Naked-eye Detection of Hg2+ in Practical Applications Using a Highly Selective and Sensitive Fluorescent Probe

Accurate and rapid mercury susceptibility detection in aquatic samples using fluorescent probe integrated rhodamine with pyridyl isothiocyanate

Mercury, one of the various harmful metals, is particularly significant in affecting aquatic organisms, currently gaining more attentions and sparking discussions. In response to the limitations of traditional detections, fluorescent probes have emerged as a promising solution with some advantages, such as weaker background interference, shorter processing time, higher accuracy. Thus, a novel fluorescent probe, FS-Hg-1, has been developed for assessing mercury ion (Hg2+) concentrations in aquatic products. This probe displays specific recognition of mercury ions in fluorescence spectra. Notably, FS-Hg-1 exhibits a distinct color change to pink when combined with Hg2+ (with a 948-fold increase in absorption at 568 nm) and a substantial fluorescence change towards Hg2+ (361-fold increase, excitation at 562 nm, emission at 594 nm) in N, N-dimethylformamide. The probe boasts a detection limit of 0.14 μM and rapid reaction with Hg2+ within 10 s, showing an excellent linear correlation with [Hg2+] in the range of 0 to 10 μM. Through thorough analysis using FS-Hg-1, the results align with those from the standard method (P > 0.05), with spiked recovery rates ranging from 108.4% to 113.2%. With its precise recognition, low detection limit, and remarkable sensitivity, this fluorescent assay proves effective in mercury concentration determination in aquatic samples without interference. The potential of FS-Hg-1 is promising for speedy detection of residual Hg2+ and holds significance in ensuring food safety.

Recent Progress on Fluorescent Probes in Heavy Metal Determinations for Food Safety: A Review

One of the main challenges faced in food safety is the accumulation of toxic heavy metals from environmental sources, which can sequentially endanger human health when they are consumed. It is invaluable to establish a practical assay for the determination of heavy metals for food safety. Among the current detection methods, technology based on fluorescent probes, with the advantages of sensitivity, convenience, accuracy, cost, and reliability, has recently shown pluralistic applications in the food industry, which is significant to ensure food safety. Hence, this review systematically presents the recent progress on novel fluorescent probes in determining heavy metals for food safety over the past five years, according to fluorophores and newly emerging sensing cores, which could contribute to broadening the prospects of fluorescent materials and establishing more practical assays for heavy metal determinations.

Colorimetric detection of Hg2+ with an azulene-containing chemodosimeter via dithioacetal hydrolysis

Azulene is a bicyclic aromatic chromophore that absorbs in the visible region. Its absorption maximum undergoes a hypsochromic shift if a conjugated electron-withdrawing group is introduced at the C1 position. This fact can be exploited in the design of a colorimetric chemodosimeter that functions by the transformation of a dithioacetal to the corresponding aldehyde upon exposure to Hg2+ ions. This chemodosimeter exhibits good chemoselectivity over other metal cations, and responds with an unambiguous colour change clearly visible to the naked eye. Its synthesis is concise and its ease of use makes it appropriate in resource-constrained environments, for example in determing mercury content of drinking water sources in the developing world.

Recent Progress in Small-Molecule Fluorescent Probes for Detecting Mercury Ions

Mercury is a highly toxic and non-essential element that is found in every corner of the globe. The small amount of mercury produced by various pathways eventually enters freshwater and marine ecosystems, circulating through the food chain (especially fish) and causing various environmental problems in aspects including plants, animals, and human. There are several traditional quantitative methods developed for mercury ions (II) analysis in water samples. However, due to the complexity of the detection process, high cost and strong technical expertise, it is difficult to detect mercury ions in real-time. Therefore, in recent years, a large number of researchers have developed small-molecule fluorescent probes for Hg ions detection. Fluorimetry has the advantages of convenient detection, short response time, high sensitivity and good selectivity. This review summarized the small-molecule fluorescent probes for mercuric ion detection developed in recent years according to the chemical structural classification, compared their performances and elaborated the mechanism. We hope that the review will help the researches for the designs of metal ions fluorescent probes and their applications with certain reference value.

A New Fluorescent Turn-on Dual Interaction Position Probe for Determination of Hydrazine

Hydrazine is an important catalyst and chemical raw material. But it is highly toxic and potentially carcinogenic. We designed a new hydrazine probe based on a synergistic effect by introducing acetate and phthalimide into 2-phenyl-benzimidazole (PBI). Comparative experiments proved that "the dual position interaction" had a "synergistic effect" on fluorescence enhancement. The fluorescence enhancement caused by the probe (15.0 fold) is much larger than the sum of the fluorescence enhancement of the two monomer compounds (2.6 and 1.4 folds, respectively). A theoretical calculation showed an inhibition of the PET process and a recovery of the ICT process led to a fluorescence enhancement. The probe was specific to hydrazine and showed a linear response to it in the concentrations range of 0.2 - 200 μM with a LOD of 0.062 μM (1.99 ppb). Moreover, the probe could detect hydrazine in tap water; the recovery of hydrazine from the tap water was between 98.86 - 103.28%.

A Near-infrared Fluorescent Probe of Dicyanoisophorone Derivatives for Selective Detection and Fluorescence Cellular Imaging of Palladium

Palladium (Pd) has been acknowledged to be a rare inner transition metal, which plays a pivotal role in many fields. This article focuses on developing a safe and effective near-infrared fluorescent probe, MW-PD, which would make a great contribution to the detection of palladium residue in drugs, especially trace residues. The fluorescent probe was rationally designed by combining the dicyanoisophorone fluorophore with an allyloxycarbonyl group. Based on the Tsuji-Trost reaction, the probe exhibited high selectivity and sensitivity toward Pd (0) over other common metal ions with a low detection limit (8.0 nM). Moreover, MW-PD showed biocompatibility and was successfully applied to imaging Pd (0) in Hela cells.

Simply Structured Conjugated Compounds with Cyanoacrylate or Acrylonitrile Groups for Sensing of p-Toluenethiol

Simply structured conjugated compounds with cyanoacrylate (CA 1 - 4) and acrylonitrile (AN 1 - 4) terminal groups were synthesized by a Knoevenagel condensation reaction in one step and investigated for their recognition properties to p-toluenethiol by UV-vis, fluorescence spectra, and FT-IR measurements. When p-toluenethiol was added to CA 1, the FT-IR spectra revealed a cleavage of alkene caused by the addition reaction between p-toluenethiol and CA 1. An increase in p-toluenethiol concentration, a blue-shifted absorption band, and a decrease in the fluorescence intensity of CA 1 were observed because of the decrease in its effective conjugated length. Therefore, the most simply structured CA 1 was found to be the most effective and the most sensitive chemical sensor for p-toluenethiol.