Phytochemical Screening Using LC-MS to Study Antioxidant and Toxicity Potential of Methanolic Extracts of Atraphaxis pyrifolia Bunge.

Atraphaxis pyrifolia, a native medicinal plant of Central Asia, has a long history of traditional medicinal use; however, scientific research on its phytochemical and biological properties remains scarce. This paper aims to elucidate its chemical profile and assess its pharmacological potential through a comprehensive investigation of the phytochemical composition of stems and leaves using Liquid Chromatography-Mass Spectrometry (LC-MS), in conjunction with the assessment of its antioxidant (DPPH and ABTS) and cytotoxicity test on Artemia salina. Predominantly, glycosylated flavonoids were detected in stems and leaves extracts, notably including 8-Acetoxy-3',4',5,5'-tetrahydroxy-7-methoxy-3-α-L-rhamno-pyranosyloxyflavone, pyrifolin, and dehydroxypyrifolin. While the latter compound is exclusive to A. pyrifolia, the former compounds serve as shared chemical markers with other Atraphaxis species. The methanolic extracts of A. pyrifolia leaves exhibited significant antioxidant capacity without toxicity against Artemia salina. This study contributes to current research through providing valuable insights into the chemical diversity and potential medicinal properties of this plant species.

In-situ stabilized lipase in calcium carbonate microparticles for activation in solvent-free transesterification for biodiesel production.

Biodiesel serves as a crucial biofuel alternative to petroleum-based diesel fuels, achieved through enzymatic transesterification of oil substrates. This study aims to investigate stabilized lipase (LP) within calcium carbonate (CaCO3) microparticles as a catalyst for solvent-free transesterification in biodiesel synthesis. The specific hydrolysis activity of the in-situ immobilized LP was 66% of that of free LP. However, the specific transesterification activity of immobilized LP in the solvent-free phase for biodiesel production was 2.29 times higher than that of free LP. These results suggest that the interfacial activation of LP molecules is facilitated by the inorganic CaCO3 environment. The immobilized LP demonstrated higher biodiesel production levels with superior stability compared to free LP, particularly regarding methanol molar ratio and temperature. To the best of our knowledge, there are no previous reports on the in-situ immobilization of LP in a CaCO3 carrier without any crosslinker as an interfacial-activated biocatalyst for biodiesel production.

Hydrogen/Deuterium Exchange Reaction Rate of Cytochrome c Determined by Droplet Collision Atmospheric Pressure Infrared Laser Ablation Mass Spectrometry.

The hydrogen/deuterium (H/D) exchange rate is an optimal measure for studying the structures and dynamics of hydrogen bonding systems, as it reflects the molecular contact environment and the strength of the hydrogen bonds. A method for rapid measurement of the H/D exchange reaction rates is required to examine the intermolecular environments of molecules in solutions. We developed a droplet collision atmospheric pressure infrared laser ablation mass spectrometry technique for this purpose. We obtained the H/D exchange reaction rate of cytochrome c in a methanol/H2O·D2O solution. We revealed that the first hydration shell of the cytochrome c molecule hinders the penetration of D2O to the surface of the molecule from the rates, which provides a novel method to investigate solution structures by a mass-spectrometric method. The droplet-collision mass spectrometry method developed in the present study can be extended to research on the molecular interactions in solutions, such as the mutual interactions of protein molecules, which are of importance in living cells.

Impact of mobile and stationary phases on siRNA duplex stability in liquid chromatography.

Nucleic acid duplexes are typically analyzed in non-denaturing conditions. Melting temperature (Tm) is the property used to measure duplex stability; however, it is not known how the chromatographic conditions and mobile phase composition affect the duplex stability. We employed differential scanning calorimetry (DSC) method to measure the melting temperature of chemically modified silencing RNA duplex (21 base pairs, 0.15 mM duplex concentration) in mobile phases commonly used in reversed-phase, ion-pair reversed-phase, size exclusion and hydrophilic interaction chromatography. We investigated mobile phases consisting of ammonium acetate, alkylammonium ion-pairing reagents, alkali-ion chlorides, magnesium chloride, and additives including methanol, ethanol, acetonitrile and hexafluoroisopropanol. Increasing buffer concentration enhanced the duplex stability (Tm was 67.1 - 78.2 °C for 10-100 mM [Na+] concentration). The melting temperature decreases with the increase in cation size (70.2 °C in 10 mM [Li+], 68.1 °C in 10 mM [NH4+], 65.6 °C in 10 mM [Cs+], and 56.6 °C in 10 mM [triethylammonium+] solutions). Inclusion of 20 % of organic solvent in buffer reduced the melting temperature by 1-3 °C, and denaturation power increases in the order MeOH

Determination of specific surface area of biomass activated carbon vial headspace gas chromatography technique.

