Bimetallic porous Mn/Co oxide nanosheets with efficient oxidase-mimicking activity for the sensitive colorimetric determination of resveratrol in different matrices.

BACKGROUND: Resveratrol, a natural polyphenol compound used as an ingredient in dietary supplements, and pharmaceuticals, has gained significant attention due to its potential health benefits. However, the accurate and sensitive determination of resveratrol in complex matrices remains a challenge. In this study, we propose the utilization of bimetallic porous Mn/Co oxide nanosheets (MnCoO-NSs) as catalysts for the colorimetric determination of resveratrol. RESULTS: The bimetallic porous MnCoO-NSs were prepared through a facile one-stone-two-birds strategy. These nanosheets exhibited superior oxidase-mimicking activity, as evidenced by the catalytic oxidation of the chromogenic substrate 3,3',5,5'-tetramethylbenzidine (TMB), producing a blue-colored oxTMB species with a prominent absorbance peak at 655 nm. The catalytic activity was promoted through the production of superoxide anion (O2•-), which enhanced the affinity of MnCoO-NSs to the TMB molecules. Upon the addition of resveratrol, the oxidation process was inhibited, resulting in rapid fading of the blue color. This colorimetric sensing platform exhibited a linear response to resveratrol concentrations over the range of 2.2-87.6 µM, with a limit of detection of 0.210 µM. The method was further applied for the determination of resveratrol in different matrices including biological fluids, pharmaceuticals, and environmental water. SIGNIFICANCE: The utilization of these MnCoO-NSs offers a simple and cost-effective alternative to conventional analytical techniques for the determination of resveratrol. Their high sensitivity, selectivity, and stability enable accurate measurements of resveratrol in various complex matrices. This research has implications in areas such as pharmaceutical analysis, biomedical research, and environmental analysis, where the reliable determination of resveratrol is crucial for assessing its therapeutic potential and ensuring product quality.

Applications of deep eutectic solvents in microextraction and chromatographic separation techniques: Latest developments, challenges, and prospects.

Deep eutectic solvents (DESs) have recently sparked considerable attention in a variety of scientific and technological fields. The unique properties of DESs include biodegradability, easy preparation, low cost, and tuneability, rendering them a new and prospective alternative to hazardous solvents. Analytical chemistry is one of the most appealing fields where DESs proved to be applicable in either sample preparation or chromatographic separation. This review summarizes the new horizons dedicated to the application of DESs in microextraction and chromatographic separation. The utilization of DESs in microextraction, in chromatography as mobile phase additives, and in chromatographic material preparation processes is outlined. The enhancements in chromatographic performance achieved using DESs and any potential explanations deduced from the experimental findings were primarily discussed. An additional brief discussion on DESs preparation, characterization, and properties is addressed in this work. Finally, current challenges and future trends are also presented, supplying evidence for distinct possibilities regarding new research approaches involving DESs. This review can represent a guide and stimulate further research in this field.

Simple and affordable synchronous spectrofluorimetric determination of the natural anticancer polyphenols; resveratrol and curcumin in human plasma.

In this work, resveratrol and curcumin, two natural polyphenols, were simultaneously determined in human plasma samples using a rapid, sensitive, green, and affordable synchronous fluorescence spectroscopic approach. Several factors affecting the performance of the procedure, including Δλ, pH, diluting solvent, and organized medium, were optimized. Based on the findings, the fluorescence of resveratrol and curcumin was measured at 304 and 443 nm, respectively, with Δλ of 80.0 nm and ethanol as the diluting solvent. Excellent linearity was demonstrated by the approach (r = 0.9999) over the concentration range of 5.00-1000.00 and 2.00-400.00 ng/mL for resveratrol and curcumin, respectively. The obtained detection limits for resveratrol and curcumin were 0.027 and 0.042 ng/mL, respectively, indicating the high sensitivity of the proposed method. Moreover, the method exhibited excellent precision (both inter and intra-day), with %RSD < 1 %. The "green analytical process index" and "Analytical GREEnness" metric tools were used to compare the green profiles of the proposed method to those of the published methods. These two greenness evaluation tools verified that the suggested methodology satisfied the greatest number of green criteria, proposing its usage as a green alternative for the routine analysis of the investigated natural anticancer polyphenols in human plasma.

Modified µ-QuEChERS coupled to diethyl carbonate-based liquid microextraction for PAHs determination in coffee, tea, and water prior to GC-MS analysis: An insight to reducing the impact of caffeine on the GC-MS measurement.

A fast, sensitive and eco-friendly method was developed for the determination of fifteen polycyclic aromatic hydrocarbons (PAHs) in different environmental matrices through gas chromatography mass spectrometry (GC-MS). The method utilizes a modified and miniaturized quick easy cheap effective rugged and safe (QuEChERS) clean up procedure coupled to an air-assisted dispersive liquid-liquid microextraction (AA-DLLME) for the enrichment of the concerned compounds. The AA-DLLME uses diethyl carbonate (DEC) as a green bio-based solvent for the microextraction. DEC is considered as biodegradable (with octanol/water coefficient < 3, resulting in low potential of bioaccumulation), classified as a green solvent and considered as one of the recommended solvent alternatives based on SSG results. The AA-DLLME procedure was optimized by One-Variable-at-A-Time (OVAT) succeeded by experimental design applying Central Composite Face-centered (CCF) design. The method linear calibration was found in the range of 10-120 µg/Kg for Benzo[a]pyrene and 5-100 µg/Kg for all other PAHs with low detection limits ranging from 0.01 to 2.10 µg/Kg. It could enrich the PAHs up to 166-folds. The combination of modified µ-QuEChERS with the green AA-DLLME could sharply decrease the caffeine amount on the final extract injected to the GC-MS instrument. The method was successfully applied to coffee, tea, and water samples with acceptable % recovery (>90%). Finally, the impact of our procedure to the environment from green analytical chemistry view was assessed by a novel metric system called AGREE, proving the greenness of our procedure.