Formic Acid Research Articles

An efficient synthesis, structural analysis, and computational studies of benzothiazole derivatives activated by formic acid under solvent-free conditions

In the present work, formic acid was used as a low-cost and eco-friendly catalyst to synthesize 2-(2-hydroxyphenyl)benzothiazole (HB) through a cycloaddition process in a solvent-free reaction medium. Imine molecule was synthesized with the help of acetic acid (B). The ring closure and formation of the thiazole moiety give acetic acid distinctiveness as a catalyst. The cyclization of fused HB failed without an acid catalyst. The chemical structures were characterized using microanalysis techniques such as IR, 1H-NMR, and 13C-NMR. The obtained FT-IR spectra were compared to theoretical data using the B3LYP/6-31G* level of theory. The electronic characteristics of molecules can be predicted utilizing wave function-dependent features, such as Average localized ionization energy (ALIE), Localized orbital locator (LOL), Electron localized function (ELF), Reduced density gradient (RDG), and Noncovalent interactions NCI studies, which have provided a wealth of knowledge. The molecular docking study was investigated to explore binding energy and interaction type. Docking analysis displayed binding energies (kcal/mol) of HB with values of -8.29, -6.80, -6.68, -7.43, and -6.69 of acetylcholinesterase (AChE) and butylcholinesterase (BuChE)), SARS-CoV-2 main protease (Mpro), human immunodeficiency virus reverse transcription (HIV RT)) and cytochrome (P450), respectively, which was the most active compound against all receptors. The dramatic improvement of the proposed approach over the existing methods can be used to derive an efficient and successful route for the synthesis of HB. This process provides a fresh and high-yield method for the synthesis of benzimidazoles.

Determination of vancomycin and meropenem in serum and synovial fluid of patients with prosthetic joint infections using UPLC-MS/MS.

Numerous studies have suggested that intra-articular administration of antibiotics following primary revision surgery may be one of the methods for treating prosthetic joint infection (PJI). Vancomycin and meropenem are the two most commonly used antibiotics for local application. Determining the concentrations of vancomycin and meropenem in the serum and synovial fluid of patients with PJI plays a significant role in further optimizing local medication schemes and effectively eradicating biofilm infections. This study aimed to establish a rapid, sensitive, and accurate ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for determining the concentrations of vancomycin and meropenem in human serum and synovial fluid. Serum samples were processed using acetonitrile precipitation of proteins and dichloromethane extraction, while synovial fluid samples were diluted before analysis. Chromatographic separation was achieved in 6min on a Waters Acquity UPLC BEH C18 column, with the mobile phase consisting of 0.1% formic acid in water (solvent A) and acetonitrile (solvent B). Quantification was carried out using a Waters XEVO TQD triple quadrupole mass spectrometer with an electrospray ionization (ESI) source in positive ion mode. The multiple reaction monitoring (MRM) mode was employed to detect the following quantifier ion transitions: 717.95-99.97 (norvancomycin), 725.90-100.04 (vancomycin), 384.16-67.99 (meropenem). The method validation conformed to the guidelines of the FDA and the Chinese Pharmacopoeia. The method demonstrated good linearity within the range of 0.5-50 μg/ml for serum and 0.5-100 μg/ml for synovial fluid. Selectivity, intra-day and inter-day precision and accuracy, extraction recovery, matrix effect, and stability validation results all met the required standards. This method has been successfully applied in the pharmacokinetic/pharmacodynamic (PK/PD) studies of patients with PJI.

Systems metabolic engineering of Corynebacterium glutamicum to assimilate formic acid for biomass accumulation and succinic acid production

Formate as an ideal mediator between the physicochemical and biological realms can be obtained from electrochemical reduction of CO2 and used to produce bio-chemicals. Yet, limitations arise when employing natural formate-utilizing microorganisms due to restricted product range and low biomass yield. This study presents a breakthrough: engineered Corynebacterium glutamicum strains (L2-L4) through modular engineering. L2 incorporates the formate-tetrahydrofolate cycle and reverse glycine cleavage pathway, L3 enhances NAD(P)H regeneration, and L4 reinforces metabolic flux. Metabolic modeling elucidates C1 assimilation, guiding strain optimization for co-fermentation of formate and glucose. Strain L4 achieves an OD600 of 0.5 and produces 0.6 g/L succinic acid. 13C-labeled formate confirms C1 assimilation, and further laboratory evolution yields 1.3 g/L succinic acid. This study showcases a successful model for biologically assimilating formate in C. glutamicum that could be applied in C1-based biotechnological production, ultimately forming a formate-based bioeconomy.