This paper introduces a method for determining the specific surface area (SSA) of biomass activated carbon (BAC) using a tracer-based headspace gas chromatography (HS-GC) technique. The method relies on the adsorption equilibrium of methanol on BAC samples at elevated temperature. A mathematical model allows for the calculation of SSA from the methanol signal obtained during the headspace analysis. The results demonstrate high precision (relative standard deviation < 2.44%) and strong accuracy (correlation with the conventional BET-N2 adsorption method, R² = 0.986). This method offers several advantages over traditional techniques, including ease of operation, significant time efficiency, and the the ability to perform batch determinations of SSA, as multiple samples can be processed simultaneously during the phase equilibrium step.

Novel multiple extraction thermal desorption approach prior to gas chromatography for the determination of residual solvents applied to modified cellulose.

In this work, multiple extraction thermal desorption (METD), as a sample introduction method for GC, was developed. This technique was used for the determination of residual solvents (RS) in modified cellulose, because it is practically impossible to dissolve or distribute it uniformly in water and common organic solvents. Moreover, METD facilitates the optimization of the desorption time and it is more sensitive to quantify trace level volatiles in insoluble material, compared to direct dynamic desorption (DDD). In addition, METD provides diagnostic information about the sample-sorbent interaction. Three solvents (methanol, ethanol and tert-butanol) were determined in two types of modified cellulose (dialdehyde cellulose (DAC) and DAC-ethylenediamine (DAC-EDA)). It was shown that good linearity over a wide concentration range was achieved. The limits of detection (LOD) and limits of quantification (LOQ) for the different solvents ranged from 0.1 to 0.3 µg and from 0.3 to 0.9 µg per tube, respectively. Accuracy of the METD method was verified by using an alternative method based on the decomposition of the modified celluloses by Trichoderma reesei cellulase, followed by headspace-trap-GC (HS-trap-GC). The results obtained from the two validated methods were found to be similar (relative deviation < 17.0 %). However, the developed METD-GC method is preferable for the analysis of RS in modified cellulose since it does not require sample pretreatment and possesses higher sensitivity.

Toxicological profiling of methanolic seed extract of Abutilon indicum (L.) Sweet: in-vitro and in-vivo analysis.

ETHNOPHARMACOLOGICAL RELEVANCE: Abutilon indicum, a shrub of the Malvaceae family, is found abundantly in tropical countries like India. A. indicum is widely used for its high medicinal properties. Traditionally, A. indicum seed powder is consumed to treat piles, constipation, chronic cystitis, gonorrhea, gleet, and pregnancy-related problems. Despite having numerous medicinal properties and widespread traditional use of A. indicum seeds, scientific validation, and toxicity studies have yet to be documented. AIMS OF THE STUDY: The primary objective of this study is to conduct a comprehensive study on phytochemical profiling, in-vitro cytotoxicity, mutagenicity, and in-vivo acute and sub-acute toxicity, and genotoxicity on animal models of methanolic extract of A. indicum seed (MAS). MATERIALS AND METHODS: The qualitative analysis of MAS was explored through FTIR and HR LC-MS. For in-vitro cytotoxicity, the HEK-293 cell line was used, and the TA100 (Staphylococcus typhimurium) bacterial strain was used for the Ames mutagenicity test. A single oral dose of 250, 500, 1000, or 2000 mg/kg body weight of MAS was given to each male and female rat for acute toxicity study and observed for 14 days for any toxicity signs. In the sub-acute toxicity study, 250, 500, or 1000 mg/kg body weight of MAS was administered orally to each rat for 28 days. The experimental animals were weighed weekly, and general behavior was monitored regularly. After 28 days of the experiment, the rats were sacrificed, and different serum biochemical, hematological, and histological analyses were performed. The blood samples of different doses of MAS were used for genotoxicity study through comet assay. RESULTS: FTIR analysis found different functional groups, which indicated the presence of phenolics, flavonoids, and alkaloids. HR LC-MS analysis depicts several components with different biological functions. The cell cytotoxicity and Ames mutagenicity results showed minimal toxicity and mutagenicity up to a certain dose. The acute toxicity study conducted in Wistar albino rats demonstrated zero mortality among the animals, and the LD50 value for seed extract was determined to be 2000 mg/kg body weight. Sub-acute toxicity assessments indicated that the administration of seed extract resulted in no adverse effects at dosages of 250 and 500 mg/kg body weight. However, at higher doses, specifically 1000 mg/kg body weight, the liver of the experimental rats exhibited some toxic effects. In the genotoxicity study, minimal DNA damage was found in 250 and 500 mg/kg doses, respectively, but slightly greater DNA damage was found in 1000 mg/kg doses in both male and female rats. CONCLUSIONS: The consumption of A. indicum seed powder is deemed safe; however, doses exceeding 500 mg/kg body weight may raise concerns regarding use. These findings pave the path for the creation of innovative medicines with improved efficacy and safety profiles.

