Combination Of Liquid Chromatography Research Articles

Quantification of SARS-CoV-2 monoclonal IgG mass fraction by isotope dilution mass spectrometry.

The availability of serology assays to measure antibodies against the SARS coronavirus 2 (SARS-CoV-2) expanded rapidly during the Covid-19 pandemic. The interchangeable use of such assays to monitor disease progression and immune protection requires their standardization, for which suitably characterized monoclonal antibody materials can be useful. The methods, based on isotope dilution mass spectrometry, to value assign the mass fraction of such a material in solution within the context of an international interlaboratory comparison study (CCQM-P216) are described. The mass fraction in solution of a humanized IgG monoclonal antibody (mAb) against the SARS-CoV-2 Spike glycoprotein in the study sample has been value assigned through a combination of liquid chromatography, isotope dilution mass spectrometry (LC-ID-MS) methods and size exclusion chromatography with UV detection (SEC-UV). The former were developed for the quantification of amino acids and proteotypic peptides as surrogate analytes of the mAb while the latter was applied for the determination of the relative monomeric mass fraction. High-resolution mass spectrometry (hrMS) allowed the molecular weight evaluation and ruled out the presence of significant impurities. Method trueness was assessed using a subclass homologous IgG1 material value assigned by amino acid analysis. The assigned mass fraction of monomeric SARS-CoV-2 IgG in solution was 390 ± 16mg/g. The associated expanded uncertainty originated mainly from acid hydrolysis variability and Trypsin/Lys-C digestion variability and efficiency.

Active Compounds of Red Ginger as Antioxidant Activity in the Supplementation and Treatment of Depression

This study examined compound active of red ginger related for supplementation and treatment of depression. Depression prevalence in Indonesia from the national population survey 6.9% had severe depression symptoms, 21.8% moderate to severe. Red ginger provided gold potential and demonstrated prominent natural phenomena and coexistence, abundant benefits. Standard herbal medicine and phytopharmaceuticals as one effort in dealing with depression disorder. Problem Statement. The use of medicines for depression disorder in the long term becomes a serious problem affecting various sectors and needs to be thought of side effects and complications. Objective. Antioxidants in red ginger (Zingiber Officinale Rosc. Var Rubrum has a secondary metabolite considered for treatment or supplementation in depression disorders. This study was experimental analytical study for analyzing secondary metabolism using phytochemical screening tests and examining active compounds with the combination of liquid chromatography with tandem mass spectrometry (LCMS/MS).Red ginger extracts contain secondary metabolic flavonoids of 48.79 mgQE/g, phenol 92.73 mgGAE/G and antioxidants of 39.96 ppm. Establishment of the active compound that has an effect as an antioxidant α-Eleostearic acid (C18 H30 O2) chemspider result 10, mzcloud 96, L Histidine (C6 H9 N3 O2) chemspiders result 6, mzcloud 94,8. Tetrahydrocurcumin (C21 H24 O6) chemspider result 41, mzcloud 92,5. Active compounds of red ginger antioxidants are diarylheptanoid, phenylbutenoid, flavonoid, diterpenoide, sesquiterpenoid, gingerol and shogaol. Red ginger extract content of active flavonoid compounds and has an effect as an antioxidant is potentially used as a supplement in the treatment of depression disorders.

Temperature-responsive comprehensive two-dimensional liquid chromatography coupled to high resolution mass spectrometry for the elucidation of the oxidative degradation processes of chemicals of environmental concern

This study explores the possibilities offered by temperature-responsive liquid chromatography (TRLC) based comprehensive 2-dimensional liquid chromatography in combination with reversed-phase liquid chromatography (RPLC) for the analysis of degradation products formed upon oxidative treatment of persistent organic pollutants, in this case exemplified through carbamazepine (CBZ). The TRLC×RPLC combination offers the possibility to overcome peak overlap and incomplete separation encountered in 1D approaches, while the transfer of the purely aqueous mobile phase leads to refocusing of all analytes on the second dimension column. Consequently, this allows for about method-development free and hence, easier LC×LC. The study focuses on the oxidative degradation of CBZ, a compound of environmental concern due to its persistence in water bodies. The TRLC×RPLC combination effectively separates and identifies CBZ and its degradation products, while offering improved selectivity over the individual TRLC or RPLC separations. This allows gathering more understanding of the degradation cascade and allows real-time monitoring of the appearance and disappearance of various degradation products. The compatibility with high-resolution mass spectrometry is last shown, enabling identification of 21 CBZ-related products, nine of which were not previously reported in CBZ degradation studies. The approach's simplicity, optimization-free aspects, and ease of use make it a promising tool for the analysis of degradation pathways in environmental contaminants.