N-doped hollow carbon nanospheres embedded in N-doped graphene loaded with palladium nanoparticles as an efficient electrocatalyst for formic acid oxidation

N-doped hollow carbon nanospheres embedded in N-doped graphene loaded with palladium nanoparticles as an efficient electrocatalyst for formic acid oxidation

Reciprocal crosslink among MeCP2/BDNF /CREB signaling pinpointed in autism spectrum disorder.

Autism spectrum disorder, or individual disability (ID), is a condition characterized by complications in social interaction, restricted repetitive behavior, and difficulties in social communication. Neuquinon (NQ) possess a powerful therapeutic potential in various neurodegenerative disease. Nevertheless, contributing to NQ's low water solubility and bioavailability, its medicinal use has been constrained. Liposomes were supposed to be prospective drug-delivering agents for NQ, crossing the blood-brain barrier (BBB), and reaching the target organs. The current investigation aims to track the signaling pathways that govern NQ and liposomal neuquinon (LNQ) action in autistic models generated by ethyl formic acid. The neurotransmitters gamma amino-butyric acid (GABA), acetylcholine (ACh), and acetylcholinesterase (AChE) in addition to, the gene expressions of brain-derived neurotrophic factor (BDNF), cAMP response element-binding protein (CREB), and methyl-CpG-binding protein 2 (MeCP2) and the DNA damage COMET analysis at different time intervals of the study, were assessed. EFA in a dose of 500mg/kg BW was used to induce autism in rats, and then NQ and LNQ were administered in 10mg/kg and 2mg/kg BW, respectively. The results revealed that NQ and LNQ significantly down-regulated BDNF, GABA, and AChE; on the other hand, they up-regulated MeCP2, CREB gene expressions, and ACh action. NQ and LNQ displayed improvement in DNA damage in almost all brain regions after EFA alterations; even better results were noticed post-LNQ therapy. Therefore, it may be concluded that neuquinon and liposomal-loaded neuquinon have a therapeutic index versus EFA-induced autism in a rat model.

Paradigm Shift: Major Role of Ion-Pairing-Dependent Size Exclusion Effects in Bottom-Up Proteomics Reversed-Phase Peptide Separations.

Can reversed-phase peptide retention be the same for C8 and C18 columns? or increase for otherwise identical columns with a smaller surface area? Can replacing trifluoroacetic acid (TFA) with formic acid (FA) improve the peak shape? According to our common understanding of peptide chromatography, absolutely not. Surprisingly, a thorough comparison of the peptide separation selectivity of 100 and 120 Å fully porous C18 sorbents to maximize the performance of our in-house proteomics LC-MS/MS setup revealed an unexpectedly higher peptide retentivity for a wider pore packing material, despite it having a smaller surface area. Concurrently, the observed increase in peptide retention─which drives variation in separation selectivity between 100 and 120 Å pore size materials─was more pronounced for smaller peptides. These findings contradict the central dogmas that underlie the development of all peptide RP-HPLC applications: (i) a larger surface area leads to higher retention and (ii) increasing the pore size should benefit the retention of larger analytes. Based on our intriguing findings, we compared reversed-phase high-performance liquid chromatography peptide retention for a total of 20 columns with pore sizes between 60 and 300 Å using FA- and TFA-based eluents. Our results unequivocally attest that the larger size of ion pairs in FA- vs TFA-based eluents leads to the observed impact on selectivity and peptide retention. For FA, peptide retention peaks at 200 Å pore size, compared to between 120 and 200 Å for TFA. However, the decrease in retention for narrow-pore particles is more profound in FA. Our findings suggest that common assumptions about analyte size and accessible surface area should be revisited for ion-pair RP separation of small peptides, typical for proteomic applications that are predominantly applying FA eluents. Hybrid silica-based materials with pore sizes of 130-200 Å should be specifically targeted for bottom-up proteomic applications to obtain both superior peak shape and peptide retentivity. This challenging task of attaining the best RPLC column for proteomics calls for closer collaboration between LC column manufacturers and proteomic LC specialists.

