Search

A novel and meaningful theoretical model was established with counter-current chromatography based on the elution-extrusion mode for efficient continuous separation. For the experimental verification of the theory, the separation of the binary mixture luteolin/baicalein was studied. The velocity model and volume model of the chromatographic separation behavior of the target compounds in the separation process were given by theoretical analysis. The results showed that this method had obvious advantages in the separation of binary mixtures. In addition, the established model was used to predict and isolate oleuropein from olive leaves. A two-phase solvent system of n-butanol/ethyl acetate/methanol/water (1:19:1:19, v/v/v/v) was chosen for the continuous separation of oleuropein. After optimizing the conditions in this way, a large amount of sample loading was achieved; the volume of injections can reach 48 ml, approximately 35.29% of the volume of the counter-current chromatography column, and oleuropein with a purity of 86.42% was obtained within 80 min. The model provided technical support for the prediction of chromatographic behavior and operating parameters during continuous separation and preparation of counter-current chromatography. It has great application prospects and significance in separation preparation, especially in large-scale industrial preparation.

Recent studies strongly suggest that atorvastatin combination therapy with tangeretin could be beneficial in the treatment of hyperlipidemia. This study aimed to investigate the pharmacokinetic interactions among atorvastatin, its active metabolite 2-hydroxy atorvastatin, and tangeretin after oral administration of atorvastatin with tangeretin in rats. A rapid, selective, and sensitive assay was developed and validated based on ultra-high performance supercritical fluid chromatography-tandem mass spectrometry for the simultaneous measurement of atorvastatin, 2-hydroxy atorvastatin, and tangeretin concentrations in rat plasma. Chromatographic separation of the analytes was conducted on an ACQUITY Torus 1-AA column in gradient elution mode. The mass transition ion pairs were m/z 559.0→440.0 for atorvastatin, m/z 575.2→440.0 for 2-hydroxy atorvastatin, m/z 373.0→358.1 for tangeretin, and m/z 254.8→136.7 for daidzein (internal standard). Calibration curves showed good linear correlations at the following concentration range: 1-400 (r = 0.9952), 1-400 (r = 0.9980), and 3-1200 (r = 0.9945) for atorvastatin, 2-hydroxy atorvastatin, and tangeretin, respectively. The method was fully validated and satisfied the acceptance criteria recommended by the United States Food and Drug Administration. Finally, it was successfully applied in a pharmacokinetic study in rats to evaluate the pharmacokinetic behavior of atorvastatin, 2-hydroxy atorvastatin, and tangeretin.

An active substance of pyrano[3,2-a]phenazine, also called CPUL1, is a synthesized phenazine derivative and displays broad-spectrum anticancer activities. Quantitative assessment of CPUL1 in biological samples has not been well established, hindering pharmaceutical development and application. According to international guidelines, a sensitive and selective liquid chromatography-tandem mass spectrometry method in negative ion mode was developed and validated for quantification of CPUL1 in human plasma, colorectal cancer cell lines, and rat plasma, whereby linearity and accuracy were demonstrated for the range of 1-1000 ng/ml. The validated liquid chromatography-tandem mass spectrometry method was successfully employed in pharmacokinetic studies of CPUL1 in vitro and in vivo. Notably, the cellular pharmacokinetic behavior of CPUL1 varies in colorectal cancer cell lines. Regarding the pharmacokinetic processes in vivo, oral absorption was less effective than an injection, with a bioavailability of 23.66%. CPUL1 was linearly eliminated after a single administration; however, it could accumulate in tissues (heart, liver, spleen, lung, and kidney) after multiple injections. In summary, this study established a capable bioanalytical method for CPUL1 and provided exploratory pharmacokinetic data, paving the way for use of this promising derivative in disease models.

This study analyzed a lipidomic profile of platelets from blood stasis rats by liquid chromatography-tandem mass spectrometry. The blood stasis rat was established by low-dose continuous subcutaneous injection of adrenaline, and the evaluation indexes included hemorheology and platelet aggregation. Principal component analysis and partial least-squares discriminant analysis were used to analyze platelet lipidomics, and p-value 0.05, fold change 1.5, and variable importance plot 2 were used to screen potential biomarkers. Then, the biomarkers were optimized by the receiver operating characteristic curve. Compared with the normal rat, the blood stasis model group's whole blood viscosity and platelet aggregation rate were also significantly increased at different shear rates (p 0.05). Twenty-four potential lipid biomarkers showed significant changes in platelets between the two groups. Among them, six long-chain acylcarnitine components and three sphingosine components showed a consistent downward trend, suggesting that these two kinds of components may play an essential role in the process of platelet aggregation. Liquid chromatography-tandem mass spectrometry-based lipidomics studies provide much information to understand the pathology of platelets in blood stasis.