Toward a More Comprehensive Approach for Dissolved Organic Matter Chemical Characterization Using an Orbitrap Fusion Tribrid Mass Spectrometer Coupled with Ion and Liquid Chromatography Techniques.

Dissolved organic matter (DOM) represents one of the largest active organic carbon pools in the global carbon cycle. Although extensively studied, only <10% of DOM has been chemically characterized into individual dissolved compounds due to its molecular complexity. This study introduced a more comprehensive DOM characterization method by coupling both ion chromatography (IC) and liquid chromatography (LC) with high mass accuracy and resolution mass spectrometry. We presented a new on-the-fly mass calibration of the Orbitrap technique by utilizing the "lock mass" function in the Orbitrap Fusion Tribrid mass spectrometer (OT-FTMS), which assures high mass accuracy at every scan by a postcolumn introduction of internal labeled standards. With both IC and LC, tested unlabeled standards of amino acids, small peptides, and organic acids were consistently below 1.0 ppm mass error, giving the OT-FTMS the potential of reaching mass accuracy of the Fourier-transform ion cyclotron resonance mass spectrometer. In addition to mass accuracy, a pooled quality control sample (QC) was used to increase reproducibility by applying systematic error removal using random forest (SERRF). Using an untargeted mass spectrometry approach, estuarine DOM samples were analyzed by OT-FTMS coupled to IC in negative mode and LC in positive mode detection to cover a wide range of highly cationic to highly anionic molecules. As a proof of concept, we focused on elucidating the structures of three distinct DOM compound classes with varied acidities and basicities. In UPLC-OT-FTMS, a total of 915 compounds were detected. We putatively elucidated 44 small peptides and 33 deaminated peptides of these compounds. With IC-OT-FTMS, a total of 1432 compounds were detected. We putatively elucidated 20 peptides, 268 deaminated peptides, and 188 organic acids. Except for five compounds, all putatively elucidated compounds were uniquely detected in their corresponding chromatography technique. These results highlight the need for combining these two techniques to provide a more comprehensive method for DOM characterization. Application of the combined IC and LC techniques is not limited to DOM chemical characterization. It can analyze other complex compound mixtures, such as metabolites, and anthropogenic pollutants, such as pesticides and endocrine-disrupting chemicals, in environmental and biological samples.

Combining Liquid Chromatography and Cryogenic IR Spectroscopy in Real Time for the Analysis of Oligosaccharides.

While the combination of liquid chromatography (LC) and mass spectrometry (MS) serves as a robust approach for oligosaccharide analysis, it has difficulty distinguishing the smallest differences between isomers. The integration of infrared (IR) spectroscopy within a mass spectrometer as an additional analytical dimension can effectively address this limitation by providing a molecular fingerprint that is unique to each isomer. However, the direct interfacing of LC-MS with IR spectroscopy presents a technical challenge arising from the mismatch in the operational time scale of each method. In previous studies, this temporal incompatibility was mitigated by employing strategies designed to slow down or broaden the LC elution peaks of interest, but this workaround is applicable only for a few species at a time, necessitating multiple LC runs for comprehensive analysis. In the current work, we directly couple LC with cryogenic IR spectroscopy by acquiring a spectrum in as little as 10 s. This allows us to generate an orthogonal data dimension for molecular identification in the same amount of time that it normally takes for LC analysis. We successfully demonstrate this approach on a commercially available human milk oligosaccharide product, acquiring spectral information on the eluting peaks in real time and using it to identify both the specified constituents and nonspecified product impurities.

