Rapid and visual detection of folic acid via supramolecular recognition with a perylene bisimide probe in aqueous media

A Highly Sensitive and Selective Fluorescent Sensor for Folic Acid Detection Based on D-penicillamine Stabilized Ag/Cu Alloy Nanoclusters

In this work, a highly sensitive and selective method for detecting folic acid (FA) was developed using D-penicillamine (DPA) stabilized Ag/Cu alloy nanoclusters (DPA@Ag/Cu NCs). The yellow emission of DPA@Ag/Cu NCs was found to be quenched upon the addition of FA to the system. The fluorescence intensity quenching value demonstrated a linear relationship with FA concentrations ranging from 0.01 to 1200 μM, with a limit of detection (LOD) of 5.3 nM. Furthermore, the detection mechanism was investigated through various characterization analyses, including high resolution transmission electron microscopy, fluorescence spectra, ultraviolet-visible absorption spectra, and fluorescence lifetime. The results indicated that the fluorescence quenching induced by FA was a result of electron transfer from FA to the ligands of DPA@Ag/Cu NCs. The selectivity of the FA sensor was also evaluated, showing that common amino acids and inorganic ions had minimal impact on the detection of FA. Moreover, the standard addition method was successfully applied to detect FA in human serum, chewable tablets and FA tablets with promising results. The use of DPA@Ag/Cu NCs demonstrates significant potential for detecting FA in complex biological samples.

In Situ Generated Dye@MOF/COF Heterostructure for Fluorescence Detection of Chloroquine Phosphate and Folic Acid via Different Luminescent Channels

Metal-organic framework (MOF) and covalent-organic framework (COF) hybrid materials can combine the unique properties of MOF and COF components, and their applications in fluorescence sensing have attracted more and more attention. Herein, ZIF-90 is grown on 3D-COF by a simple in situ growing method in which the 7-amino-4-methylcoumarin (AMC) is encapsulated in ZIF-90 to construct a fluorescent sensor. Chloroquine phosphate (CQP) can coordinate with Zn2+ to decompose the ZIF-90 and release AMC. At 365 nm excitation, the ratiometric fluorescence signal AMC/3D-COF (I430/I598) increases linearly with CQP in a linear range of 4 × 10-5 to 4 × 10-4 M in urine. Under 340 nm excitation, quantitative analysis of CQP in the serum (3 × 10-6 to 4 × 10-5 M) is based on the fluorescence intensity of Zn-CQP/3D-COF (I384/I598). In addition, AMC@ZIF-90/3D-COF (1) exhibits high anti-interference and selectivity in sensing of FA with a "turn off" mode, with a correlation range of 1 × 10-5 to 1 × 10-3 M. The fluorescence color changes triggered by CQP under different excitation conditions, and the different fluorescence responses caused by CQP make it a highly secure anticounterfeiting platform. The synthesized dye@MOF/COF hybrids not only provide a new way to integrate multiple emission to design fluorescent probes for differentiation detection but also offer ideas for the design of anticounterfeiting platforms.

Rapid detection of hydrogen sulfide in vegetables and monosodium glutamate based on perylene supramolecular aggregates using an indicator displacement assays strategy

Hydrogen sulfide (H₂S) has been clearly identified as a hazardous chemical pollutant that seriously affects food safety and human health. In order to develop a rapid, accurate and efficient H₂S tracking method, this work propose a strategy based on indicator displacement assays (IDA). A water-soluble histidine-modified perylene diimide fluorescent probe was synthesized by a one-step method, and the probe can form supramolecular aggregates in the presence of Cd²⁺. There will be a fluorescence transformation of probe, caused by the change of the state of aggregation and adjusted by various concentration of S^2-, which can achieve the fluorescence detection of S^2-. The limit of detection is as low as 0.41 µmol/L. Particularly worth mentioning is that the probe in this work can be recycled for at least 5 times, which is environmentally friendly and economical. Finally, this method was applied in three kinds of vegetables and monosodium glutamate samples.

Rapid and sensitive detection of dextran sulfate sodium based on supramolecular self-assembly of a perylene diimide derivative in aqueous solution

Dextran sulfate sodium (DSS) is a heparin polysaccharide, whose overuse would cause many adverse effects, such as stiff and painful joints and loss of hair. It is crucial to search after a rapid and accurate approach for the determination of DSS in the clinical treatment and diagnosis. Regrettably, there are few literatures about analytical methods for detecting DSS at present. In this research, a sensitive and selective method for detecting DSS based on the hydrosoluble perylene diimide (PDI) derivative was established in pure aqueous solution. The sensing mechanism and performance of PDI-PdEC were systematically investigated by ultraviolet and fluorescence spectroscopy. Non-covalent interactions between DSS and PDI-PdEC, like π-π stacking, electrostatic and hydrophobic interaction, promote the aggregation of PDI-PdEC and form supramolecular aggregates, which realize the sensitive and rapid detection of DSS in aqueous system. The detection limit for DSS is as low as 5.51 ng/mL and the linear range is 20-500 ng/mL. Furthermore, this probe was triumphantly applied in the detecting of DSS in serum. To the best of our knowledge, this is the first fluorescent probe for detecting DSS in aqueous media. We consider that our study will not only broaden the range of applications of perylene diimide fluorescent sensors, but also provide valuable reference for the design of new sensors for the rapid determination method of DSS.

Polyaniline spinel particles with ultrahigh-performance liquid chromatography tandem mass spectrometry for rapid vitamin B9 determination in rice

Rice is an important crop that provides energy and nutrients to humans, which undergoes the aging process, the quality decline is related to the exogenous storage conditions and the change of own enzyme activity. However, due to the complex composition of rice and serious matrix interference, the ageing identification of rice is still challenging. Hence, a novel spinel particles ZnFe₂O₄@PANI was designed and synthesized for adsorption and determination of vitamin B₉, which can be used to distinguish rice in different years and analyze the degree of aging. The ZnFe₂O₄@PANI showed large specific surface area and fast mass transfer rate with good linear correlation coefficient (R² = 0.9965), satisfactory recoveries (85.1%-99.9%) and relative standard deviations (RSD, 9.3%). Moreover, the π-π electron-donor-acceptor (EDA) and intermolecular hydrogen-bonding interactions of polyaniline coating provided selective adsorption on vitamin B₉. Adsorption thermodynamics study suggested that the adsorption reactions were spontaneous, endothermic and thermodynamically favorable. Finally, ZnFe₂O₄@PANI was used to evaluate vitamin B₉ in rice from different years, which laid a theoretical foundation for exploring the relationship between vitamin changes and the aging degree of the rice.

A red luminescent europium metal organic framework (Eu-MOF) integrated with a paper strip using smartphone visual detection for determination of folic acid in pharmaceutical formulations

Integration of smartphone with visual-based paper strip as a low-cost, fast, and reliable probe for semi-quantitative analysis of folic acid.