Ultrasensitive electrochemiluminescence determination of trace Ag ions based on the signal amplification caused by its catalytic effect on Mn(II) oxidation using graphite catheter as electrode

Ratiometric electrochemiluminescence sensing and intracellular imaging of ClO- via resonance energy transfer

Electrochemiluminescence resonance energy transfer (ECL-RET) is a versatile signal transduction strategy widely used in the fabrication of chem/biosensors. However, this technique has not yet been applied in visualized imaging analysis of intracellular species due to the insulating nature of the cell membrane. Here, we construct a ratiometric ECL-RET analytical method for hypochlorite ions (ClO-) by ECL luminophore, with a luminol derivative (L-012) as the donor and a fluorescence probe (fluorescein hydrazide) as the acceptor. L-012 can emit a strong blue ECL signal and fluorescein hydrazide has negligible absorbance and fluorescence signal in the absence of ClO-. Thus, the ECL-RET process is turned off at this time. In the presence of ClO-, however, the closed-loop hydrazide structure in fluorescein hydrazide is opened via specific recognition with ClO-, accompanied with intensified absorbance and fluorescence signal. Thanks to the spectral overlap between the ECL spectrum of L-012 and the absorption spectrum of fluorescein, the ECL-RET effect is gradually recovered with the addition of ClO-. Furthermore, the ECL-RET system has been successfully applied to image intracellular ClO-. Although the insulating nature of the cell itself can generate a shadow ECL pattern in the cellular region, extracellular ECL emission penetrates the cell membrane and excites intracellular fluorescein generated by the reactions between fluorescein hydrazide and ClO-. The cell imaging strategy via ECL-RET circumvents the blocking of the cell membrane and enables assays of intracellular species. The importance of the ECL-RET platform lies in calibrating the fluctuation from the external environment and improving the selectivity by using fluorescent probes. Therefore, this ratiometric ECL sensor has shown broad application prospects in the identification of targets in clinical diagnosis and environmental monitoring.

An Ethyl-Thioglycolate-Functionalized Fe3O4@ZnS Magnetic Fluorescent Nanoprobe for the Detection of Ag+ and Its Applications in Real Water Solutions

Ethyl-thioglycolate-modified Fe₃O₄@ZnS nanoparticles (Fe₃O₄@ZnS-SH) were successfully prepared using a simple chemical precipitation method. The introduction of ethyl thioglycolate better regulated the surface distribution of ZnS, which can act as a recognition group and can cause a considerable quenching of the fluorescence intensity of the magnetic fluorescent nanoprobe, Fe₃O₄@ZnS-SH. Benefiting from stable fluorescence emission, the magnetic fluorescent nanoprobe showed a highly selective fluorescent response to Ag+ in the range of 0-400 μM, with a low detection limit of 0.20 μM. The magnetic fluorescent nanoprobe was used to determine the content of Ag⁺ in real samples. A simple and environmentally friendly approach was proposed to simultaneously achieve the enrichment, detection, and separation of Ag⁺ and the magnetic fluorescent nanoprobe from an aqueous solution. These results may lead to a wider range of application prospects of Fe₃O₄ nanomaterials as base materials for fluorescence detection in the environment.

Recent progress in electrochemiluminescence microscopy analysis of single cells

An overview of recent progress in electrochemiluminescence microscopy analysis of single cells classified according to different ECL routes, namely the oxidative-reduction, low oxidation potential, catalytic and direct oxidation routes.

Green choline amino acid ionic liquids aqueous two-phase extraction coupled with synchronous fluorescence spectroscopy for analysis naphthalene and pyrene in water samples

A novel aqueous two-phase extraction method has been established for the determination of polycyclic aromatic hydrocarbons in water sample. This method was based on the extraction of naphthalene and pyrene from water by means of choline amino acid ionic liquids aqueous two-phase system and their determination by synchronous fluorescence spectroscopy. In synchronous fluorescence spectroscopy, the fluorescence peaks of naphthalene and pyrene were completely separated to meet the requirement of simultaneous determination. For this method, good linear calibration curves of naphthalene and pyrene were obtained in the range of 0.50-10.0, 0.05-5.0 μg mL^-1, respectively, and limits of detection were 0.211, 0.012 μg mL^-1, respectively. The proposed method was successfully applied for the simultaneous determination of naphthalene and pyrene in water samples, which was considered as an excellent green analysis according Analytical Eco-Scale.