A powerful two-dimensional chromatography method for the non-target analysis of depolymerised lignin

BackgroundLignin is an abundant natural polymer obtained as a by-product from the fractionation of lignocellulosic biomass. In the name of a circular economy, lignin should be valorised into valuable chemicals or biomaterials and utilised instead of petrochemicals. For the development of efficient valorisation processes, the structural characterisation of lignin can be highly beneficial. However, this is an arduous task, as the isolated (and sometimes processed) lignin mainly consists of various neutral monomers but also oligomers. In addition, the material contains isomers, which can be especially problematic to separate and identify. ResultsWe present a powerful off-line comprehensive two-dimensional (2D) chromatography method combining liquid chromatography (LC), supercritical fluid chromatography (SFC), and high-resolution mass spectrometry for the non-target analysis of depolymerised lignin. The implementation of a 1-aminoanthracene column in the second dimension enabled a class separation of potential lignin monomers, dimers, trimers, and tetramers with an additional separation based on the number of hydroxyl groups and steric effects. The pentafluorophenyl column in the first dimension additionally improved the separation based on hydrophobicity. The comparison of off-line 2D LC × SFC to 1D SFC showed that besides the overall improved performance, the first method is also superior for the separation of isomers. Advanced data analysis methods (MS-DIAL, SIRIUS, and Feature-Based Molecular Network) were integrated into the non-target workflow to rapidly visualise and study the detected compounds, which proved to be especially beneficial for the characterisation of the separated isomers. SignificanceThe method yielded the first 2D LC plot demonstrating a classification of lignin compounds, which can be applied to compare various lignin sources and processing methods. In addition, the technique demonstrated improved separation of compounds, including isomers, which was especially beneficial as 77 % of the detected compounds had at least one isomer in the same lignin sample.

Effects of pH-dependent speciation on the photolytic degradation mechanism of phosphonates

Phosphonates, commonly used as strong metal chelating agents in household and industrial products, partially persist through water treatment processes, releasing significant amounts into the environment and raise concerns about potential environmental impacts. This study investigated effects of pH-dependent speciation of phosphonates on their photolysis by a medium-pressure mercury lamp in aqueous solution under ambient air conditions. Different species of aminotrimethylphosphonic acid (ATMP), and its most important transformation products iminodimethylphosphonic acid(IDMP) and aminomethylphosphonic acid(AMPA) were analyzed by liquid chromatography in combination with isotope ratio (CSIA) and high resolution mass spectrometry. UV radiation (<320 nm) was required for the photolytic degradation of ATMP, IDMP, and AMPA, and their photolysis was influenced by pH-dependent speciation. Degradation rate constant of ATMP was affected by pH, but a direct correlation between kobs and pH was not found. In contrast, IDMP and AMPA exhibited a direct correlation between pH and kobs during photolysis. CSIA revealed an inverse carbon kinetic isotope effect (KIE) for ATMP, while a normal carbon KIE was observed for IDMP and AMPA. Quantum chemical calculations supported degradation pathway interpretation and KIE understanding. Energy barrier calculations distinguished N-C vs C-P bond cleavage, favoring N-C cleavage on average, consistent with observed transformation products. Further calculations, considering possible transition states, provide first promising hints for elucidation of present KIEs.

Integrating Metabolomics and Network Pharmacology to Explore the Mechanism of Xiao-Yao-San in the Treatment of Inflammatory Response in CUMS Mice.