Covalent-Organic-Framework-Modified Quartz Crystal Microbalance Sensor for Selective Detection of Hazardous Formic Acid.

Covalent organic frameworks (COFs) are a novel family of porous crystalline materials utilized in various advanced applications. However, applying COFs as a hazardous organic acid gas sensor is substantial but still challenging. Herein, a phenylenediamine-based covalent organic framework (TPDA-TPB COF) featuring excellent crystallinity, ultrastable thermal stability, and high surface area was successfully constructed. Then, the TPDA-TPB COF-modified quartz crystal microbalance (QCM) sensor is fabricated by immobilizing the TPDA-TPB COF thin film on the gold-QCM chip. The fabricated TPDA-TPB COF-modified QCM sensor demonstrates a rapid response, excellent reproducibility, high selectivity, and sensitivity to formic gas, arising from hydrogen-bonding interactions between formic acid and the outermost layer of the TPDA-TPB COF, as determined by extensive analysis and density functional theory calculations. The basic sites of the TPDA-TPB COF, which are numerous due to its high nitrogen content, and the carboxylic acid groups present in formic acid exhibit efficient interactions. The sensitivity of the TPDA-TPB COF-modified QCM sensor was found to be 7.75 Hz ppm-1 at standard room temperature and pressure conditions, with a limit of detection (LOD) of formic acid down to 1.18 ppm, which is significantly below the workplace olfactory threshold limit of 5.0 ppm established by the Occupational Safety and Health Administration. The TPDA-TPB COF-modified QCM sensor exhibits remarkable detecting capabilities, making it highly attractive for detecting organic acid vapors in diverse applications that require superior performance.

Development and validation of a high-performance liquid chromatography with tandem mass spectrometry method for quantification of tofacitinib in human plasma

Introduction. The use of tofacitinib as a pharmacological treatment for rheumatoid arthritis remains relevant in the light of the predicted increase in prevalence of the disease. At the same time, due to the withdrawal of several foreign pharmaceutical companies from the Russian pharmaceutical market, there has been a heightened demand for domestically produced medications, including generic formulations of tofacitinib. Registration of generic drugs necessitates the conduct of bioanalytical studies. Development and validation of a method for quantifying the analyte in biosamples remains to be a crucial part of the bioequivalence studies.Aim. The aim of this research is to develop and validate a method for the quantitative determination of tofacitinib in human plasma using high-performance liquid chromatography as the separation system coupled with a tandem mass spectrometer for detection purposes.Materials and methods. Biosample preparation was based on plasma proteins precipitation using acetonitrile. Baricitinib was selected as an internal standard. The analytical range of the method was 1.00 to 200.00 ng/mL and was further expanded to 0.30 to 200.00 ng/mL during the analytical phase of the study. The mobile phase consisted of water and acetonitrile, both acidified with formic acid (0.1 % v/v). The stationary phase was a Phenomenex Kinetex C18 column [100 × 3.0 mm, with a particle size of 5 µm (Phenomenex, USA)]. Sample separation and detection were carried out using high-performance liquid chromatography coupled with a tandem mass spectrometry (HPLC-MS/MS), operating in positive ion mode. The multiple reaction monitoring (MRM) transitions selected for the analyte and the internal standard were 313.30 to 173.00 m/z and 371.90 to 186.00 m/z, respectively.Results and discussion. The developed assay was validated in accordance with the current requirements of regulatory documentation from the EAEU (Eurasian Economic Union), FDA (US Food and Drug Administration), and EMA (European Medicines Agency) with the following parameters being evaluated: selectivity, specificity, carry-over, matrix effect, recovery, calibration curve, lower limit of quantitation, accuracy, precision, stability. The validated method was applied in the analytical part of a bioequivalence study of domestically produced generic tofacitinib.Conclusion. A method for the quantitative determination of tofacitinib in human blood plasma with an analytical range of 0.30–200.00 ng/mL was developed and validated. Application of the assay during the analytical phase of bioequivalence study of generic tofacitinib confirms the possibility of using the method in similar bioanalytical investigations.

