Facial synthesis of fluorine-engineered magnetic covalent organic framework for selective and ultrasensitive determination of fipronil, its metabolites and analogs in food samples.

To improve the adsorption affinity and selectivity of fipronils (FPNs), including fipronil, its metabolites and analogs, a magnetic covalent organic framework (Fe3O4@COF-F) with copious fluorine affinity sites was innovatively designed as an adsorbent of magnetic solid-phase extraction (MSPE). The enhanced surface area, pore size, crystallinity of Fe3O4@COF-F and its exponential adsorption capacities (187.3-231.5 mg g-1) towards fipronils were investigated. Combining MSPE with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), an analytical method was established for the selective determination of fipronils in milk and milk powder samples. This method achieved high sensitivity (LODs: 0.004-0.075 ng g-1), satisfactory repeatability and accuracy with spiked recoveries ranging from 89.9% to 100.3% (RSDs≤5.1%). Overall, the constructed Fe3O4@COF-F displayed great potential for the selective enrichment of fipronils, which could be ascribed to fluorine­fluorine interaction. This method proposed a feasible and promising strategy for the development of functionalized COF and broadened its application in fluorine containing hazards detection.

Facile synthesis of magnetic ionic covalent organic framework and dispersive magnetic solid phase extraction of aromatic amino acid oxidation products in thermally processed foods.

Aromatic amino acid oxidation products (AAAOPs) are newly discovered risk substances of thermal processes. Due to its significant polarity and trace level in food matrices, there are no efficient pre-treatment methods available to enrich AAAOPs. Herein, we proposed a magnetic cationic covalent organic framework (Fe3O4@EB-iCOF) as an adsorbent for dispersive magnetic solid-phase extraction (DMSPE). Benefiting from the unique charged characteristics of Fe3O4@EB-iCOF, AAAOPs can be enriched through electrostatic interaction and π-π interactions. Under the optimal DMSPE conditions, the combined HPLC-MS/MS method demonstrated good linearity (R2 ≥ 0.990) and a low detection limit (0.11-7.5 µg·kg-1) for AAAOPs. In addition, the method was applied to real sample and obtained satisfactory recoveries (86.8 % âˆ¼ 109.9 %). Especially, we applied this method to the detection of AAAOPs in meat samples and conducted a preliminarily study on its formation rules, which provides a reliable basis for assessing potential dietary risks.

[Determination of 13 kinds of free and bound phenolic acids in fruits by high-performance liquid chromatography-mass spectrometry].

OBJECTIVE: To establish a high-performance liquid chromatography-mass spectrometry(HPLC-MS/MS) method for detecting 13 kind of free and bound phenolic acids(chlorogenic acid, protocatechuic acid, ferulic acid, p-coumaric acid, gallic acid, gentisic acid, vanillic acid, caffeic acid, syringic acid, sinapic acid, rosmarinic acid, salicylic acid, p-hydroxybenzoic acid) in fruits, and optimize the pre-treatment conditions to meet the detection requirements for phenolic acid content in various types of fruits. METHODS: Free phenolic acids in fruits were extracted using methanol through ultrasonic extraction. Conjugated phenolic acids in the centrifuged residue were released by alkaline hydrolysis and extracted with ethyl acetate. The two extracts were combined, concentrated, and analyzed using HPLC-MS/MS. Separation was achieved using an Agilent ZORBAX SB-C_(18) chromatography column(3.0 mm×100 mm, 3.5 µm), and detection was performed in multiple reaction monitoring(MRM) mode. RESULTS: All 13 standard phenolic acids achieved complete separation within 10 minutes, with linear correlation coefficients greater than 0.998 and detection limits ranging from 0.172 to 3.471 ng/mL. After optimization of the pre-treatment method, the recovery rates of the method for four types of fruits-apples, strawberries, oranges, and peaches-ranged from 80.0% to 119.4%, and the precision were lower than 7.00%(n=6). The result of testing on four categories of twelve types of fruits demonstrated significant variations in the content of phenolic acids among different fruits, and within the same category, the composition of phenolic acids did not exhibit consistency. CONCLUSION: The HPLC-MS/MS method exhibits high sensitivity, precision, and accuracy. It is suitable for the detection of both free and bound phenolic acids in various types of fruits.

