A Natural Light Visible Colorimetric Responses Fluorescent Probe for Hydrazine Detection

Synthesis and Application of Specific N2H4 Fluorescent Probes with AIE Effect Based on Pyrazole Structure

Two fluorescent probes, Y1-2 were synthesized from 2-acetonaphthone, 4-acetylbiphenyl, and phenyl hydrazine by Vilsmeier-Haack reaction and Knoevenagel condensation. Their recognition efficacies for N2H4 were tested by UV-visible absorption spectroscopy and fluorescence emission spectroscopy. The recognition mechanism were studies by density-functional theory calculations, and the effect of pH on N2H4 recognition was also studied. The results showed that the probe Y1-2 has high selectivity and a low detection limit for N2H4, and the recognition of N2H4 can be accomplished at physiological pH. The probes have had obvious aggregation-induced luminescence effect, large Stokes shift, high sensitivity, and can be successfully applied to live cell imaging.

A colorimetric probe for the detection of hydrazine and its application

A colorimetric probe was developed to detect N2H4 content based on the colour change in natural light, and the recognition mechanism is the N2H4 cutting the ester bond of probe 1. As the N2H4 concentration increases, the Ultraviolet absorption ratio (A352nm/A505nm) of the probe solution was gradually increases, and the colour of the solution changed from colourless to pink under natural light. The detection limit of probe 1 for N2H4 was 0.1 μM. The probe can also be applied to test paper detection, and the test paper of probe was changed from colourless to fluorescent yellow under UV light as the concentration of N2H4 increased. There was a linear functional relationship between the RGB (Red, Green, Blue) values of the photos and the N2H4 concentration. Probe 1 is a rapid detection tool for N2H4 concentration using a smartphone. Furthermore, the probe can also be used to detect N2H4 in tap water, tea and apple juice.

Two Ratiometric Fluorescent Probes Based on the Hydroxyl Coumarin Chalcone Unit with Large Fluorescent Peak Shift for the Detection of Hydrazine in Living Cells

Hydrazine is widely used in industrial and agricultural production, but excessive hydrazine possesses a serious threat to human health and environment. Here two new ratiometric fluorescence probes, DDP and DDC, with the hydroxyl coumarin chalcone unit as the sensing site are developed, which can achieve colorimetric and ratiometric recognition for hydrazine with good sensitivity, excellent selectivity, and anti-interference. The calculated fluorescence limits of detections are 0.26 μM (DDC) and 0.14 μM (DDP). The ratiometric fluorescence response to hydrazine is realized through the adjustment of donor and receptor units in coumarin conjugate structure terminals, accompanied by fluorescence peak shift about 200 nm (DDC, 188 nm; DDP, 229 nm). Stronger electropositivity in the carbon-carbon double bond is helpful to the first phase addition reaction between the probe and hydrazine. Higher phenol activity in the hydroxyl coumarin moiety will facilitate the following dihydro-pyrazole cyclization reaction. In addition, both of these probes realized the convenient detection of hydrazine vapor. The probes were also successfully applied to detect hydrazine in actual water samples, different soils, and living cells.

A dual-mode visual detector for toxic hydrazine

Hydrazine (N₂H₄) is one of the commonly used chemical reagents in numerous industries and applications but its toxicity to humans poses a need to develop simple visual detection methods. Herein, we demonstrate a novel dual-mode system to detect and simultaneously consume hydrazine in vapour and solution by using a small photoresponsive molecule that has altered optical response (both colourimetric and fluorescent) after reacting with hydrazine.

A small photoresponsive molecule changes colour from blue to colourless when exposed to hydrazine vapours. It also becomes emissive providing two convenient ways of detecting the presence of this toxic chemical.

The recent advance of organic fluorescent probe rapid detection for common substances in beverages

The beverage industry is confronted with tremendous challenges in terms of quality assurance. The allowed contents of common ingredients such as copper ions, hydrogen sulfide, cysteine and caffeine are stipulated by various governing bodies, and the beverage industry must ensure that it meets these requirements. Due to its unique advantages of high sensitivity, low cost and relatively low toxicity over high-performance liquid chromatography, atomic absorption spectrometry and nanomaterials, the use of organic fluorescent probes for the rapid detection of beverage contents has become a hot research topic. This review summarizes the detection of common substances in wine, tea, mineral water, milk and other beverages. Furthermore, the preparation of test paper and simple colour comparison are discussed to display the rapid qualitative capability of designed probes. To improve the current state of beverage safety, future trends and strategies for fast organic fluorescent probe detection in the beverage industry are also discussed.

Hydrazine exposure: A near-infrared ICT-based fluorescent probe and its application in bioimaging and sewage analysis

Hydrazine (N₂H₄) is an environment pollutant with high acute toxicity and potential carcinogenicity, and detection of N₂H₄ has attracted increasing attention. In the present study, a low toxicity near-infrared fluorescent probe (DCDB) based on the intramolecular charge transfer (ICT) principle was developed. The probe DCDB exhibits excellent selectivity and high sensitivity (LOD = 1.27 ppb) for N₂H₄, fast reaction rate (5 min), extremely large Stokes shift (160 nm). The color transformation of the DCDB-N₂H₄ system from purple to pink can be observed with the naked eye. The success of N₂H₄ test strips to detect trace N₂H₄ in actual sewage strongly illustrates the practical application potential of DCDB. Importantly, DCDB can be utilized to monitor the distribution of exogenous N₂H₄ in vivo and in vitro.

The preparation of a special fluorescent probe with an aggregation-induced emission effect for detecting hydrazine in water

A novel phenyl-carbazole fluorescent molecule, PCBI, with an AIE effect is used as an excellent special probe for the detection of N2H4 in a DMF–H2O system.