Coordination-induced amidated modified polyacrylonitrile loaded ultrafine palladium nanoparticles for thermocatalytic hydrogen evolution

A promising approach for powering hydrogen fuel cells (HFCs) involves the in-situ production of hydrogen from formic acid decomposition, with Pd-based catalysts recognized as effective for formic acid dehydrogenation. However, the immobilization of ultrafine palladium nanoparticles (Pd NPs) on catalytic supports presents a challenge and necessitates further investigation into their formation mechanism. We propose a coordination-induced strategy to understand the behavior of ultrafine Pd NPs formation based on multi-functional groups. To establish the structure–activity relationship for tunable Pd microenvironment and catalytic performance, we synthesized various polyacrylonitrile (PAN) carriers through hydrolysis and amidation modification. Molecular dynamics simulations confirmed that a stronger coordination-induced microenvironment facilitates the dispersion of Pd2+, suppressing aggregation and enhancing Pd loading. Our experimental results and density functional theory (DFT) calculations demonstrated that the catalytic activity of Pd@APAN(15_1%) with ultrafine Pd NPs (1.5 nm) exhibits over 10 times higher than that of Pd@PAN NPs with the turnover of frequency climbing from 112.6 h−1 to 1309.4 h−1 at 323 K. And Pd-imine and Pd-secondary amine moieties were verified to contribute to the creation of a favorable catalysis microenvironment. This study provides new insights into the design of modified supports with various groups to load well-dispersed and ultrafine Pd for highly efficient catalysts based on a coordination-induced strategy.

Unraveling the Oxidation Mechanism of Formic Acid on Pd(111) Electrode: Implication from pH Effect and H/D Kinetic Isotope Effect

Unraveling the Oxidation Mechanism of Formic Acid on Pd(111) Electrode: Implication from pH Effect and H/D Kinetic Isotope Effect

Prediction of mass spectrometry ionization efficiency based on COSMO-RS and machine learning algorithms.

Non-targeted analysis of high-resolution mass spectrometry (MS) can identify thousands of compounds, which also gives a huge challenge to their quantification. The aim of this study is to investigate the impact of mass spectrometry ionization efficiency on various compounds in food at different solvent ratios and to develop a predictive model for mass spectrometry ionization efficiency to enable non-targeted quantitative prediction of unknown compounds. This study covered 70 compounds in 14 different mobile phase ratio environments in positive ion mode to analyze the rules of the matrix effect. With the organic phase ratio from low to high, most compounds changed by 1.0 log units in log IE. The addition of formic acid enhanced the signal but also promoted the matrix effect, which often occurred in compounds with strong ionization capacity. It was speculated that the matrix effect was mainly in the form of competitive charge and charged droplet' gasification sites during MS detection. Subsequently, we present a log IE prediction method built using the COSMO-RS software and the artificial neural network (ANN) algorithm to address this difficulty and overcome the shortcomings of previous models, which always ignore the matrix effect. This model was developed following the principles of QSAR modeling recommended by the Organization for Economic Cooperation and Development (OECD). Furthermore, we validated this approach by predicting the log IE of 70 compounds, including those not involved in the log IE model development. The results presented demonstrate that the method we put forward has an excellent prediction accuracy for log IE (R2pred = 0.880), which means that it has the potential to predict the log IE of new compounds without authentic standards.

PH-Universal Electrocatalytic CO2 Reduction with Ampere-level Current Density on Doping-engineered Bismuth Sulfide.