Qualitative Profiling, Antioxidant and Antimicrobial Activities of Polar and Nonpolar Basil Extracts.

Basil (Ocimum basilicum L.) is a widely used culinary herb. In this study, ethanol, dichloromethane, and sunflower oil were used separately as solvents with distinct polarities for the extraction of basil aerial parts to simulate the different polarity conditions in domestic food processing. The oil extract (OE) was re-extracted with acetonitrile, and the chemical composition, antioxidant potential, and antimicrobial activities of the ethanol (EE), dichloromethane (DCME), and acetonitrile (ACNE) extracts were determined. A total of 109 compounds were tentatively identified in EE, DCME, and ACNE by HPLC-DAD/ESI-ToF-MS. Fatty acids were present in all extracts. Phenolic acids and flavonoids dominated in EE. DCME was characterised by triterpenoid acids, while diterpenoids were mainly found in ACNE. The extracts were analysed for their antioxidant capacity using the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) assay. EE and DCME showed significant radical scavenging potential. Antimicrobial activity was explored in eight bacterial, two yeast, and one fungal species. All extracts exhibited high antifungal activity, comparable to or better than that of the commercial drug nistatin. Antibacterial activities were notable for EE and ACNE, while DCME showed no activity against bacteria in the applied concentration ranges. The different polarities of the solvents led to distinctive phytochemical compositions and bioactivities in the extracts.

Phenolic compounds profile in extracts of Smilax spp., antioxidant activity, and inhibition of advanced glycation end products.

Smilax genus possesses bioactive properties attributed to phenolic compounds, which may exhibit antioxidant effects and inhibit the advanced glycation end products (AGEs). However, identifying these phenolic compounds and AGEs has become increasingly relevant to understanding such activities. This study aimed to identify phenolic compounds in extracts of Smilax spp. and evaluate their antioxidant and AGEs inhibitory activities. To achieve this, the Smilax genus was identified via PCR, and phenolic compounds including chlorogenic acid, naringenin-6-C-glucoside, quercetin, quercetin-3-O-glucoside, and myricetin were identified using HPLC-MS/MS. Antioxidant activity was assessed by ferric reducing antioxidant power (FRAP), and radicals such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2'-azino-bis-[3-ethyl-benzothiazoline]-6-sulfonic acid (ABTS), while AGEs inhibition was evaluated using a model system formed by bovine serum albumin-glucose. The highest antioxidant activity was 3612.18 mM TE/g, and the inhibition of AGEs was 52.44 %. These results demonstrate that Smilax spp. can inhibit AGEs, neutralize free radicals, and reduce compounds associated with antioxidant capacity.

Potential for the Bio-Detoxification of the Mycotoxins Enniatin B and Deoxynivalenol by Lactic Acid Bacteria and Bacillus spp.

Mycotoxins, toxic compounds produced by fungi, pose significant risks to food safety and human health. This study investigates the bio-detoxification potential of 238 strains of lactic acid bacteria (LAB) and Bacillus spp., previously isolated from cereals (including mycotoxin-contaminated grains), against the emerging mycotoxin, enniatin B (ENB), and the prevalent mycotoxin, deoxynivalenol (DON). Out of the tested strains, 26 demonstrated notable mycotoxin reduction capabilities, including 2 Bacillus pumilus and 24 Bacillus licheniformis strains. B. licheniformis strains MA572, MA695, MA696, TR174a, TR284, TR363, and TR466a degraded ENB to levels below the detection limit, and six strains reduced DON by 30-35%; B. licheniformis TR251b and TR374 showed the highest DON reduction with 35.7%. The most promising strains for bio-detoxification were B. licheniformis TR284, which achieved a 100% reduction in ENB and a 28.6% reduction in DON and B. licheniformis TR388 with a 97.5% reduction in ENB and a 31.9% reduction in DON. None of the tested LAB strains significantly reduced either mycotoxin. These findings highlight the promising potential of B. licheniformis strains in bio-detoxifying mycotoxin-contaminated cereal products. Further research into the underlying detoxification mechanisms and safety aspects is essential to develop effective bio-detoxification strategies for enhancing food safety.

The relationship between CYP2C9 gene polymorphisms and azilsartan metabolism in vitro.