Depression can trigger an inflammatory response that affects the immune system, leading to the development of other diseases related to inflammation. Xiao-Yao-San (XYS) is a commonly used formula in clinical practice for treating depression. However, it remains unclear whether XYS has a modulating effect on the inflammatory response associated with depression. The objective of this study was to examine the role and mechanism of XYS in regulating the anti-inflammatory response in depression. A chronic unpredictable mild stress (CUMS) mouse model was established to evaluate the antidepressant inflammatory effects of XYS. Metabolomic assays and network pharmacology were utilized to analyze the pathways and targets associated with XYS in its antidepressant inflammatory effects. In addition, molecular docking, immunohistochemistry, Real-Time Quantitative Polymerase Chain Reaction (RT-qPCR), and Western Blot were performed to verify the expression of relevant core targets. The results showed that XYS significantly improved depressive behavior and attenuated the inflammatory response in CUMS mice. Metabolomic analysis revealed the reversible modulation of 21 differential metabolites by XYS in treating depression-related inflammation. Through the combination of liquid chromatography and network pharmacology, we identified seven active ingredients and seven key genes. Furthermore, integrating the predictions from network pharmacology and the findings from metabolomic analysis, Vascular Endothelial Growth Factor A (VEGFA) and Peroxisome Proliferator-Activated Receptor-γ (PPARG) were identified as the core targets. Molecular docking and related molecular experiments confirmed these results. The present study employed metabolomics and network pharmacology analyses to provide evidence that XYS has the ability to alleviate the inflammatory response in depression through the modulation of multiple metabolic pathways and targets.

Schisandrin and Schisantherin A in Multiphytoadaptogen for Preventive Oncology

Background. The original herbal formula of Multiphytoadaptogen (MPhA) for preventive oncology developed by the N. N. Blokhin Center of Oncology containing phytocomponents from Schisandra chinensis (Turcz.) Baill (Schisandraceae), has been investigated in vitro, in vivo. Preliminary efficiency in clinical trials has also been obtained. This was allowed because MPhA in Russia is registered as a parapharmaceutical agent and therefore standardized according to established requirements. However, due to the high efficiency of MPhA, a detailed study of the chemical composition and standardization of it is required, including the Schisandra chinensis active components, which turned out to be translocated into MPhA as a result of the extraction technology developed.The aim of the study was to identify the Schisandra chinensis biologically active substances in MPhA and to evaluate the biological activity profiles of the identified phytocomponents using in silico analysis.Materials and methods. we used high performance liquid chromatography in combination with mass spectrometry (HPLC–MS / MS). Chromatography was performed on an ACQUITY UPLC BEH C18 column in a gradient mode. A TSQ Vantage triple quadrupole mass spectrometer with electrospray ionization was used. we performed in silico analyzes of Schisandrin and Schisantherin A biological activity spectra using computer programs PASS and PharmaExpert.Result. The secondary metabolites lignans Schisandrin and Schisantherin A were identified in the herbal formula MPhA. Schisandrin and Schisantherin A activities, according the scientific literature and in silico analysis, correspond to the properties studied for MPhA which therefore fits into the concept of medication for preventive oncology.Conclusion. The determined secondary metabolites can be used for identification, standardization and quality testing of the herbal formula MPhA.

Structural Identification of Impurities in Pioglitazone Hydrochloride Preparations by 2D-UHPLC-Q-Exactive Orbitrap HRMS and Their Toxicity Prediction.

Pharmaceutical companies and regulatory agencies have more and more concerns for impurities in pharmaceuticals and their toxicity. In this work, heart-cutting two-dimensional ultrahigh-performance liquid chromatography (2D-UHPLC) in combination with high-resolution mass spectrometry (HRMS) was used, setting HRMS as positive mode of electrospray ionization to identify five impurities in pioglitazone hydrochloride preparations. With the heart-cutting 2D-UHPLC and online desalting technique, the structures of five impurities were deduced in an analysis of MSn data. And three of them, Impurity-2, Impurity-3, and Impurity-5, have never been reported before. The fragmentation patterns of five impurities were proposed on a basis of accurate mass and fragment ions in this study. Since the toxicity of impurities is relevant to their structures, toxicology of all five impurities was predicted by three software tools, and the result showed that these compounds have good safety profile.