The practical application of the electrocatalytic CO2 reduction reaction (CO2RR) to form formic acid fuel is hindered by the limited activation of CO2 molecules and the lack of universal feasibility across different pH levels. Herein, we report a doping-engineered bismuth sulfide pre-catalyst (BiS-1) that S is partially retained after electrochemical reconstruction into metallic Bi for CO2RR to formate/formic acid with ultrahigh performance across a wide pH range. The best BiS-1 maintains a Faraday efficiency (FE) of ~95% at 2000 mA cm-2 in a flow cell under neutral and alkaline solutions. Furthermore, the BiS-1 catalyst shows unprecedentedly high FE (~95%) with current densities from 100 to 1300 mA cm-2 under acidic solutions. Notably, the current density can reach 700 mA cm-2 while maintaining a FE of above 90% in a membrane electrode assembly electrolyzer and operate stably for 150 h at 200 mA cm-2. In-situspectra and density functional theory calculations reveals that the S doping modulates the electronic structure of Bi and effectively promotes the formation of the HCOO* intermediate for formate/formic acid generation. This work develops the efficient and stable electrocatalysts for sustainable formate/formic acid production.

An LC-MS/MS method for the simultaneous determination of 6-cyanodopamine, 6-nitrodopamine, 6-nitrodopa, 6-nitroadrenaline and 6-bromodopamine in human plasma and its clinical application in patients with chronic kidney disease.

The aim of this study was to develop a high-performance liquid chromatography-tandem mass spectrometry method for the determination of 6-cyanodopamine, 6-nitrodopamine, 6-nitrodopa, 6-nitroadrenaline and 6-bromodopamine in human plasma samples. Strata-X 33 μm solid-phase extraction cartridges were used for the extraction of the catecholamines from human plasma samples. The catecholamines were separated in a 150 × 3 mm Shim-pack GIST C18-AQ column with 3μm particle size, placed in an oven at 40°C and perfused with 82% mobile phase A (acetonitrile-H2O; 90:10, v/v) + 0.4% acetic acid and 18% mobile phase B (deionized H2O) + 0.2% formic acid at a flow rate of 340 μl/min in isocratic mode. The injected volume was 4 μl and the run lasted 4 min. The method was linear from 0.1 to 20 ng/ml and the lower limit of quantification was 0.1 ng/ml for all analytes. The method was applied to evaluate the plasma levels of catecholamines in plasma of patients with chronic kidney disease and allowed the detection for the first time of circulating levels of the novel catecholamines 6-bromodopamine and 6-cyanodopamine.

Ultra-Large Two-Dimensional Metal Nanowire Networks by Microfluidic Laminar Flow Synthesis for Formic Acid Electrooxidation.

Despite the great research interest in two-dimensional metal nanowire networks (2D MNWNs) due to their large specific surface area and abundance of unsaturated coordination atoms, their controllable synthesis still remains a significant challenge. Herein, a microfluidics laminar flow-based approach is developed, enabling the facile preparation of large-scale 2D structures with diverse alloy compositions, such as PtBi, AuBi, PdBi, PtPdBi, and PtAuCu alloys. Remarkably, these 2D MNWNs can reach sizes up to submillimeter scale (~220 μm), which is significantly larger than the evolution from the 1D or 3D counterparts that typically measure only tens of nanometers. The PdBi 2D MNWNs affords the highest specific activity for formic acid (2669.1 mA mg-1) among current unsupported catalysts, which is 103.5 times higher than Pt-black, respectively. Furthermore, in situ Fourier transform infrared (FTIR) experiments provide comprehensive evidence that PdBi 2D MNWNs catalysts can effectively prevent CO* poisoning, resulting in exceptional activity and stability for the oxidation of formic acid.

Ultra‐Large Two‐Dimensional Metal Nanowire Networks by Microfluidic Laminar Flow Synthesis for Formic Acid Electrooxidation

Despite the great research interest in two‐dimensional metal nanowire networks (2D MNWNs) due to their large specific surface area and abundance of unsaturated coordination atoms, their controllable synthesis still remains a significant challenge. Herein, a microfluidics laminar flow‐based approach is developed, enabling the facile preparation of large‐scale 2D structures with diverse alloy compositions, such as PtBi, AuBi, PdBi, PtPdBi, and PtAuCu alloys. Remarkably, these 2D MNWNs can reach sizes up to submillimeter scale (~220 μm), which is significantly larger than the evolution from the 1D or 3D counterparts that typically measure only tens of nanometers. The PdBi 2D MNWNs affords the highest specific activity for formic acid (2669.1 mA mg‐1) among current unsupported catalysts, which is 103.5 times higher than Pt‐black, respectively. Furthermore, in situ Fourier transform infrared (FTIR) experiments provide comprehensive evidence that PdBi 2D MNWNs catalysts can effectively prevent CO* poisoning, resulting in exceptional activity and stability for the oxidation of formic acid.