BACKGROUND: The gene polymorphisms of the CYP2C9, as well as the substrate specificity of the enzyme, result in different clearances for different substrates by CYP2C9 variants. RESEARCH DESIGNAND METHODS: The CYP2C9 wild type and 38 CYP2C9 variants, expressed in insectmicrosomes, were incubated with azilsartan. The resulting metabolite,O-desethyl azilsartan, was determined by HPLC-MS/MS. The enzyme kineticparameters of the 38 variants were calculated and compared with the wild type.Subsequently, we selected CYP2C9*1, *2, and *3 as target proteins for molecular docking with azilsartan to elucidate the mechanisms underlying changes in enzyme function. RESULTS: Compared with CYP2C9*1, three variants (CYP2C9*29, *39, and *49) exhibited markedlyincreased CLint values (from 170%-275%, *p < 0.05), whereas 28 variants exhibited significantly decreased CLint values (from 3-63%,*p < 0.05). The molecular docking results showed that the binding energy of CYP2C9*2 and *3 was lower than that of the wild type. CONCLUSION: Thisassessment revealed the effect of CYP2C9 gene polymorphisms on azilsartan metabolism, establishing a theoretical basis for further in-vivo studies and clinical applications. This study will help expand the database of CYP2C9 gene-drug pairs and identify appropriate treatment strategies for azilsartan, contributing to the field of precision medicine.

A practical HPLC-MS method for the analysis of nitrosamine drug substance related impurities using an inexpensive single quadrupole mass spectrometer.

Nitrosamine drug substance related impurities (NDSRIs) are often analyzed using high performance liquid chromatography (HPLC) with mass spectrometry (MS) detection. Due to high sensitivity requirements, high resolution MS or MS/MS is commonly used. However, it is difficult to implement this type of method for routine analysis at a supply site. Herein, we report a systematic approach to develop and validate a practical, robust, and user-friendly method for the analysis of NDSRIs using an inexpensive single quadrupole MS instrument such as QDa. We used 7-nitroso-3-(trifluoromethyl)-5,6,7,8-tetrahydro- [1,2,4] triazolo [4,3-a] pyrazine (NTTP) as an example to demonstrate the method development process. By optimizing the HPLC and MS parameters, we were able to develop a simple HPLC-MS method that provides the desired specificity and sensitivity for the analysis of NTTP and can be easily implemented in an analytical lab. The limit of quantitation is 0.5 ng/mL, corresponding to 0.1 ppm with respect to 5 mg/mL sitagliptin. The method has been successfully validated per ICH guidelines.

Applying UHPLC-HRAM MS/MS Method to Assess Host Cell Protein Clearance during the Purification Process Development of Therapeutic mAbs.

Host cell proteins (HCPs) are one of the process-related impurities that need to be well characterized and controlled throughout biomanufacturing processes to assure the quality, safety, and efficacy of monoclonal antibodies (mAbs) and other protein-based biopharmaceuticals. Although ELISA remains the gold standard method for quantification of total HCPs, it lacks the specificity and coverage to identify and quantify individual HCPs. As a complementary method to ELISA, the LC-MS/MS method has emerged as a powerful tool to identify and profile individual HCPs during the downstream purification process. In this study, we developed a sensitive, robust, and reproducible analytical flow ultra-high-pressure LC (UHPLC)-high-resolution accurate mass (HRAM) data-dependent MS/MS method for HCP identification and monitoring using an Orbitrap Ascend BioPharma Tribrid mass spectrometer. As a case study, the developed method was applied to an in-house trastuzumab product to assess HCP clearance efficiency of the newly introduced POROS™ Caprylate Mixed-Mode Cation Exchange Chromatography resin (POROS Caprylate mixed-mode resin) by monitoring individual HCP changes between the trastuzumab sample collected from the Protein A pool (purified by Protein A chromatography) and polish pool (purified by Protein A first and then further purified by POROS Caprylate mixed-mode resin). The new method successfully identified the total number of individual HCPs in both samples and quantified the abundance changes in the remaining HCPs in the polish purification sample.

Structural and spectroscopic characterization of N1,N2-diphenylacenapthylene-1,2-diimines and the influence of substituents on the viscosity of alkyl magnesium solutions.