In this study, magnetic pomelo peel-derived biochar composite was fabricated and applied as a low-cost adsorbent for the simultaneous extraction of morphine-like opioids named morphine, codeine, and 6-monoacetylmorphine from wastewaters, prior to their determination via liquid chromatography-mass spectrometry. A total of four biochar products were synthesized under different pyrolytic temperatures of 400, 500, 600, and 700°C, respectively, and the 400°C biochar was found to have the greatest extraction ability, with enrichment factors of 34, 58, and 61 for the three drugs. The primary adsorption mechanism includes π-π interaction and H-bonding. Parameters affecting the extraction of opioids were optimized. Under optimum conditions (such as pH = 7; adsorbent amount = 15 mg; sample volume = 20 ml; eluent solvent, 200 µl of methanol), the method was proved to be linear in the range of 0.05-10.0 µg/L, with coefficients of determination greater than 0.99, and the limits of detection were 0.006-0.010 µg/L. In-batch and inter-batch precisions were 1.8%-6.5% and 4.8%-10.6%, respectively. The method was successfully applied to the determination of the target opioids in the samples of influent and effluent wastewater. The developed method by using magnetic pomelo peel-derived biochar could potentially be applied for the effective estimation of illicit drug consumption.

Areca nut is a popular and addictive food as well as a traditional herbal medicine in many countries. Areca nut contains alkaloids including arecoline, guvacine, and arecaidine, which are the major bioactive compounds in areca products. Areca alkaloids can be carcinogenic, and thus sensitive and specific analytical methods are urgently desired for the identification and quantification of these compounds. High-performance liquid chromatography-based methods are often preferred, but areca alkaloids do not have chromophores, and detection using a traditional UV detector can be difficult. The complexity of areca sample extracts can also lead to the co-elution of peaks leading to poor quantitative performance. We report here high-performance liquid chromatography coupled with an ion mobility spectrometer for sensitive determination of areca alkaloids in various products including areca nut, areca nut products, and herbal oral liquid. An X-Bridge reversed-phase C

Ginseng is the main Chinese herbal medicine for tonifying Qi and invigorating the spleen. It has been used to treat spleen-qi deficiency with good protective effects for thousands of years, however, its biological mechanism has not been fully elucidated. This study aims to explore the mechanism of ginseng in the treatment of spleen-qi deficiency by using a comprehensive method combining metabolomics and network pharmacological analysis. Gas chromatography-mass spectroscopy was applied for investigating the changes in urine metabolites in spleen-qi deficiency rats and after treatment with ginseng. Metabolomics and network pharmacology analysis were applied to screen potential biomarkers and therapeutic targets of ginseng in the treatment of spleen-qi deficiency, respectively. Molecular docking was employed to further evaluate the docking mode of potential biomarkers and therapeutic target proteins. The results of metabolomics showed that the therapeutic effects of ginseng are mainly related to its regulation of three metabolic pathways. The molecular structure of potential biomarkers and common proteins was further analyzed by molecular docking to verify its effectiveness. Ginseng has good pharmacological effects by controlling key targets of related metabolic pathways, signal pathways, and potential biomarkers.

In this study, an acid-treated-activated carbon was prepared from chestnut oak shell carbonization followed by modification with hydrochloric acid/nitric acid and then used as a new sorbent for headspace needle-trap extraction of chlorophenol compounds from aqueous solutions. Different techniques, including scanning electron microscopy, nitrogen adsorption-desorption analysis, and Fourier transform-infrared spectroscopy were used for the characterization of the sorbents. The effects of some experimental parameters, including the temperature, pH, sorbent amount, and time of extraction were optimized. The developed method is fast and sensitive, providing low and sub ng/L detection limits. The limits of detection and quantification were in the range of 0.75-5 and 5-15 ng/ml, respectively, and the equilibrium time was 20 min. Wide linearity in the range of 15-2000 ng/L with R