Exploring carbon-based Cu-ZnO catalyst and substitutes for enhanced selective methanol production from CO2: An integrated experimental and computational study.

Methanol, produced through the hydrogenation of carbon dioxide, is an essential intermediate compound that plays a crucial function in the production of various organic chemicals. Enhancing the design of copper-containing catalysts for the transformation of CO2 to methanol is a popular strategy in scientific literature, although challenges persist in advancing the efficiency of carbon dioxide transformation and the selectivity of methanol production. This research aims at creating CuZnO-M/rGO (M = Mg, Mn, and Cr) catalysts using an efficient method for selectively converting CO2 to methanol. By optimizing the operational parameters of this system, methanol productivity and CO2 conversion efficiency are enhanced. Under optimal conditions, a CO2 conversion rate of 23.5%, methanol selectivity of 90%, and a space-time yield of 0.47 gMeOH.gcat-1.h-1 were achieved with the CuZnO-MgO (5)/rGO catalyst. These levels were maintained over a 100-h period, demonstrating the stability of the catalyst system. These findings are highly consistent with the density functional theory (DFT) calculations, revealing that the CuZnO-MgO (5)/rGO catalyst possesses a -0.35 eV adsorption energy for CO2 and a favorable reaction pathway with the overpotential of 1.16 V towards methanol production emphasizing the high conversion and selectivity obtained.

Cytotoxic Activity of Lepidium virginicum L. Methanolic Extract on Human Colorectal Cancer Cells, Caco-2, through p53-Mediated Apoptosis.

Colorectal cancer (CRC) is the third most common type of cancer worldwide. Its treatment options have had a limited impact on cancer remission prognosis. Therefore, there is an ongoing need to discover novel anti-cancer agents. Medicinal plants have gained recognition as a source of anti-cancer bioactive compounds. Recently, ethanolic extract of L. virginicum stems ameliorated dinitrobenzene sulfonic acid (DNBS)-induced colitis by modulating the intestinal immune response. However, no scientific study has demonstrated this potential cytotoxic impact on colon cancer cells. The objective of this study was to evaluate the cytotoxic effect of the methanolic extract of L. virginicum (ELv) on a human colorectal adenocarcinoma cell line (Caco-2) and to identify and quantify the phenolic compounds present in ELv extracts by liquid chromatography-mass spectrometry analysis. The cytotoxic activity was assessed using cell viability assays by reduction in the compound 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH). MTT and LDH assays revealed that the ELv decreases cell viability in the Caco-2 cell line in a concentration-dependent manner. Cell death was a result of DNA fragmentation and p53-mediated apoptosis. Eight phenolic acids and five flavonoids were identified and quantified in the stems. In conclusion, our findings demonstrate that the extract of L. virginicum possesses cytotoxic properties on Caco-2 cell line, suggesting that it could be a potential source of new drugs against CRC.

Investigation of Enzyme Immobilization and Clogging Mechanisms in the Enzymatic Synthesis of Amoxicillin.