THU400 Parameters Of Vitamin D Metabolism, Calcium And Phosphate Homeostasis In Patients Undergoing Bariatric Surgery

Abstract Disclosure: A. Zhukov: Grant Recipient; Self; Russian Science Foundation (project 19-15-00243-P). A. Povaliaeva: Grant Recipient; Self; Russian Science Foundation (project 19-15-00243-P). Z. Abilov: Grant Recipient; Self; Russian Science Foundation (project 19-15-00243-P). L. Usoltseva: None. D. Trukhina: None. E. Pigarova: Grant Recipient; Self; Russian Science Foundation (project 19-15-00243-P). L. Rozhinskaya: Grant Recipient; Self; Russian Science Foundation (project 19-15-00243-P). Objective: to evaluate the parameters of vitamin D metabolism and calcium and phosphate homeostasis in patients undergoing bariatric surgery. Materials and Methods: The study included 10 patients without chronic kidney disease and mineral metabolism disorders who underwent laparoscopic gastric bypass surgery for obesity. After surgery, all patients were recommended to take cholecalciferol depending on the initial level of 25-OH D in blood in accordance with the Endocrine Society Clinical Practice Guideline. Ninety nine [96; 130] days after the surgery, the levels of vitamin D metabolites: D3, 25-OH D3, 24,25-OH2 D3, 1,25-OH2 D3 were determined by ultra-high performance liquid chromatography in combination with tandem mass spectrometry (certified by DEQAS) as well as the PTH, total calcium, albumin, creatinine, phosphorus, magnesium levels in serum. Results: Median age of the patients was 39 [34; 50] years, 80% women, 90% initially had type 2 diabetes mellitus (BMI before surgery 49.1 [39.7; 51.0] kg/m2, median decrease in BMI by the time of inclusion in the study 8.3 [8.0; 9.2] kg/m2). The median level of 25-OH D3 was 28.5 [24.6; 32.0] ng/ml (1 patient had a level less than 20 ng/ml, 6 patients from 20 to 30 ng/ml), D3 levels were below the laboratory sensitivity threshold (12.5 ng/ml) in all participants. The median 24,25-OH2 D3 level was 1.49 [1.04; 1.95] ng/ml (reference interval (RI) 0.5-5.6 ng/ml), the median 25-OH D3/24,25-OH2 D3 ratio was 21.87 [15.57; 22.55] (RI 7-23). All patients had normal levels of 1,25-OH2 D3 (median 45.95 [35.18; 53.65] pg/ml, RI 25-66). One patient had secondary hyperparathyroidism (albumin-adjusted calcium 2.14 mmol/l, RI 2.15-2.55; PTH 73.8 pg/ml, RI 15-65; 25-OH D3 24.8 ng/ml) while other biochemical parameters were normal. The remaining patients had normal levels of PTH, calcium, phosphorus and magnesium. Conclusions: The revealed changes in the levels of D3 and 25-OH D3 in patients undergoing bariatric surgery may be due to malabsorption, increased deposition in adipose tissue, an insufficient dosage of cholecalciferol or low patient compliance. At the subsequent stages of vitamin D metabolism, no abnormalities were identified. It is likely that this cohort of patients requires higher doses of cholecalciferol. Presentation: Thursday, June 15, 2023

Determination of 15 Functional State Biomarkers in Human Urine by High-Performance Liquid Chromatography with Tandem Mass Spectrometric Detection

The capabilities and limitations of complex procedures for targeted metabolomic analysis using liquid chromatography in combination with tandem mass spectrometry (HPLC-MS/MS) are discussed. An HPLC-MS/MS procedure for the simultaneous determination of the concentrations of 15 biomarkers of the functional state of a human being in urine is presented. The target analytes are biogenic substances of various chemical natures, the basic concentrations of which in biomatrices can vary significantly, up to three orders of magnitude or more. Complex analysis is also difficult to perform due to significant differences in the hydrophilic and hydrophobic properties of the analytes. The testing of the procedure in a bioanalytical experiment made it possible to establish significant differences in the concentrations of a number of biomarkers in the urine of persons with different levels of physical fitness. With a high level of physical fitness, the concentrations of these compounds in urine have lower values in comparison with those in the control group.

Jiawei Danxuan Koukang Alleviates Arecoline Induced Oral Mucosal Lesions: Network Pharmacology and the Combined Ultra-High Performance Liquid Chromatography (UPLC) and Mass Spectrometry (MS).