Butyl octyl magnesium solutions are important raw materials in various chemical processes but suffer from their high reactivity with even traces of water, protic solvents or oxygen and an increased viscosity in hydrocarbon solution due to the formation of polymeric structures. N1,N2-diphenylacenaphthylene-1,2-diimines (BIANs) have already been identified as potential candidates to reduce the viscosity of alkyl magnesium solutions and this study provides a systematic insight into the dependence of this ability on the position and structures of substituents on the BIAN. Besides the various BIANs, ZnCl2 complexes and hydrogenated derivatives were characterized and tested for their ability to reduce the viscosity. HPLC-high resolution mass spectrometry, MALDI-ToF mass spectrometry, but most important FTIR and NMR experiments under inert conditions have been used to shine light on the interaction of the different BIAN derivatives with alkyl magnesium solutions. Hydrogenated BIANs, especially those with bulky alkyl groups in the ortho position(s) have been identified as the most promising candidates. An additional benefit of the hydrogenated species is that in contrast to BIANs and BIAN-Zn complexes they do not undergo permanent chemical modification and can be reused after extraction.

Extraction, Identification, and Antioxidant Activity of Flavonoids from Hylotelephium spectabile (Boreau) H. Ohba.

The extraction of total flavonoids from Hylotelephium spectabile (Boreau) H. Ohba (H. spectabile) leaves was studied through the use of a double enzyme-assisted ultrasonic method, and the extraction process was optimized using the Box-Behnken design. Eight different macroporous resins were screened for purification in single-factorial experiments, and the flavonoid compounds in the extract of H. spectabile leaves were identified using HPLC-MS. Through the evaluation of the total reducing capacity and capacity for reducing 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH), hydroxyl radicals (·OH), and 2,2'-biazobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), the in vitro antioxidant activities of the crude extracts of the total flavonoids and purified total flavonoids of H. spectabile leaves were investigated. The results showed that the most efficient conditions for flavonoid extraction were an ultrasonic extraction time of 60 min, an ethanol concentration of 35%, a liquid-to-material ratio of 20:1 mL/g, and an amount of enzyme (cellulose/pectinase = 1:1) of 1.5%, forming H. spectabile powder. Under these conditions, the total flavonoid extraction rate in the H. spectabile leaf extract was 4.22%. AB-8 resin showed superior performance in terms of purification, and the optimal adsorption and desorption times were 1.5 h and 3 h, respectively. The recommended parameters for purification included a liquid volume of 5.5 BV, a flow rate of 1.2 BV/min, a pH of 5, and a concentration of 0.8 mg/mL. The observed order for reducing capacity was ascorbic acid (VC) > rutin > purified total flavonoids > crude extract of total flavonoids. The purified total flavonoid extract from H. spectabile showed a good scavenging ability against DPPH, ·OH, and ABTS·+, suggesting strong antioxidant activity. Therefore, this study can serve as technical support and reference data for the further development and utilization of H. spectabile resources.

A simple HPLC-MS/MS method for the determination of polymyxin B in human plasma and its application in the pharmacokinetic study in elderly patients infected with multidrug-resistant Gram-negative bacteria.

Introduction: Polymyxin B is widely used to treat infections caused by multidrug-resistant Gram-negative bacteria. However, the pharmacokinetic study data of PB in the elderly are scarce. Herein, a simple method to measure the concentration of PB in human plasma was developed and validated by high performance liquid chromatography-tandem mass spectrometry, and it was applied to a PK study in the elderly. Methods: PB was extracted from human plasma by a rapid protein-precipitation method using 0.1% formic acid in methanol and then separated on an ultimate AQ-C18 column using linear gradient elution with a 0.5-mL/min flow rate. Subsequently, PB was detected using a mass spectrometer operated in positive-ion and multiple-reaction-monitoring modes. Results: The lower limits of quantification of the method for Polymyxin B1 and Polymyxin B2 were 1.00 and 0.10 µg/mL, respectively. The linear ranges for PB1 and PB2 were 1.00-20.02 and 0.10-2.04 µg/mL, respectively. Patients receiving a 75-mg maintenance dose every 12h had AUCss, 24 h, and Css, av values of 117.70 ± 37.03 µg h/mL and 4.14 ± 1.74 µg/mL, respectively. For patients receiving a 100 mg maintenance dose, these values were 152.73 ± 70.09 µg h/mL and 5.43 ± 2.85 µg/mL, respectively. Conclusion: The validated HPLC-MS/MS method was successfully applied to a study on the pharmacokinetics of PB in elderly patients infected with multidrug-resistant Gram-negative bacteria. Both two dose strategies in this study would have a excessive PB exposure in the elderly patients then the therapeutic window recommended by guidelines.

