A novel colorimetric chemosensor for Cu2+ with high selectivity and sensitivity based on Rhodamine B

Rhodamine-Anchored Polyacrylamide Hydrogel for Fluorescent Naked-Eye Sensing of Fe3

A fluorescent and colorimetric poly (acrylamide)-based copolymer probe P(AAm-co-RBNCH) has been designed via free radical polymerization of a commercial acrylamide monomer with a rhodamine-functionalized monomer RBNCH. Metal ion selectivity of RBNCH was investigated by fluorescence and colorimetric spectrophotometry. Upon addition of Fe3+, a visual color change from colorless to red and a large fluorescence enhancement were observed for the ring-opening of the rhodamine spirolactam mechanism. The monomer gives a sensitive method for quantitatively detecting Fe3+ in the linear range of 100-200 μM, with a limit of detection as low as 27 nM and exhibiting high selectivity for Fe3+ over 12 other metal ions. The hydrogel sensor was characterized by FTIR, and the effects of RBNCH amount on gel content and swelling properties were explored. According to the recipe of 1.0 mol% RBNCH to the total monomers, the fabricated hydrogel sensor displayed a good swelling property and reversibility performance and has potential for application in the imaging of Fe3+ level in industrial wastewater.

Research Progress on Up-Conversion Fluorescence Probe for Detection of Perfluorooctanoic Acid in Water Treatment

Perfluorooctanoic acid (PFOA) is a new type of organic pollutant in wastewater that is persistent, toxic, and accumulates in living organisms. The development of rapid and sensitive analytical methods to detect PFOA in environmental media is of great importance. Fluorescence detection has the advantages of high efficiency and low cost, in which fluorescent probes have excellent fluorescence properties, excellent bio-solubility, and remarkable photostability. It is necessary to review the fluorescence detection routes for PFOA. In addition, the up-conversion of fluorescent materials (UCNPs), as fluorescent materials to prepare fluorescent probes with, has significant advantages and also attracts the attention of researchers, however, reviews related to their application in detecting PFOA and comparing them with other routes are rare. Furthermore, there are many strategies to improve the performance of up-conversion fluorescent probes including SiO₂ modification and amino modification. These strategies can enhance the detection effect of PFOA. Thus, this work reviews the types of fluorescence detection, the design, and synthesis of UCNPs, their recognition mechanism, properties, and their application progress. Moreover, the development trend and prospects of these detection probes are given.

Microwave-assisted synthesis for a highly selective rhodamine 6G-derived fluorescent sensor and bioimaging

A new rhodamine 6G derivative R1 has been synthesized by condensation of rhodamine hydrazide and 6-hydroxymethyl-pyridine using microwave-assisted reaction. Naked-eye colorimetric and photo physical studies show the synthesized compound is selectively sensing Cu2+ in CH3CN/H2O (9:1, v/v) solution. Upon coordination with Cu2+ ion, the spirolactam of R1 is opened, which results in a formation of highly fluorescent complex and change in color of the solution. The Job's plot indicates 1:2 binding stoichiometry between Cu2+ ion and R1. Limit of detection for Cu2+ was determined to be 1.23 μM. The sensor was successfully applied to fluorescent imaging of Cu2+ ion in living cells.

A New bis(rhodamine)-Based Colorimetric Chemosensor for Cu2

A novel sensor (RD) bearing rhodamine B and 4-tert-Butyl phenol unit have been designed and synthesized using microwave irradiation. The sensor allows selective detection of Cu2+ by forming absorptive complex and trigger the formation of highly colored ring-open spirolactam. The recognition ability of the sensor was investigated by absorbance, Job's plot, infrared (IR) and time dependent-density functional theory (TD-DFT) calculations.

A novel hexahydroquinazolin-2-amine-based fluorescence sensor for Cu2+ from isolongifolanone and its biological applications

The isolongifolanone derivative (2c) exhibit highly selective and sensitive fluorescence quenching towards copper ions, and this was used for real-time sensing of cooper ions in vivo.