Arecoline is one of the main toxic components of arecoline to cause oral mucosal lesions or canceration, which seriously affects the survival and life quality of patients. This study analyzed the mechanism of Jiawei Danxuan Koukang (JDK) in alleviating arecoline induced oral mucosal lesions, to provide new insights for the treatment of oral submucosal fibrosis (OSF) or cancerosis. Metabolomics was applied to analyze the composition of JDK and serum metabolites. The active ingredients of JDK were analyzed by the combined ultra-high performance liquid chromatography and mass spectrometry. The target network of JDK, metabolites and OSF was analyzed by network pharmacology, and molecular docking. Oral mucosal lesions and fibrosis were analyzed by HE and Masson staining. Cell differentiation, proliferation and apoptosis were detected. The expressions of α-SMA, Collagen I, Vimentin, Snail, E-cadherin, AR and NOTCH1 were detected by Western blot. Arecoline induced the gradual atrophy and thinning of rat oral mucosal, collagen accumulation, the increase expressions of fibrosis-related proteins and Th17/Treg ratio. JDK inhibited arecoline-induced oral mucosal lesions and inflammatory infiltration. Arecoline induced changes of serum metabolites in Aminoacyl-tRNA biosynthesis, Alanine, aspartate and glutamate metabolism and Arginine biosynthesis pathways, which were reversed by M-JDK. Quercetin and AR were the active ingredients and key targets of JDK, metabolites and OSF interaction. Arecoline promoted the expression of AR protein, and the proliferation of oral fibroblasts. Quercetin inhibited the effect of arecoline on oral fibroblasts, but was reversed by AR overexpression. Arecoline induced NOTCH1 expression in CAL27 and SCC-25 cells, and promoted cell proliferation, but was reversed by M-JDK or quercetin. JDK improved the arecoline-induced OSF and serum metabolite functional pathway. Quercetin targeted AR protein to improve arecoline-induced OSF. JDK and quercetin inhibited arecoline-induced NOTCH1 protein expression in CAL27 and SCC-25 cells to play an anti-oral cancer role.

Proteomic Profiles and Protein Network Analysis of Primary Human Leukocytes Revealed Possible Clearance Biomarkers for Staphylococcus aureus Infection.

Staphylococcus aureus is a serious pathogen that can survive within host cells after a typical course of treatment completion, leading to chronic infection. Knowledge of host proteomic patterns after clearance of this pathogen from cells is limited. Here, we looked for S. aureus clearance biomarkers produced by in vitro-infected leukocytes. Extracellular proteins from primary human leukocytes infected with S. aureus ATCC 25923 were investigated as possible treatment-monitoring clearance biomarkers by applying a proteomics approach combining liquid chromatography with tandem mass spectrometry (LC-MS/MS) and protein interaction network analysis. It was found that the expression patterns of proteins secreted by S. aureus-infected leukocytes differed among stages of infection. Proteomic profiles showed that an ATPase, aminophospholipid transporter-like, Class I, type 8A, member 2 (ATP8A2) was expressed in the clearance stage and was not detected at any earlier stage or in uninfected controls. Protein network analysis showed that TERF2 (telomeric repeat-binding factor 2), ZNF440 (zinc finger protein 440), and PPP1R14A (phosphatase 1 regulatory subunit 14A) were up-regulated, while GLE1, an essential RNA-export mediator, was suppressed in both infection and clearance stages, suggesting their potential roles in S. aureus infection and clearance. These findings are the first to report that the ATP8A2 has potential as a clearance biomarker for S. aureus infection.

Fingerprinting of quinoa grain protein extracts by liquid chromatography with spectrophotometric detection for chemometrics discrimination

Quinoa (Chenopodium quinoa Willd.) grain is gaining great popularity worldwide because it is a rich source of nutrients, bioactive compounds, complete essential amino acids, and high-quality proteins. The demand for quinoa-based products is on the rise, which makes them prone to adulteration with less expensive cereals. In this study, we described a rapid and simple procedure for fingerprinting of quinoa grain protein extracts based on the combination of liquid chromatography with ultraviolet absorption diode array detection (LC-UV-DAD) and chemometrics. First, we developed a novel LC-UV-DAD method to obtain distinctive multiwavelength chromatographic profiles of protein extracts from various commercial quinoa grains, which encompass different quinoa varieties sold as black, red, white (from Peru), and royal (white from Bolivia). Then, the components of the LC-UV-DAD fingerprints were deconvoluted by multivariate curve resolution alternating least squares (MCR-ALS), and principal component analysis (PCA) followed by partial least squares discriminant analysis (PLS-DA) were applied to efficiently discriminate the commercial quinoa grains according to their differential composition. The chemometrics-assisted LC-UV-DAD fingerprinting methodology demonstrated its potential to rapidly and reliably discriminate quinoa grains according to the differential composition of their protein extracts and it may be applied in food quality and food fraud control.