[Analysis of 5 patients with acute glyphosate poisoning clinical characteristics and metabolic concentration].

Objective: To analyze the correlation between changes in the concentration of glyphosate (GLY) and its metabolites (AMPA) in patients with acute glyphosate poisoning and clinical symptoms, and to provide reference for the study of glyphosate toxicity. Methods: Urine samples from 5 patients with oral glyphosate poisoning admitted to the Emergency Department of Yangzhou Third Class A General Hospital from February to July 2021 were collected. Urine concentrations of GLY and AMPA were measured using derivatization gas chromatography-mass spectrometry, and analyzed based on the patient's clinical manifestations and treatment process. Results: The main symptoms of the patient after poisoning were acute gastrointestinal symptoms, such as nausea, vomiting, abdominal pain, etc. The concentration of GLY in the patient's urine reached its maximum on the first day and gradually decreased over time. On the day of discharge, the final concentration of GLY was 10% lower than the initial concentration. At discharge, the clearance rates of GLY in cases 1, 2, 3, and 4 were 96.97%, 95.91%, 96.87% and 92.87%, respectively. Conclusion: The glyphosate has a shorter maintenance time after entering the human body; There is no correlation between the concentration of glyphosate and its metabolites admitted to the hospital, the dose of poisoning, and clinical symptoms in poisoned patients.

Magnetic conjugated microporous polymer for rapid extraction and sensitive analysis of environmental endocrine disruptors in environmental waters and dairy products.

BACKGROUND: Environmental endocrine disruptors (EEDs) are a class of new pollutants that are diffusely used in the medical industry and animal husbandry. In view of toxicity concerns, elevated levels of EEDs in the environment and food, which cause potential harm to human beings and ecosystems, must be monitored. Determination of EEDs contaminants to ensure environment and food safety has became a major concern worldwide, it is also a challenging task because of their trace level and probable matrices interference. Thus, developing rapid adsorption and efficient analysis methods for EEDs is apparently necessary. RESULTS: A magnetic conjugated micro-porous polymer (Fe3O4@TbDt) was designed and synthesized, which was endowed with large specific surface area, rich functional groups and magnetic responsiveness. The material showed high extraction efficiency for EEDs via magnetic solid-phase extraction (MSPE). The quantum chemistry calculations showed the adsorption mechanism of Fe3O4@TbDt on EEDs mainly included electrostatic interactions, van der waals forces (N-H … π interaction, C-H … π interaction), and multiple hydrogen bonds. Finally, a trace analysis method for nine EEDs was established combined with HPLC-MS/MS under optimized MSPE conditions. The method showed a good linearity (R2 ≥ 0.996), low limits of detection (0.25-5.1 ng L-1), high precision (RSD of 1.1-8.2 %, n = 6). The applicability of this method was investigated by analyzing four water samples and two dairy products, and satisfactory recovery rates (82.1-100.7 %) were obtained. The proposed method showed the potential for the analysis of EEDs residues in food and environmental samples. SIGNIFICANCE: The developed MSPE method based on conjugated micro-porous polymers (CMPs) is simple, green, and efficient compared to existing techniques. The application of CMPs provides a new idea for preparing versatile sample pre-treatment materials. What's more, this work has certain reference value for addressing of EEDs residues in the environment and food.

Comparing the impact of conventional and non-conventional processing technologies on water-soluble vitamins and color in strawberry nectar - a pilot scale study.

A comprehensive comparison was conducted on the effect of conventional thermal processing (TT), high-pressure processing (HP), pulse electric field (PF), and ohmic heating (OH) on water-soluble vitamins and color retention in strawberry nectar. The ascorbic acid (AA) content increased by 15- and 9-fold after TT and PF treatment, respectively, due to rupturing of cells under heat stress and release of intracellular AA. Dehydroascorbic acid (DHA) content did not change considerably after TT and PF treatment but significantly decreased after HP and OH treatment. TT treatment offered the highest total vitamin C retention. The B vitamins remained largely unchanged after processing, with the highest loss of 34 % for riboflavin in OH-treated samples. All the technologies resulted in similar color retention after processing. The study concludes with a standardized comparison of mainstream preservation technologies using pilot-scale equipment. Such an approach significantly increases the applicability of the results presented in the study.