Gerberae Piloselloidis Herba, a traditional Chinese medicine, is often employed to treat such lung-related diseases as coughs, asthma, and pulmonary carbuncles in southwest China. Our previous study demonstrated that its active fraction, prepared from Gerberae Piloselloidis Herba, exerts an obvious beneficial effect on asthma. However, the pharmacokinetics of its major constituents remain unclear. Therefore, an ultra-performance mass spectrometry-electrospray ionization-tandem mass spectrometry method was successfully established to simultaneously perform the pharmacokinetics of the main 11 components of the active fraction between normal and ovalbumin-induced asthmatic mice. Compared to the normal group, in asthmatic mice the peak concentration of arbutin, marmesin, caffeoylquinic acids, and flavonoid glycosides clearly increased, while for luteolin it significantly declined; the area under the curve for arbutin and luteolin showed an increase, but the values of marmesin, caffeoylquinic acids, and flavonoid glycosides revealed a decline; the peak time for arbutin, caffeoylquinic acids and flavonoid glycosides decreased, while for marmesin and luteolin it significantly augmented; apart from marmesin, the half-life for all compounds shortened significantly. It is indicated that the pathology of asthma could lead to an alteration in the pharmacokinetic profiles of the 11 components in plasma, providing a reference for further exploration of the pharmacodynamic basis of the anti-bronchial effect of Gerberae Piloselloidis Herba.

This review article provides a wide overview of important developments and applications of capillary electromigration methods in the area of peptide mapping of proteins in the period 1997-mid-2022, including review articles on this topic. It deals with all major aspects of peptide mapping by capillary electromigration methods: i) precleavage sample preparation involving purification, preconcentration, denaturation, reduction and alkylation of protein(s) to be analyzed, ii) generation of peptide fragments by off-line or on-line enzymatic and/or chemical cleavage of protein(s), iii) postcleavage preparation of the generated peptide mixture for capillary electromigration separation, iv) separation of the complex peptide mixtures by one-, two- and multidimensional capillary electromigration methods coupled with mass spectrometry detection, and v) a large application of peptide mapping for variable purposes, such as qualitative analysis of monoclonal antibodies and other protein biopharmaceuticals, monitoring of posttranslational modifications, determination of primary structure and investigation of function of proteins in biochemical and clinical research, characterization of proteins of variable origin as well as for protein and peptide identification in proteomic and peptidomic studies.

In the present study, an efficient strategy for the large-scale preparation of two minor polar polyphenols from Phyllanthus emblica L. has been established by macroporous resin column chromatography and high-temperature preparative high-speed counter-current chromatography. Macroporous resin column chromatography was used for the enrichment of the target polyphenols. The target polyphenols could be well enriched in the 10% ethanol fraction and the peak area proportion increased from 2.2% in the crude extract to 85.3% in the 10% ethanol fraction. Then, the 10% ethanol fraction was introduced to preparative high-speed counter-current chromatography for separation using an n-butanol-ethyl acetate-water (17:3:20, v/v/v) solvent system. In order to improve the retention of the stationary phase, a high-temperature preparative high-speed counter-current chromatography had been developed by using a 316 L stainless steel pipe as a column. A 50°C of column temperature was used and the retention rate of the stationary phase could reach 75%. Finally, 871 mg of compound Ⅰ and 534 mg of compound Ⅱ with purities higher than 98% were obtained from 4 g of the sample. The chemical structures were identified as corilagin and 1, 6-di-O-galloyl-β-D-glucoside by

Citrus, a raw material widely used in food and medicine, is susceptible to fungal infection and its metabolites during growth, transportation, and storage. Thus, monitoring the residual levels of various mycotoxins in Citrus traditional Chinese medicines and related products is crucial. This study described a simple, reliable, and sensitive method for simultaneous identification and quantification of 30 mycotoxins in Citrus products. The method is based on modified quick, easy, cheap, effective, rugged, and safe extraction and purification followed by ultra-high-performance liquid chromatography-quadrupole/orbitrap high-resolution mass spectrometry. The limit of detection ranged from 0.10 to 1.50 μg/kg, and the quantification ranged from 0.25 to 5.00 μg/kg. The recoveries at three spiked levels were 64.90-99.72% and the relative standard deviation was less than 12%. The method was applied to 55 Citrus samples. The detection rates of tentoxin and mycophenolic acid were the highest, reaching 22.7% and with concentration ranges of 0.33-1.03 and 0.57-2.09 μg/kg, respectively. All contamination levels were below the maximum residue limits recommended by the European Commission and China. These results could be used to establish guidelines for screening mycotoxins in Citrus products and the limits of acceptable levels.

