding their behavior towards Fe³⁺.