Hydrogen‐Bond‐Mediated Formation of C−N or C=N Bond during Photocatalytic Reductive Coupling Reaction over CdS Nanosheets

AbstractReductive amination of carbonyl compounds and nitro compounds represents a straightforward way to attain imines or secondary amines, but it is difficult to control the product selectivity. Herein, we report the selective formation of C−N or C=N bond readily manipulated through a solvent‐induced hydrogen bond bridge, facilitating the swift photocatalytic reductive coupling process. The reductive‐coupling of nitro compounds with carbonyl compounds using formic acid and sodium formate as the hydrogen donors over CdS nanosheets selectively generates imines with C=N bonds in acetonitrile solvent; while taking methanol as solvent, the C=N bonds are readily hydrogenated to the C−N bonds via hydrogen‐bonding activation. Experimental and theoretical study reveals that the building of the hydrogen‐bond bridge between the hydroxyl groups in methanol and the N atoms of the C=N motifs in imines facilitates the transfer of hydrogen atoms from CdS surface to the N atoms in imines upon illumination, resulting in the rapid hydrogenation of the C=N bonds to give rise to the secondary amines with C−N bonds. Our method provides a simple way to control product selectivity by altering the solvents in photocatalytic organic transformations.

Determination of fraxetin, fraxin and dimethylfraxetin in rat plasma by UPLC-MS/MS

AbstractObjectiveThe levels of fraxetin, fraxin, and dimethylfraxetin in rat plasma to be measured using an ultra-performance liquid chromatography tandem mass-spectrometry (UPLC–MS/MS) technique and applied to their pharmacokinetics and bioavailability.MethodsThe protein precipitation technique was applied to the plasma preparation using acetonitrile and methanol (9:1, v/v). At a flow rate of 0.4 mL min−1, the elution time was 6 min. The mobile phase consisted of acetonitrile-water with 0.1% formic acid, and the chromatographic column was UPLC HSS T3 (50 mm × 2.1 mm, 1.8 μm). Quantitative analysis was conducted using multiple reaction monitoring (MRM) mode and detection was performed using electrospray ionization (ESI) positive ion mode. In each group, six rats were treated with fraxetin, fraxin, and dimethylfraxetin either orally (5 mg kg−1) or intravenously (1 mg kg−1).ResultsThe calibration curves showed good linearity in the range of 2–4,000 ng mL−1, where r was greater than 0.99. The bioavailability of dimethylfraxetin, fraxin, and fraxetin was determinated to be 19.7, 1.4, and 6.0%.ConclusionThe established UPLC-MS/MS method for determining the levels of these three compounds in rat plasma was successfully applied to the pharmacokinetics of dimethylfraxetin, fraxin, and fraxetin, and the bioavailability was calculated.

Rapid determination of four flavonoids from hawthorn leaves in plasma by ultra‐high performance liquid chromatography‐tandem mass spectrometry and study on its pharmacokinetics