Moscatilin, a bioactive ingredient isolated from Dendrobium moscatum, has been demonstrated to have excellent anti-cancer activity. The goals of the present study were to investigate the metabolic profiles of moscatilin and to identify and characterize its metabolites. In vitro studies were performed by incubating moscatilin (10 μM) with rat, dog, monkey, and human liver microsomes (0.5 mg protein/ml) to generate the metabolites. An analytical method of liquid chromatography combined with hybrid quadrupole orbitrap high-resolution mass spectrometry in full mass/data-dependent tandem mass spectrometry scan was utilized to separate and identify the metabolites in accordance with their accurate masses, formulas, and tandem mass spectrometry fragment ions determination. A total of six phase I metabolites were detected and structurally characterized. The phase I metabolic pathways of moscatilin were hydroxylation, demethylation, and dehydrogenation. In glutathione-supplemented liver microsomes, nine glutathione conjugates were detected and identified. Our results demonstrated that moscatilin was susceptible to bioactivation with the result of ortho quinone and quinone-methide intermediates. The present study provided an overview of the in vitro metabolic profiles of moscatilin, which will aid in the understanding of the efficacy and safety of this active compound.

Solid phase extraction combined with ultra-performance liquid chromatography-tandem mass spectrometry was developed for the simultaneous determination of 31 endocrine-disrupting chemicals in fish plasma. The strong anion exchange/primary-secondary amine cartridge and the mixed cation exchange cartridge were used in tandem instead of using a single mixed cation exchange cartridge for sample purification. Suitable eluents were selected for each of the two cartridges: 4.5% ammonia/acetonitrile solution for cartridges in tandem and acetone:n-hexane (V:V = 3:7) for the strong anion exchange/primary-secondary amine cartridge alone. With this optimized Solid phase extraction method, the recoveries of 31 endocrine disrupting chemicals were between 43.0% and 131.3%, the method detection limits were 0.45 to 1.35 ng/ml, and the limits of quantitation were 1.50-4.50 ng/ml. The innovative pretreatment method that connects two cartridges in tandem is well positioned to mitigate the matrix effects of fish plasma, thereby improving the accuracy of multiclass endocrine-disrupting chemicals determination. The significance of this method is to facilitate the application of the fish plasma model for the environmental risk assessment of endocrine-disrupting chemicals.

Successful isolation of 15 compounds from Polygonti rhizome was obtained by an efficient technique combined with macroporous resin column chromatography pretreatment and three different modes of high-speed counter-current chromatography for the first time. For the pretreatment, AB-8 resin was applied to remove the polysaccharides and enrich four different parts (samples I, II, III, and IV) by polarities. For the separation, sample I was separated by pH-zone-refining counter-current chromatography and seven cycle recycling mode high-speed counter-current chromatography, yielding four alkaloids (1--4); samples II-IV were further separated by the conventional high-speed counter-current chromatography, yielding seven flavonoids (5-10, 12), one steroid saponin (11), and three terpenoids (13-15). Finally, the isolates were assayed for their anti-inflammatory activities against nitric oxide production with compounds 5, 9-10, 13 showing significant anti-inflammatory activities, IC

Abemaciclib is an effective selective cyclin-dependent kinases 4 and 6 inhibitors for cancer therapy. The abemaciclib-related substances influence its efficacy and safety, and are important in process preparation studies and quality control. Thus, a reversed-phase high-performance liquid chromatography method was developed and validated for the detection of related substances in its bulk drug. The separation of abemaciclib and related substances was performed on a Phenomenon Gemini C18 column (4.6 × 250 mm, 5 μm) with a flow rate of 1.0 ml/min. The ultraviolet detection wavelength was 280 nm. Mobile phase A was composed of a mixed solution of aqueous solution and acetonitrile (9:1, v/v). The aqueous solution (pH 2.5) contained 0.025-mM potassium dihydrogen phosphate solution and 0.4% triethylamine. Mobile phase B was composed of acetonitrile. This novel method exhibits good system suitability, specificity, precision, stability, linearity (0.1-20 μg/ml), repeatability, and durability. Among abemaciclib and related substances, the lowest limit of detection and quantitation were 0.02 and 0.06 μg/ml, respectively, for abemaciclib. The recovery rates for related substances were above 95%. In addition, a novel degradation product was found during the process. In summary, a reliable reversed-phase high-performance liquid chromatography method was developed for abemaciclib-related substance detection in bulk drugs.