This study investigated the blocking mechanism of immobilized penicillin G acylase (PGA) during the enzymatic synthesis of amoxicillin. Laboratory observations revealed that the primary cause of clogging was the crystallization of the substrate and product on the enzyme surface. Adjusting key parameters can significantly reduce clogging and improve catalytic efficiency. Methanol can decrease enzyme activity, but isopropyl alcohol cleaners can effectively remove clogs and protect enzyme activity. These findings provide an experimental foundation for optimizing the PGA immobilization process, which is crucial for achieving high efficiency and sustainability in industrial production.

Assessing the Efficacy of Protease Inactivation for the Preservation of Bioactive Amphibian Skin Peptides.

The skin of amphibians is a rich source of peptides with a wide range of biological activities. They are stored in secretory granules in an inactive form. Upon stimulation, they are secreted together with proteases into the skin. Once activated, they rapidly exert their biological effects, including fighting microorganisms and predators, while their excess is immediately destroyed by the released proteases. To keep bioactive peptides in their initial form, it is necessary to inhibit these enzymes. Several inhibitors for this purpose have previously been mentioned; however, there has not been any reliable comparison of their efficiency so far. Here, we studied the efficiency of methanol and hydrochloric and formic acids, as well as phenylmethylsulfonyl fluoride, in the inhibition of nine frog peptides with the known sequence, belonging to five families in the secretion of Pelophylax esculentus. The results demonstrated that methanol had the highest inhibitory efficiency, while phenylmethylsulfonyl fluoride was the least efficient, probably due to its instability in aqueous media. Possible cleavages between certain amino acid residues in the sequence were established for each of the inhibitors. These results may be helpful for future studies on the nature of proteases and on prediction of the possible cleavage sites in novel peptides.

Fundamental investigation of impact of water and TFA additions in peptide sub/supercritical fluid separations.

The retention of three peptides was studied under analytical and overloaded conditions at different concentrations of trifluoroacetic acid (TFA) and water added to the co-solvent methanol (MeOH). Four columns with different stationary phase properties, i.e., silica, diol, 2-ethylpyridine and cyanopropyl (CN) columns, were evaluated in this investigation. The overall aim was to get a deeper understanding on how column chemistry as well as water and TFA in the co-solvent affect the analytical and overloaded elution profiles using multivariate design of experiments and adsorption measurements of co-solvent components. Multivariate experimental design modeling indicated that water had on average around five times higher effect on the retention than the addition of TFA. The results also showed that the retention increases with the addition of TFA and water to the co-solvent on all columns except the CN column, on which the retention decreased. When examining the effect of adding water to the co-solvent, evidence of a hydrophilic interaction liquid chromatography (HILIC)-like retention mechanism was found on the three other columns with more polar stationary phases. However, on the CN column water acted as an additive, decreasing the retention due to competition with the peptide for available adsorption surface. Adsorption isotherm measurements of the polar solvent MeOH showed that MeOH adsorbs much weaker on the CN column than on the other columns. Addition of TFA and water to the co-solvent substantially sharpened the elution profiles under both overloaded and analytical conditions. Adding a small amount of TFA (from 0 % to 0.05 %) to the co-solvent substantially improved the peak shape of the elution profiles, while further addition (from 0.05 % to 0.15 %) had only a minor effect on the elution profile shape. The reduced retention on the CN column could not be explained by TFA adsorption, which was very weak on all studied columns (retention factor, 0.05-0.15). One could therefore speculate that the ion-pairing complex formed between the peptide and TFA in the mobile phase, reduce the retention due to its reduced polarity. On the other columns displaying HILIC-like properties, the TFA probably just decreased the pH of the mobile phase, thereby promoting the partitioning of the peptide into the water-rich layer. Finally, peak deformation due to diluent-eluent mismatch was observed under overloaded conditions. This was most severe in the cases where MeOH adsorption to the stationary phase was strong and the peptides were only mildly retained. Adding 1,4-dioxan to the diluent resolved this issue.

Antibacterial Efficacy and Characterization of Silver Nanoparticles Synthesized via Methanolic Extract of Fomes fomentarius L. Fr.

