Separation and Detection of Catechins and Epicatechins in Shanxi Aged Vinegar Using Solid-Phase Extraction and Hydrophobic Deep Eutectic Solvents Combined with HPLC.

This research presents a new, eco-friendly, and swift method combining solid-phase extraction and hydrophobic deep eutectic solvents (DES) with high-performance liquid chromatography (SPE-DES-HPLC) for extracting and quantifying catechin and epicatechin in Shanxi aged vinegar (SAV). The parameters, such as the elution solvent type, the XAD-2 macroporous resin dosage, the DES ratio, the DES volume, the adsorption time, and the desorption time, were optimized via a one-way experiment. A central composite design using the Box-Behnken methodology was employed to investigate the effects of various factors, including 17 experimental runs and the construction of three-dimensional response surface plots to identify the optimal conditions. The results show that the optimal conditions were an HDES (tetraethylammonium chloride and octanoic acid) ratio of 1:3, an XAD-2 macroporous resin dosage of 188 mg, and an adsorption time of 11 min. Under these optimal conditions, the coefficients of determination of the method were greater than or equal to 0.9917, the precision was less than 5%, and the recoveries ranged from 98.8% to 118.8%. The environmentally friendly nature of the analytical process and sample preparation was assessed via the Analytical Eco-Scale and AGREE, demonstrating that this method is a practical and eco-friendly alternative to conventional determination techniques. In summary, this innovative approach offers a solid foundation for the assessment of flavanol compounds present in SAV samples.

A simple gelatin aerogel tablet sorbent for the effective vortex assisted solid phase extraction of polycyclic aromatic hydrocarbons from tea samples.

A gelatin aerogel tablet was used as a vortex assisted solid phase extraction (VA-SPE) sorbent for the determination of polycyclic aromatic hydrocarbons (PAHs), benzo(a)anthracene (BaA), benzo(b)fluoranthene (BbF), and benzo(a)pyrene (BaP) in tea samples. They have been quantified by a high-performance liquid chromatography with a diode array detector (HPLC-DAD). The method shows good linearity (R2 = 0.999) at concentrations of 5.00-200 ng L-1, with the limits of detection of 1.65 ± 0.02, 1.81 ± 0.02, and 2.06 ± 0.03 ng L-1 for BaA, BbF, and BaP, respectively. Good reproducibility (RSDs < 0.24%, n = 6), good precision (RSDs < 6.3%), and excellent reusability (n = 40, RSDs < 0.17%) were achieved. The tablet can extract PAHs within 1.5 min with good recoveries (70.10 ± 0.74% - 119.3 ± 4.1%). This method, which is simple, rapid, ecofriendly, and inexpensive, requires low consumption of organic solvent, and has potential application in food safety.

One-step fabrication of hydrophilic MIL-68(Al)/Chitosan-coated melamine sponge for vortex-assisted solid-phase extraction of parabens in water samples.

A novel vortex-assisted solid-phase extraction method based on MIL-68(Al)/Chitosan-melamine sponge column (or V-MIL-68(Al)/CS-SC-SPE) is presented in this paper. The MIL-68(Al)/Chitosan-sponge column was prepared by a simple infiltration method and a preparation process that does not consume organic solvents. Scanning electron microscopy was used to characterize the functionalized sponge columns, and the skeleton and pores of the melamine sponge were successfully modified with the coating material (MIL-68(Al) and chitosan). Chitosan was used successfully not only as an adsorption adjuvant material, but also as an adhesive in the preparation of MIL-68(Al)/CS coating sponge materials. The presented method was further combined with high performance liquid chromatography (HPLC) and used in the determination of trace parabens (including methyl-, ethyl-, propyl- and butyl-parabens) in environmental water samples. Several important factors that affect the extraction performance were investigated. Under the optimum conditions, the method was successfully used to detect the four kinds of parabens in different water samples (domestic water, lake water and river water). The limits of detection ranged between 0.21 and 0.50 ng/mL, and the relative standard deviations for all parabens were below 10.8%.