Metformin is one of the most commonly used drugs in the world for the treatment of type 2 diabetes, while ferulic acid is a molecule that stands out for its antioxidant potential. Recent studies demonstrate hypoglycemic synergy between these molecules. The objective of this study is to develop and validate an analytical methodology by high-performance liquid chromatography for the simultaneous quantification of these drugs in pharmaceutical formulations. The method used an octadecylsilane column and a mobile phase composed of 6 mM sodium lauryl sulfate in 15 mM phosphate buffer:ACN (65:35). Ferulic acid and metformin were monitored at 232 nm, with a mobile phase flow rate of 1 ml/min and oven temperature at 40°C. The method was linear in the range of 5-25 μg/ml for both molecules. In the presence of degradation products, satisfactory selectivity was achieved. Accuracy values were close to 100% and standard deviations in precision were less than 2%. In the robustness evaluation, the proposed variations did not interfere with the quantification. Therefore, it is concluded that the present method can be safely applied to the quality control of ferulic acid and metformin raw materials, as well as when they are combined in pharmaceutical formulations.

In this work, a simple, accurate, and rapid capillary electrophoresis with an indirect ultraviolet detection method was developed to simultaneous separate 10 biogenic amines. It was found that β-cyclodextrin and ethylene diamine tetraacetic acid facilitated the separation of tryptamine and tyramine, spermidine and spermine, respectively. The optimized background electrolytes consisted of 20.0 mmol/L imidazole, 8.0 mmol/L β-cyclodextrin, 0.5 mmol/L ethylene diamine tetraacetic acid, and 6.0% methanol (at pH 4.50 adjusted with acetic acid). The total analysis time of this method was less than 11 min with limits of detection in the range of 0.14-1.98 mg/L. The interday relative standard deviation of migration time and peak area were less than 1.36% and 4.44% (n = 6), respectively. To verify the applicability, this method was carried out to analyze biogenic amines in commercial luncheon meat samples. Due to the complex composition of luncheon meat, the real samples were rinsed with deionized water to reduce the influence of matrices. It was found that both storage temperature and protein content of the luncheon meat samples affected the biogenic amines content during storage. The results of this study are instructive for the storage of high-protein meat products.

A strong anion exchanger applied for ion chromatography is described by grafting methacrylamido propyl trimethyl ammonium chloride onto hydrolyzed poly(glycidyl methacrylate-divinylbenzene) substrate. The anion exchanger has been in detail characterized and the final capacity of the anion exchanger can be readily manipulated by different monomer amounts. It exhibited obvious temperature-sensitive properties and large tolerance to the samples with high ionic strength. The obtained anion exchanger demonstrated effective separation ability towards the common seven inorganic anions within 12 min and high separation efficiency, for example, 58 000/m of theoretical plate count for chloride.

A simple pretreatment method based on the combination of microwave-assisted extraction and dispersive micro solid phase extraction has been developed for the extraction of eprinomectin, doramectin, ivermectin, and abamectin from cow meat, liver, and kidney samples. The extracted drugs were determined using high-performance liquid chromatography equipped with a diode array detector. In this method, the solid samples were mixed with deionized water and organic solvent mixture, and the resulting mixtures were exposed to microwave irradiations to accelerate the analytes' extraction from the samples into the solution. Then, the supernatant was taken and mixed with a mixture of three sorbents optimized by a simplex centroid design. After vortexing and centrifuging, the sorbent particles were isolated and the adsorbed analytes onto the sorbent surface eluted with a natural deep eutectic solvent for more concentration. After centrifuging, the supernatant was taken and injected into the separation system. Acceptable repeatability (relative standard deviations ≤7.0%), high extraction recoveries (72%-86%) and enrichment factors (216-258), and low limits of detection and quantification (0.06-0.10 and 0.19-0.32 ng/g, respectively) were acquired. The method was successfully applied for the assessment of the analytes in the mentioned samples and ivermectin was found in three samples.