Green synthesis employs environmentally friendly, biodegradable substances for the production of nanomaterials. This study aims to develop an innovative method for synthesizing silver nanoparticles (AgNPs) using a methanolic extract of Fomes fomentarius L. Fr. as the reducing agent and to assess the potential antibacterial properties of the resulting nanoparticles. The successful synthesis of AgNPs was confirmed through characterization techniques such as UV-visible (UV-Vis) spectrophotometry, Fourier-transform infrared spectroscopy (FT-IR), and powder X-ray diffraction (PXRD). The UV-Vis analysis revealed an absorption peak at 423 nm, while FT-IR identified key phytochemical compounds involved in the reduction process. PXRD analysis indicated a face-centered cubic (fcc) structure with prominent peaks observed at 2θ = 38°, 44.6°, 64.6°, and 78°, confirming the crystalline nature of the AgNPs, with a crystallite diameter of approximately 24 nm, consistent with TEM analysis. The synthesized AgNPs demonstrated significant antibacterial activity, particularly against S. aureus, with higher efficacy against gram-positive bacteria.

Biodiesel Production from Waste Cooking Oil Using Recombinant Escherichia coli Cells Immobilized into Fe3O4-Chitosan Magnetic Microspheres.

Developing reusable and easy-to-operate biocatalysts is of significant interest in biodiesel production. Here, magnetic whole-cell catalysts constructed through immobilizing recombinant Escherichia coli cells (containing MAS1 lipase) into Fe3O4-chitosan magnetic microspheres (termed MWCC@MAS1) were used for fatty acid methyl ester (FAME) production from waste cooking oil (WCO). During the preparation process of immobilized cells, the effects of chitosan concentration and cell concentration on their activity and activity recovery were investigated. Optimal immobilization was achieved with 3% (w/v) chitosan solution and 10 mg wet cell/mL cell suspension. Magnetic immobilization endowed the whole-cell catalysts with superparamagnetism and improved their methanol tolerance, enhancing the recyclability of the biocatalysts. Additionally, we studied the effects of catalyst loading, water content, methanol content, and reaction temperature on FAME yield, optimizing these parameters using response surface methodology and Box-Behnken design. An experimental FAME yield of 89.19% was gained under the optimized conditions (3.9 wt% catalyst loading, 22.3% (v/w) water content, 23.0% (v/w) methanol content, and 32 °C) for 48 h. MWCC@MAS1 demonstrated superior recyclability compared to its whole-cell form, maintaining about 86% of its initial productivity after 10 cycles, whereas the whole-cell form lost nearly half after just five cycles. These results suggest that MWCC@MAS1 has great potential for the industrial production of biodiesel.

Down-regulation of NF-κB signalling by methanolic extract of Viola odorata (L.) attenuated in vivo inflammatory and angiogenic responses.

Intractable inflammation plays a key role in the progression of autoimmune diseases such as rheumatoid arthritis. Oedema and angiogenesis are the hall marks of chronic inflammation. The current study was aimed to investigate the pharmacological effects of the methanolic extract of Viola odorata (Vo.Me) on inflammation induced oedema and angiogenesis, and to identify the active principles and explore the molecular mechanisms thereof. Various models of inflammation were utilized in rats, including carrageenan- and histamine-induced acute oedema, as well as chronic models of Complete Freund's Adjuvant (CFA)-induced arthritis and cotton pellet-induced granuloma. Anti-angiogenic activity was evaluated by CAM assay followed by quantification of phytoconstituents through HPLC. Effect of Vo.Me  treatment on the expression of various mediators (PGE-2 and NO) and genes (IL-1ß, TNF-α, NF-κB, and COX-2) were explored by qPCR and ELISA assays. HPLC analysis showed the presence of quercetin, chlorogenic acid, gallic acid, benzoic acid, m-coumaric acid, p-coumaric acid, synergic acid, caffeic acid, vanillic acid, sinapic acid, and cinnamic acid in Vo.Me. Significant dose-dependent inhibition of rats' paw oedema was observed in the Vo.Me administered groups (p < 0.05) in both acute and chronic inflammatory models. Moreover, at a dosage of 500 mg/kg, Vo.Me exhibited a comparable anti-inflammatory effect to indomethacin (p > 0.05). Additionally, Vo.Me demonstrated a remarkable anti-granulomatous activity. Histopathological findings demonstrated amelioration of inflammation in animal paws which were treated with Vo.Me and indomethacin. CAM assay also displayed significant inhibitory effect of Vo.Me on the blood vasculature growth. Vo.Me treatment also caused relatively less gastric irritation and hepatic damage as compared to indomethacin. At a molecular level, the down-regulation of NF-κB signalling  leading to the decreased activation of pro-inflammatory mediators (such as IL-1ß, TNF-α, and COX-2) and their downstream molecules including prostaglandin E-2 (PGE-2) and nitric oxide (NO), is suggested to be responsible for these diverse anti-inflammatory effects. These findings confirmed the promising anti-inflammatory and anti-angiogenic activities of Vo.Me, which warrant bench-to-bedside translational studies to assess its safety and suitability for clinical usage.