AbstractIn this study, a rapid and sensitive ultra‐high performance liquid chromatography‐tandem mass spectrometry method was established for the simultaneous determination of four Vitexin‐4“‐O‐glucoside (VOG), Vitexin‐2”‐O‐rhamnoside (VOR), vitexin (VIT), and hyperoside (HP) in plasma, which are representative flavonoids constituents of hawthorn leaves. The four components were separated by CORTECS UPLC C18 column (100 × 3.0 mm, 1.6 µm), using acetonitrile‐water containing 0.02% formic acid and 2 mmol/L ammonium formate as the mobile phase, the gradient elution flow rate was 0.30 mL/min. The analyte was quantified using an electrospray ionization triple quadrupole mass spectrometer. The analytes and baicalin internal standard were performed at m/z 593.2/413.2 for VOG, m/z 577.2/413.1 for VOR, m/z 431.1/310.9 for VIT, m/z 463.2/300 for HP and m/z 445.1/269 for internal standard. Among the four flavonoids, the correlation coefficient of the standard curve of each component is between 0.9939 and 0.9987. After oral administration of hawthorn leaf extract, VOG and VOR showed similar pharmacokinetic characteristics; VIT was eliminated in the body more slowly than the other three flavonoids and distributed more in the tissues; HP can be quickly absorbed in the blood. The developed analytical method has high sensitivity, precision, and accuracy with no interference from plasma components and has been successfully used in pharmacokinetic studies.

Quantitation of tazemetostat in human plasma using liquid chromatography-tandem mass spectrometry.

To support a phase 1 trial in patients with lymphomas, we developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for tazemetostat quantitation in 20 μL of human plasma. After protein precipitation, chromatographic separation employed a Kinetex C18 column and a gradient of 0.1% formic acid in both water and acetonitrile, during a 3-min run time. Detection was achieved using a SCIEX 6500+ tandem mass spectrometer with electrospray positive-mode ionization. Validation was based on the latest Food and Drug Administration guidance. With a stable isotopic internal standard, the assay was linear within the range of 10-5000 ng/mL and proved to be accurate (91.9%-103.7%) and precise (<4.4% imprecision). Recovery varied between 93.3% and 121.1%, and matrix effect ranged from -25.5% to -4.9%. Hemolysis, lipemia, and dilution did not impact quantitation. Plasma stability was confirmed after three freeze-thaw cycles, 24 h at room temperature, and 4months at -80°C. Incurred sample reanalysis yielded 94.4% samples within 20% difference (n = 36). External validation showed a mean bias of -11.1%. Pharmacokinetic (PK) data obtained from three patients suggested variable concentration time profiles, warranting collection of further data. The assay proved to be suitable for tazemetostat quantitation in human plasma and will support clinical studies by defining tazemetostat PKs.

Carboxylic acid modulated in situ growth of Zr-based MOFs on carboxylated cotton fabrics for removal of Cr(VI) from aqueous solutions

In this paper, carboxylated cotton fabric (CF-Ph-COOH) were obtained as active substrate by diazonium radical polymerization modification of cotton fibers. Then the MOF fabric composites were prepared by in situ growth of metal zirconium ions (Zr) and organic ligands on the surface of carboxylated cotton fabrics under carboxylic acid modifier. MOF fabric composites with controllable morphologies structures were achieved by regulating organic ligands, reaction time the type and dosage of regulator (formic acid and acetic acid). The prepared acetic acid regulated MOF fabric composites were designated as CF-HAc1-UiO-66, CF-HAc2-UiO-66, CF-HAc1-UiO-66-NH2, and CF-HAc2-UiO-66-NH2, respectively, and the formic acid regulated as CF-FA-UiO-66 and CF-FA-UiO-66-NH2. The fabricated carboxylic acid modulated MOF fabric composites were well characterized using SEM, TGA, XRD, FTIR, and XPS spectra. The adsorption experiment results show that carboxylic acid modulated Zr based MOF fabric composites can serve as adsorbent for effective removal of Cr(VI) from water, in which the CF-FA-UiO-66-NH2 was prepared under the ratio of ZrCl4 and BDC-NH2 is 1.006 and with 5.47 M formic acid regulator exhibits that the optimal adsorption efficiency and the removal efficiency is 79.5 %. In addition, the adsorption of Cr(VI) in water by CFA-UiO-66-NH2 showed a quasi-secondary kinetic model following the Langmuir adsorption model, showing a a typical of chemisorption. What’s more, the Cr(VI) removal efficiency and saturated adsorption capacity of CF-FA-UiO-66-NH2 was up to 80 % and 318.85 mg/g, respectively. The prepared CF-FA-UiO-66-NH2 MOF fabric composite was recyclable for removal of Cr(VI), and could be used as the potential adsorbent membrane for waste water treatment.