As the most abundant and bioactive constituent in vine tea (Ampelopsis grossedentata), dihydromyricetin possesses numerous biological activities. A rapid profiling and identification method for dihydromyricetin metabolites in rats after the oral administration has been established using ultra-high-performance liquid chromatography-Q-Exactive Orbitrap mass spectrometry coupled with multiple data-mining methods. Herein, an efficient analytical strategy characterized by a parallel reaction monitoring mode combining diagnostic fragment ions filtering techniques was developed for the comprehensive identification of dihydromyricetin metabolites in rat plasma, urine, and feces. And then, the biotransformation pathways of dihydromyricetin were further revealed. As a result, a total of 49 metabolites were finally identified by comparing diagnostic fragment ions, chromatographic retention times, neutral loss fragment ions, and accurate mass measurement with those of the dihydromyricetin reference standard. These metabolites were presumed to be dominantly generated through hydroxylation, dehydroxylation, methylation, reduction, sulfation, decarbonylation, glucuronidation, glucosylation, and their composite reactions. In a word, our present results not only supplied a solid foundation to better understand the action mechanism of dihydromyricetin, but also provided some models for the metabolism study of the other compounds in traditional Chinese medicines or natural plants.

The current research explains the stress degradation behavior of Apixaban, which is an anticoagulant or blood thinner. The degradation was conducted using hydrolytic, oxidative, thermal, and photolytic conditions. Apixaban is relatively stable in oxidative, thermal, and photolytic conditions; however, considerable degradation was observed in acid and base hydrolysis. Degradation products were identified using ultra-high performance liquid chromatography-mass spectrometry, isolated using semi-preparative high-performance liquid chromatography, and structural characterization by high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy. A total of five degradation products were identified and isolated in acid and base degradation. Degradation products 1, 2, and 3 were observed in acid conditions, whereas in base conditions, along with those three, two more degradation products 4 and 5 were identified. The representative thing was that among the five degradation products, two sets of positional isomers 1, 4, and 2, 5 were observed; out of which 2 and 5 are novel. The remaining degradation products 1, 3, and 4 are already reported tentatively using a single analytical technique of mass analysis without any evidence from nuclear magnetic resonance spectroscopy. Hence, the present study focused on using high-resolution mass, and nuclear magnetic resonance spectroscopy data for concrete confirmation of structures for degradation products.

North Patrininae herba, a perennial herbaceous plant, has long been used in traditional Chinese medicine to treat appendicitis, enteritis, and dysentery. Sonchus arvensis L., Sonchus oleraceus L., and Ixeris chinensis (Thunb.) Nakai are used as substitutes for North Patrininae in different regions, but the consistency of chemical composition and efficacy of these three species is still unknown. In this study, a detailed chemical analysis was carried out of the extract obtained from Sonchus arvensis L., Ixeris chinensis (Thunb.) Nakai and Sonchus oleraceus L. and a chemical component not previously reported in Ixeris chinensis (Thunb.) Nakai was found-Luteolin-7-O-(6''-malonylglucoside). The mechanism of action of the extract against inflammation and type II diabetes was investigated using network pharmacology and analysis of blood-absorbed components following oral dosing of rats. Finally, a highly accurate and reliable method was established for quality control purposes. The results showed that Sonchus arvensis L. and Sonchus oleraceus L. may be considered potential resources of a medicinal compound, whereas Ixeris chinensis (Thunb.) Nakai requires further evaluation.

Coreopsis tinctoria Nutt. (family Asteraceae) is a popular medicine-food plant, which improves chronic diseases such as hyperlipemia, hypertension, and diabetes. Flavanomarein is the main active component of Coreopsis tinctoria Nutt, in which the blood concentration of volunteers is low and bioavailability is poor. Thus, the understanding of flavanomarein metabolites and metabolic pathways is significant to clarify its effectiveness. This study systematically studied the metabolites of flavanomarein by oral and injection. The biological samples (feces, urine, and plasma) were analyzed by ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry in negative ion mode. The metabolic law of flavanomarein in the liver was further verified by a liver microsomal incubation experiment in vitro. A total of 12 metabolites were identified by oral administration while 15 metabolites were detected by injection. It was shown that metabolic pathways include acetylation, hydroxylation, glucuronidation, methylation, dehydrogenation, and so forth. The liver extraction rate of flavanomarein was 0.08, which means the metabolic stability of flavanomarein is well in rats' liver microsomes. It is a systematic study on the metabolism of flavanomarein and provides a metabolic rationale for further in-depth in vivo biotransformation.