A validated HPLC-MS/MS method for the simultaneous determination of ecdysteroid hormones in subminimal amounts of biological material.

Ecdysteroids represent a large class of polyhydroxylated steroids which, due to their anabolic properties, are marketed as dietary supplements. Some ecdysteroids also act as important hormones in arthropods, where they regulate molting, development, and reproduction and many of these insects are miniature organisms that contain submicroliter levels of circulating biofluids Analysis of ecdysteroids is further complicated by their very low abundance, large fluctuations during development, and difficult access to a pooled sample, which is important for quantitative measurements. In this work, we propose a new method that overcomes the described difficulties and allows validated quantification of four ecdysteroids in minimal amounts of biological material. After methanolic extraction, detectability of the ecdysteroids is increased 16- to 20-fold by conversion to their 14,15-anhydrooximes. These are further purified by pipette tip solid phase extraction (PT-SPE) on a three-layer sorbent and subjected to HPLC-MS/MS analysis. Full validation was achieved using hemolymph from larvae of the firebug Pyrrhocoris apterus as a blank matrix and by the determination of ecdysteroids in a single Drosophila larva. The LLOQs for the four target ecdysteroids (20-hydroxyecdysone, ecdysone, makisterone A, and 2-deoxyecdysone) were 0.01; 0.1; 0.05; 0.025 pg·mL-1 (20; 200; 100; 50 fmol·mL-1) respectively, with very good accuracy, precision (RSD < 15%) and recoveries (96% - 119.9%).The general suitability of the new method was demonstrated by quantification of ecdysteroids in various biological materials including human serum.

LC-MS analysis of chiral amino acids in human urine reveals D-amino acids as potential biomarkers for colorectal cancer.

Colorectal cancer (CRC) is a common malignant tumor in the gastrointestinal tract. Changes in amino acid metabolites have been implicated in tumorigenesis and disease progression. Biomarkers on the basis of chiral amino acids, especially D-amino acids, have not been established for early diagnosis of CRC. Quantification of chiral amino acids, especially very low concentrations of endogenous D-amino acids, is technically challenging. We report here the quantification of L- and D-amino acids in urine samples collected from 115 CRC patients and 155 healthy volunteers, using an improved method. The method of chiral labeling, liquid chromatography, and tandem mass spectrometry enabled separation and detection of 28 amino acids (14 L-amino acids, 13 D-amino acids and Gly). Orthogonal partial least squares discriminant analysis identified 14 targeted variables among these chiral amino acids that distinguished the CRC from the healthy controls. Binary logistic regression analysis revealed that D-α-aminobutyric acid (D-AABA), L-alanine (L-Ala), D-alanine (D-Ala), D-glutamine (D-Gln) and D-serine (D-Ser) could be potential biomarkers for CRC. A receiver operating characteristic curve analysis of combined multi-variables contributed to an area under the curve (AUC) of 0.995 with 98.3 % sensitivity and 96.8 % specificity. A model constructed with D-AABA, D-Ala, D-Gln, and D-Ser achieved an AUC of 0.988, indicating important contributions of D-amino acids to the association with CRC. Further analysis also demonstrated that the metabolic aberration was associated with age and the development of CRC, D-methionine (D-Met) was decreased in CRC patients with age over 50, and D/L-Gln in patients at stage IV was higher than patients at stage I. This study provides the signature of D-amino acids in urine samples and offers a promising strategy for developing non-invasive diagnosis of CRC.

Core-shell magnetic covalent organic polymer nanocomposites as an adsorbent for the extraction of flavonoids.