Improving the removal of losartan, irbesartan and their transformation products through in situ produced hydrogen peroxide in electrochemical oxidation processes

The degradation of losartan (LST) and irbesartan (IBT) has been studied in an electrochemical cell composed of a boron-doped diamond (BDD) anode and a carbonaceous cathode made of reticulated vitreous carbon. The in situ production of hydrogen peroxide (H2O2) was observed at the cathode modified with two types of carbon black (CB) materials; XC72 and XCmax22. The most efficient H2O2 production was attained at the cathode made with XCmax22 in a mass ratio of 1/4 to PTFE (i.e., PTFE/CB). Overall, XCmax22 outperformed XC72 producing almost twice amount of H2O2 and reaching a current efficiency up to 93 %. Furthermore, the in situ produced H2O2 significantly enhanced the electro-oxidation rate of LST and IBT achieving an almost sixfold faster removal of both compounds with 10 mg L−1 of initial concentration of each compound completely removed in 10 min. In addition, the effect of water matrix was also analyzed at low initial concentration of the compounds (500 ng L−1). The degradation of the compounds followed pseudo first order kinetics achieving complete removal of 500 ng L−1 of both compounds in 30 min. Using ultra-high performance liquid chromatography in combination with high-resolution mass spectrometry (UHPLC-HRMS), transformation products of LST and IBT were identified, degradation pathways were proposed and their toxicity was assessed. These results offer an energy- and cost-effective solution for the treatment of recalcitrant organic micropollutants while also providing a pathway for the conversion and storage of excess electrical energy in the form of chemical energy (i.e., H2O2).

A combined liquid chromatography – trapped ion mobility – tandem high-resolution mass spectrometry and multivariate analysis approach for the determination of enzymatic reactivity descriptors in biomass hydrolysates

Intermediate products such as oxygenated compounds may interfere with bioconversion kinetics of lignocellulosic biomass into bioethanol. This work presents a multidimensional approach, based on liquid chromatography (LC), trapped ion mobility spectrometry (TIMS), tandem high-resolution mass spectrometry (HRMS/MS), and multivariate analysis, for the identification of enzymatic reactivity descriptors in 22 industrial biomass samples, called hydrolysates. The first part of the study is dedicated to the improvement of the chemical diversity assessment of the hydrolysates through an original three-dimensional Van Krevelen diagram displaying the double bond equivalent (DBE) as third dimension. In a second part, the evaluation of data by multivariate data analysis allowed the discrimination of sample according to the biomass type and the level of enzymatic reactivity. In the last part, a potential descriptor of low enzymatic reactivity was selected and used in a case study. An in-depth structural analysis was performed on the feature annotated as carbohydrate derivative. Considering the intricate fragmentation spectrum exhibited by the selected feature, trapped ion mobility was employed to enhance separation prior to the HRMS/MS experiments. This final step improved data interpretation and increased the identification confidence level leading to the characterization of xylotriose, 3,5-dimethoxy-4-hydroxybenzaldehyde and 4-hydroxy-3-methoxy-cinnamaldehyde. This is the first study to present an untargeted multidimensional approach for the identification of enzymatic hydrolysis inhibitors in industrial hydrolysate samples.

Absorption, Metabolism, and Excretion of [14C]-Tolebrutinib After Oral Administration in Humans, Contribution of the Metabolites to Pharmacological Activity.

