Pyridine Ionic Liquid Functionalized MOF-5 Coupled with High-Performance Liquid Chromatography for Analysis of Allura Red in Food Samples

Electrochemical luminescence sensor for the detection of Allure Red: double luminescence cooperative amplification strategy of self-supporting material Zn3Cu2O2 and CdTe@MWNTs

The self-supporting material Zn3Cu2O2 was synthesized through the methods of electrospinning combined with high-temperature calcination. A novel sensitive electrochemiluminescence (ECL) sensor based on Zn3Cu2O2 and CdTe@MWNTs was constructed by the multi-step amplification strategy. First, Zn3Cu2O2 and CdTe served as the ECL groups to construct the sensor, yielding a larger signal of the sensor in the presence of the co-reactant K2S2O8. Multi-walled carbon nanotubes (MWNTs) were introduced as a carrier to increase the signal value of the sensor further. The synergistic action of CdTe@MWNTs and Zn3Cu2O2 made the system obtain the maximum initial signal. With the addition of Allure Red (AR), the ECL signal decreased. The quenching phenomenon was not only due to the large organic molecule AR occupying the active sites of Zn3Cu2O2 and CdTe, but also, more importantly, because the sensor existed as an ECL-RET mechanism between CdTe and AR. The response mechanism and experimental conditions of the system were also investigated. Under optimal conditions, the sensor showed a linear relationship between the ECL signal change and the logarithm of AR concentration in the range 1.0 × 10-14 to 1.0 × 10-6 mol L-1, the linear equation was ∆I = 15,295.54 + 956.42 log CAR, and the correlation coefficient was 0.9928. The lowest detection limit of (S/N = 3) was 1.67 × 10-15 mol L-1. Satisfactory results were obtained for the analysis  of beverages.

Recent Progress and Applications of Advanced Nanomaterials in Solid-Phase Extraction

Sample preparation maintains a key bottleneck in the whole analytical procedure. Solid-phase sorbents (SPSs) have garnered increasing attention in sample preparation research due to their crucial roles in achieving high clean-up and enrichment efficiency in the analysis of trace targets present in complex matrices. Novel nanoscale materials with improved characteristics have garnered considerable interest across different scientific disciplines due to the limited capabilities of traditional bulk-scale materials. The purpose of this review is to offer a thorough summary of the latest developments and uses of SPSs in preparing samples for chromatographic analysis, focusing on the years 2020-2024. The techniques for preparing SPSs are examined, such as metal-organic frameworks (MOFs), covalent organic frameworks (COFs), carbon nanoparticles (CNPs), molecularly imprinted polymers (MIPs), and metallic nanomaterials (MNs). Examining the pros and cons of different extraction methods, including solid-phase extraction (SPE), magnetic SPE (MSPE), flow-based SPE (FBA-SPE), solid-phase microextraction (SPME), stir-bar sorptive extraction (SBSE), and dispersive SPE (DSPE), is the main focus. Furthermore, this article presents the utilization of SPE technology for isolating common contaminants in various environmental, biological, and food specimens. We highlight the persistent challenges in SPSs and anticipate future advancements and applications of novel SPSs.

An ultrasound assisted dispersive micro solid-phase extraction and a composite ionic liquid-metal organic framework for sixteen polycyclic aromatic hydrocarbons analysis in fruit juice and environmental water samples

Aluminum-based metal organic framework composite containing ionic liquid was prepared and used as sorbent for extraction of sixteen polycyclic aromatic hydrocarbons in list of priority pollutants of United States Environmental Protection Agency before their analysis by gas chromatography/mass spectrometry. The dispersive micro solid-phase extraction method, known as a simple and fast method, was preferred as the extraction method. The optimized parameter conditions were 5 mL of sample solution, 10 min sonication by ultrasonic bath, 30 mg of sorbent, 30 °C extraction temperature, 0.1 mL of hexane as elution solvent with 5 min elution time. The suggested method presented that limit of detection and limit of quantification were in the range of 0.01-0.10 μg l-1, and 0.04-0.33 μg L-1, respectively. The intra-day and inter-day repeatability were within the ranges of 1.18-4.88 % and 1.02-5.06 %, respectively. The recoveries for polycyclic aromatic hydrocarbons in peach juice, cherry juice, tap water and rain water samples were obtained in the range of 84.9-99.9 % for spiked 5, 50 and 100 μg l-1 standard polycyclic aromatic hydrocarbons solution.

Ionic Liquids Functionalized MOFs for Adsorption

Metal-organic frameworks (MOFs) and ionic liquids (ILs) represent promising materials for adsorption separation. ILs incorporated into MOF materials (denoted as IL/MOF composites) have been developed, and IL/MOF composites combine the advantages of MOFs and ILs to achieve enhanced performance in the adsorption-based separation of fluid mixtures. The designed different ILs are introduced into the various MOFs to tailor their functional properties, which affect the optimal adsorptive separation performance. In this Perspective, the rational fabrication of IL/MOF composites is presented, and their functional properties are demonstrated. This paper provides a critical overview of an emergent class of materials termed IL/MOF composites as well as the recent advances in the applications of IL/MOF composites as adsorbents or membranes in fluid separation. Furthermore, the applications of IL/MOF in adsorptive gas separations (CO2 capture from flue gas, natural gas purification, separation of acetylene and ethylene, indoor pollutants removal) and liquid separations (separation of bioactive components, organic-contaminant removal, adsorptive desulfurization, radionuclide removal) are discussed. Finally, the existing challenges of IL/MOF are highlighted, and an appropriate design strategy direction for the effective exploration of new IL/MOF adsorptive materials is proposed.