A novel 3D magnetic nanocomposite material based on covalent organic polymers was successfully synthesized and utilized as an efficient sorbent for magnetic solid-phase extraction. It exhibited a regular core-shell structure, large specific surface area, superior stability, and paramagnetism. To evaluate its extraction efficiency, six flavonoids were tested, demonstrating maximum adsorption capacities ranging from 90 to 218 mg/g. Additionally, the material exhibited remarkable reusability and mechanical stability, maintaining its original state over eight cycles with consistent recovery. An analytical strategy combining magnetic solid-phase extraction with high performance liquid chromatography and tandem mass spectrometry was developed for the determination of flavonoids in orange, honey, soybean, and Dioscorea bulbifera L. samples. The low limits of detection (0.01-0.1 ng/mL) and limits of quantification (0.05-0.5 ng/mL), as well as satisfactory recovery (80.4-114.8%), were obtained. The linear range started from the limits of quantification to 500 ng/mL with R2 ≥ 0.9929. These results suggest that the prepared adsorbent possesses excellent adsorption capabilities for flavonoids, highlighting its significant potential for detecting these compounds in complex sample matrices.

On-site extraction of benzophenones from swimming pool water using hybrid tapes based on the integration of hydrophilic-lipophilic balance microparticles and an outer magnetic nanometric domain.

An on-site extraction device is presented consisting of scotch tape modified with concentric domains of micrometric hydrophilic-lipophilic balance (HLB) particles surrounded by a ring of nanometric magnetic ones. On the one hand, HLB microparticles are readily available at the surface of the tape, exposed to interact with the target analytes, being responsible for the extraction capacity of the sorptive phase. On the other hand, the presence of magnetic nanoparticles enables the attachment of the modified tape onto a metallic screw via a magnet, which is then coupled to a wireless drill, enabling the stirring of the microextraction device. Both are simply fixed to the cost-effective, flexible, and versatile support, i.e., scotch tape, owing to their adhesive properties. The microextraction device has been applied to the determination of six benzophenones in swimming pool water samples. The variables that may affect the extraction process have been evaluated. Under the optimum conditions and using liquid chromatography-tandem mass spectrometry as the instrumental technique, the method provided a limit of detection of 0.03 µg L-1. The intra-day precision, evaluated at three different concentration levels and expressed as relative standard deviation, was lower than 10%, which also comprises the variability within single-use sorptive tapes. The accuracy, calculated with spiked samples and expressed as relative recovery, ranged from 71 to 138%. The method was applied to the analysis of swimming pool water, revealing the presence of such compounds.

[Zirconium-based metal-organic framework composites for solid phase extraction of brevetoxin-A from seawater].

Red tides are a type of natural marine disaster caused by harmful algae characterized by a high toxicity, wide distribution, and long duration. Since the concentration of algal toxins in seawater increases with the occurrence of red tides, algal toxins detected in seawater could be used to predict the occurrence and evolution of red tides. Brevetoxin-A (BTX-A) is a secondary metabolite produced by the harmful algae Karenia brevis, whose detection in seawater could form the basis of an accurate warning system for incoming red tides. However, due to the inherent complexity of the seawater matrix and the extremely low levels of BTX-A in seawater, the use of instruments for its direct detection is difficult. Therefore, there is an urgent need to develop a sample pretreatment method for the efficient enrichment of BTX-A in seawater. In this study, a metal-organic backbone material (UiO-66) and its composite with silica microspheres (SiO2@UiO-66) were successfully synthesized using the solvothermal method. The prepared SiO2@UiO-66 exhibited good hydrophilicity, water stability, and large specific surface area. Furthermore, it also exhibited hydrogen bonding and electrostatic interactions with BTX-A, had a strong affinity for BTX-A, and was able to efficiently adsorb BTX-A in complex matrices. Therefore, SiO2@UiO-66 showed potential as a novel packing material for the extraction of BTX-A from solid phase extraction columns. Combined with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), a highly sensitive detection method for the determination of BTX-A in marine water was established. The established analytical method had a low detection limit (3.0 pg/mL), a wide linear range (10.0 -200.0 pg/mL), and a good linear relationship (R=0.9992). Combined with the Fujian Province Red Tide Monitoring and Early Warning Information 2021 issued by the Fujian Provincial Oceanic and Fisheries Bureau, the analytical method established herein was successfully applied to analyze and monitor the content of BTX-A in actual seawater samples. This highlights the proposed system's potential for use as an early warning factor in the monitoring of red tides, representing a simple and fast pretreatment methodology for the detection of BTX-A in seawater.