An insight into the determination of trace levels of benzodiazepines in biometric systems: Use of crab shell powder as an environmentally friendly biosorbent.

A vortex assisted dispersive solid phase extraction approach (VADSPE) based on crab shell powder as biodegradable and biocompatible µ-sorbent was developed for simultaneous analysis of three benzodiazepines (BZPs): Oxazepam, Flurazepamand Diazepam, in biological matrixes included blood, nail, hair and urine samples. The effective parameters in VADSPE process, including the volume of uptake solvent, the dosage of sorbent, extraction time and back extraction time, were optimized using response surface methodology(RSM) based on central composite design(CCD). The suggested technique allows successful trapping of BZPs in a single-step extraction. Under the optimized extraction conditions, the proposed approach was exhibited low limits of detection (0.003-1.2 µg·mL-1), an acceptable linearity (0.04-20 µg·mL-1). Method performance was assessed by recovery experiments at spiking levels of 10 µg·mL-1(n = 5) for BZPs in blood, nail, hair and urine samples. Relative recoveries were determined by HPLC, which were between 36%and 95.6%.

Fabrication and characterization of metal organic frameworks/ polyvinyl alcohol cryogel and their application in extraction of non-steroidal anti-inflammatory drugs in water samples.

A series of novel MOFs/PVA composite cryogel (MIL-101(Cr)/PVA, MIL-100(Fe)/PVA, ZIF-8(Zn)/PVA, MOF-199(Cu)/PVA and MIL-53(Al)/PVA) were fabricated by using a facile and green freeze-thaw approach for the first time. MIL-101(Cr)/PVA cryogel was selected as a VA-SPE sorbent for extraction of four NSAIDs in environmental water samples. The procedures of condition investigation (synthesis and extraction optimization) and characterization were also performed. And a satisfactory result of methodology validation was obtained by making use of HPLC-MS/MS. Under the optimum conditions, good sensitivity levels were achieved with the limits of detection between 0.007 and 0.037 µg L-1, a linearity of 0.10-10 µg L-1 for phenylbutazone, indomethacin, nimesulide and 0.020-2.0 µg L-1 for benorilate (r2 ≥ 0.9934). The relative recoveries of the target analytes were in the range from 78.44% to 105.7% with relative standard deviation (RSD) from 1.33% to 9.85%. In the extraction process, MIL-101(Cr)/PVA cryogel as a whole sheet outperformed the pristine dispersive MIL-101(Cr) in separation from solvent, and the application of cryogel also simplified the operation procedure. Additionally, the combination of PVA with MOFs might strengthen the interaction ability between the sorbent and analytes. This novel pretreatment method had a variety of merits, such as easy operation, high enrichment efficiency and low matrix effect. It looks forward to further optimization or functionalization and application of these MOFs/PVA cryogel in various disciplines.

Zirconium-based highly porous metal-organic framework (MOF-545) as an efficient adsorbent for vortex assisted-solid phase extraction of lead from cereal, beverage and water samples.

In this study, zirconium-based highly porous metal-organic framework, MOF-545, was synthesized and characterized. The surface area of MOF-545 was found to be 2192m2/g. This adsorbent was used for the first time as an adsorbent for the vortex assisted-solid phase extraction of Pb(II) from cereal, beverage and water samples. Lead in solutions was determined by FAAS. The optimal experimental conditions were as follows: the amount of MOF-545, 10mg; pH of sample, 7; adsorption and elution time, 15min; and elution solvent, 2mL of 1molL-1HCl. Under the optimal conditions of the method, the limit of detection, preconcentration factor and precision as RSD% were found to be 1.78µgL-1, 125 and 2.6%, respectively. The adsorption capacity of the adsorbent for lead was found to be 73mgg-1. The method was successfully verified by analyzing two certified reference materials (BCR-482 Lichen and SPS-WW1 Batch 114) and spiked chickpea, bean, wheat, lentil, cherry juice, mineral water, well water and wastewater samples.