Geraniin from the methanol extract of Pilea mongolica suppresses LPS-induced inflammatory responses by inhibiting IRAK4/MAPKs/NF-κB/AP-1 pathway in HaCaT cells.

The skin acts as a vital barrier, shielding the body from external threats that can trigger dryness, itching, and inflammation. Pilea mongolica, a traditional Chinese medicinal herb, holds promise for various ailments, yet its anti-inflammatory properties remain understudied. This study aimed to explore the potential anti-inflammatory effects of the methanol extract of P. mongolica (MEPM) and its underlying molecular mechanisms and active compounds in LPS-stimulated human keratinocytes. MEPM treatment, at concentrations without cytotoxicity, significantly decreased NO productions and the iNOS, IL-6, IL-1ß, and TNF-α levels in LPS-induced HaCaT cells. Moreover, MEPM suppressed IRAK4 expression and phosphorylation of JNK, ERK, p38, p65, and c-Jun, suggesting that the anti-inflammatory effects of MEPM result from the inhibition of IRAK4/MAPK/NF-κB/AP-1 signaling pathway. Through LC/MS/MS analysis, 30 compounds and 24 compounds were estimated in negative and positive modes, respectively, including various anti-inflammatory compounds, such as corilagin and geraniin. Through HPLC analysis, geraniin was found to be present in MEPM at a concentration of 18.87 mg/g. Similar to MEPM, geraniin reduced iNOS mRNA expression and inhibited NO synthesis. It also decreased mRNA and protein levels of inflammatory cytokines, including IL-6 and TNF-α, and inhibited IRAK4 expression and the phosphorylation of MAPKs, NF-κB, and AP-1 pathways. Therefore, it can be inferred that the anti-inflammatory effects of MEPM are attributable to geraniin. Thus, MEPM and its active compound geraniin are potential candidates for use in natural functional cosmetics.

In vitro and in silico evaluation of bioactivities and chemical composition of the aerial parts of Anchusa officinalis L. methanol extract.

The main objective of the study is to evaluate the antioxidant, anticancer, and antimicrobial activities of Anchusa officinalis L. in vitro and in silico. The dried aerial parts of A. officinalis L. were extracted with methanol. Total phenolic and flavonoid content was analyzed. Antioxidant and antimicrobial effects were tested against both gram-positive and gram-negative bacteria. Gas chromatography-mass spectrometry analysis revealed the presence of 10 phytochemical compounds, and cyclobutane (26.07%) was identified as the major photochemical compound. The methanol extract exhibited the maximum amount of total phenolic content (118.24 ± 4.42 mg QE/g dry weight of the dry extract) (R2 = 0.994) and the total flavonoid content was 94 ± 2.34 mg QE/g dry weight of the dry extract (R2 = 0.999). The IC50 value for 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid was 107.12 ± 3.42 µg/mL, and it was high for 1,1-diphenyl-2-picryl hydrazyl (123.94 ± 2.31 µg/mL). The IC50 value was 72.49 ± 3.14 against HepG2 cell lines, and a decreased value was obtained (102.54 ± 4.17 g/mL) against MCF-7 cell lines. The methanol extract increased the expression of caspase mRNA and Bax mRNA levels when compared to the control experiment (p < .05). The conclusions, A. officinalis L. aerial parts extract exhibited antibacterial, antifungal, and antioxidant activities.

Dependency of fentanyl analogue protomer ratios on solvent conditions as measured by ion mobility-mass spectrometry.