Zhizi Baipi decoction is a classic traditional Chinese medicine formula for the treatment of jaundice and various liver diseases. The chemical components of Zhizi baipi decoction were not clear resulting of the paucity of relevant studies, which hindered the elucidation of the pharmacological mechanism, and the comprehensive development and utilization of Zhizi baipi decoction in clinical. In this study, ultra-performance liquid chromatography-quadrupole-time of flight mass spectrometry combined with the UNIFI natural product information analysis platform was used to rapidly analyze and identify the chemical components in Zhizi baipi decoction. A total of 122 chemical components, including 53 flavonoids, 16 alkaloids, 25 terpenoids, five phenylpropanoids, 14 organic acids, and seven others, were identified from Zhizi baipi decoction. These compounds may be the active components of Zhizi baipi decoction. The method established in this study can systematically, rapidly, and accurately resolve the chemical components in Zhizi baipi decoction, which lays the foundation for further establishment of the pharmacodynamic substance basis and quality control of Zhizi baipi decoction.

Assignment of inorganic mercury and methyl mercury mass fractions at an ultratrace level in soil certified reference material EnvCRM 03 with a complex matrix composition was undertaken. Inorganic mercury and methyl mercury contents by species-specific isotope dilution inductively coupled plasma mass spectrometry with on-line high-performance liquid chromatography or with classical off-line chromatography were established. Different extraction protocols: sequential extraction ((1) H

Favipiravir and Meropenem have been concurrently used as directly acting antiviral and antibiotic agents for the treatment of coronavirus disease in human plasma. Accurate and specific reversed phase ultra-performance liquid chromatographic and high-performance thin-layer chromatographic methods were developed and validated for the first time analysis of this combination in spiked human plasma using Cefepime as an internal standard. In the developed ultra-high-performance liquid chromatography method, separation was performed on a BEH C18 column with a mixture of ACN and 0.05 M potassium dihydrogen orthophosphate (pH = 3) in a ratio of 10:90 (v/v) as an eluate. Scanning of the separated peaks was at 298 nm. The developed method showed high sensitivity, and the drugs showed linearity in the range of 5-70 μg/ml for Favipiravir and 2-50 μg/ml for Meropenem. The proposed high-performance thin-layer chromatographic method included the separation using a mixture of ethyl acetate:methanol:deionized water:formic acid (5:4:1.5:0.3, by volume), then spots detection at 300 nm. Methods were investigated for greenness using the eco-scale and national environmental method index tools and were validated according to food and drug administration guidelines. Methods can be applied for bio-analysis and therapeutic drug monitoring studies.

Pavel Jandera was a world-leading analytical chemist who devoted his entire professional life to research in the field of high-performance liquid chromatography. During his scientific career, he worked at the Department of Analytical Chemistry at the University of Pardubice, Czech Republic. His greatest contribution to the field of liquid chromatography was the introduction of a comprehensive theory of liquid chromatography with programmed elution conditions. He was also involved in the research of gradient elution techniques in preparative chromatography, modeling of retention and selectivity in various phase systems, preparation of organic monolithic microcolumns, and, last but not least, in the development of theory and practical applications of two-dimensional liquid chromatography, mainly in the comprehensive form. In this review article, we have tried to capture the highlights of his scientific career and provide the readers with a detailed overview of Pavel Jandera's contribution to the evolution of separation sciences.

Titanium-based metal-organic framework MIL-125(Ti) was synthesized by the hydrothermal method of terephthalic acid and tetra butyl titanate in N-N,dimethylformamide, and methanol. MIL-125(Ti) was characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, nitrogen adsorption-desorption, energy-dispersive X-ray spectroscopy, zeta potential, scanning electron microscope, and transmission electron microscopy. The results showed MIL-125(Ti) could be used as a potential adsorbent for protein separation and purification due to the high specific surface area, high stability, and strong hydrophobicity. As a result, MIL-125(Ti) had adsorption selectivity for immunoglobulin G, which was due to the hydrogen bond between MIL-125(Ti) and protein. At pH 8.0, the maximum adsorption efficiency of 0.25 mg MIL-125(Ti) for 300 μL 100 μg/mL immunoglobulin G was 98.3%, and its maximum adsorption capacity was 232.56 mg/g. The elution efficiency of immunoglobulin G was 92.4% by 0.1% sodium dodecyl sulfate. sodium dodecyl sulfate-polyacrylamide gel electrophoresis result demonstrated the successful isolation of highly purified immunoglobulin G from the human serum. Therefore, a new method of separation and purification of immunoglobulin G in human serum using titanium-based metal-organic framework MIL-125(Ti) as a solid-phase adsorbent was established, which broadened the application scope of metal-organic frameworks.