Tolebrutinib is a covalent inhibitor of Bruton's tyrosine kinase, an enzyme expressed in B lymphocytes and myeloid cells including microglia, which are thought to be major drivers of inflammation in multiple sclerosis. This excretion balance and metabolism study evaluated the metabolite profile of tolebrutinib in healthy male volunteers. Six healthy volunteers received a 60-mg oral dose of [14C]-tolebrutinib, and metabolite profiling of 14C-labeled metabolites was performed using a combination of liquid chromatography, mass spectrometry, and radioactivity assay methods. Tolebrutinib was rapidly and completely absorbed from the gastrointestinal tract, followed by rapid and extensive metabolism. Excretion via feces was the major elimination pathway of the administered radioactivity (78%). Tolebrutinib was highly metabolized, with 19 metabolites identified in human plasma. Phase 1 biotransformations were primarily responsible for the circulating metabolites in plasma. Seven metabolites that achieved exposure in plasma similar to or higher than the parent compound were characterized biochemically for inhibition of Bruton's tyrosine kinase activity. Metabolite M8 exceeded the exposure threshold of 10% (18%) of the total radioactivity but had little if any pharmacological activity. Metabolite M2 (4% of circulating radioactivity) retained the ability to irreversibly and potently inhibit Bruton's tyrosine kinase in vitro, similar to the parent compound. Tolebrutinib and metabolite M2 had short (3.5-h) half-lives but durable pharmacodynamic effects as expected for an irreversible antagonist. Tolebrutinib was extensively metabolized to multiple metabolites. The hydroxylated metabolite M2 demonstrated similar inhibitory potency toward Bruton's tyrosine kinase as the parent compound. Both tolebrutinib and metabolite M2 likely contributed to pharmacological activity in vivo.

Profiling of the Polyphenol Content of Honey from Different Geographical Origins in the United States.

The presence of phenolic compounds in honey can serve as potential authenticity markers for honey's botanical or geographical origins. The composition and properties of honey can vary greatly depending on the floral and geographical origins. This study focuses on identifying the specific markers that can distinguish honey based on their geographical areas in the United States. The main approach presented in this study to identify the geographic origins of honey involves chemometric methods combined with phenolic compound fingerprinting. Sample clean-up and phenolic compound extraction was carried out using solid phase extraction (SPE). Reversed phase liquid chromatography in combination with tandem mass spectrometry were utilized for the separation of the compounds. The honey physicochemical qualities were predominantly determined via spectrophotometric methods. Multivariate statistical tools such as principal component analysis (PCA), analysis of variance (ANOVA), and partial-least squares discriminant analysis (PLS-DA) were employed as both classification and feature selection tools. Overall, the present study was able to identify the presence of 12 potential markers to differentiate the honey's geographical origins. The total phenolic content ranged from 81.6 to 105.7 mg GAE/100 g corresponding to honey from Colorado and Washington, respectively (GAE: gallic acid equivalents). The regression analysis shows a tendency for the total phenolic content of honey to increase as the color of honey increases. The most important result obtained in this study is the demonstration that the geographical origin of honey plays a critical role in predicting the physical properties and phenolic composition of honey.

Theogallin-to-Gallic-Acid Ratio as a Potential Biomarker of Pu-Erh Teas

There are two types of Pu-erh tea available on the world market: Raw and Ripe. It is not difficult to tell them apart if the Raw version is relatively young. Researchers have already developed various tools to identify Pu-erh teas. However, they are quite complicated and require advanced statistical analyses. In addition, they are characterized by different levels of accuracy. The aim of the work was to identify relationships or differences that would easily give specific results for identifying types of Pu-erh tea. The content of selected methylxanthines was determined by high-performance liquid chromatography (HPLC) on an Agilent 1200 chromatograph with a UV-VIS diode array detector. The total analysis time was 28 min. A combination of liquid chromatography and a triple quadrupole mass spectrophotometer was used to identify gallic acid and theogallin in the analyzed samples. A multivariate cluster analysis was used to compare the results for single samples, and its results were presented in horizontal hierarchical tree plots. The quantitative determination showed that theophylline is present only in Ripe Pu-erh teas. In addition, it was shown that the ratio of theogallin to gallic acid can be an effective tool to verify the authenticity of Pu-erh varieties.