Recently, our group has shown that fentanyl and many of its analogues form prototropic isomers ("protomers") during electrospray ionization. These different protomers can be resolved using ion mobility spectrometry and annotated using mobility-aligned tandem mass spectrometry fragmentation. However, their formation and the extent to which experimental variables contribute to their relative ratio remain poorly understood. In the present study, we systematically investigated the effects of mixtures of common chromatographic solvents (water, methanol, and acetonitrile) and pH on the ratio of previously observed protomers for 23 fentanyl analogues. Interestingly, these ratios (N-piperidine protonation vs. secondary amine/O = protonation) decreased significantly for many analogues (e.g., despropionyl ortho-, meta-, and para-methyl fentanyl), increased significantly for others (e.g., cis-isofentanyl), and remained relatively constant for the others as solvent conditions changed from 100% organic solvent (methanol or acetonitrile) to 100% water. Interestingly, pH also had significant effects on this ratio, causing the change in ratio to switch in many cases. Lastly, increasing conditions to pH ≥ 4.0 also prompted the appearance of new mobility peaks for ortho- and para-methyl acetyl fentanyl, where all previous studies had only showed one single distribution. Because these ratios have promise to be used qualitatively for identification of these (and emerging) fentanyl analogues, understanding how various conditions (i.e., mobile phase selection and/or chromatographic gradient) affect their ratios is critically important to the development of advanced ion mobility and mass spectrometry methodologies to identify fentanyl analogues.

Preparative separation of the constituents from Ginkgo biloba L. leaves by a combination of multi-stage solvent extraction and countercurrent chromatography.

In this study, we employed a combination approach for the preparative separation of constituents from Ginkgo biloba L. leaves. It involved multi-stage solvent extractions utilizing two-phase multi-solvent systems and countercurrent chromatography (CCC) separations using three different solvent systems. The n-heptane/ethyl acetate/water (1:1:2, v/v) and n-heptane/ethyl acetate/methanol/water (HepEMWat, 7:3:7:3, v/v) solvent systems were screened out as extraction systems. The polarities of the upper and lower phases in the multi-solvent systems were adjustable, enabling the effectively segmented separation of complex constituents in G. biloba L. The segmented products were subsequently directly utilized as samples and separated using CCC with the solvent systems acetate/n-butanol/water (4:1:5, v/v), HepEMWat (5:5:5:5, v/v), and HepEMWat (9:1:9:1, v/v), respectively. As a result, a total of 11 compounds were successfully isolated and identified from a 2 g methanol extract of G. biloba L through two-stage extraction and three CCC separation processes; among them, nine compounds exhibited high-performance liquid chromatography purity exceeding 85%.

Sustainable methanol production from carbon dioxide: advances, challenges, and future prospects.

The urgent need to address global carbon emissions and promote sustainable energy solutions has led to a growing interest in carbon dioxide (CO2) conversion technologies. Among these, the transformation of CO2 into methanol (MeOH) has gained prominence as an effective mitigation strategy. This review paper provides a comprehensive exploration of recent advances and applications in the direct utilization of CO2 for the synthesis of MeOH, encompassing various aspects from catalysts to market analysis, environmental impact, and future prospects. We begin by introducing the current state of CO2 mitigation strategies, highlighting the significance of carbon recycling through MeOH production. The paper delves into the chemistry and technology behind the conversion of CO2 into MeOH, encompassing key themes such as feedstock selection, material and energy supply, and the various conversion processes, including chemical, electrochemical, photochemical, and photoelectrochemical pathways. An in-depth analysis of heterogeneous and homogeneous catalysts for MeOH synthesis is provided, shedding light on the advantages and drawbacks of each. Furthermore, we explore diverse routes for CO2 hydrogenation into MeOH, emphasizing the technological advances and production processes associated with this sustainable transformation. As MeOH holds a pivotal role in a wide range of chemical applications and emerges as a promising transportation fuel, the paper explores its various chemical uses, transportation, storage, and distribution, as well as the evolving MeOH market. The environmental and energy implications of CO2 conversion to MeOH are discussed, including a thermodynamic analysis of the process and cost and energy evaluations for large-scale catalytic hydrogenation.