Optimized analysis for related substances in spiramycin based on high performance liquid chromatography with hybrid particle column and characterization of its impurities by single heartcut two-dimensional liquid chromatography coupled with quadrupole time-of-flight mass spectrometer.

This article described the development and validation of a method for spiramycin related substances based on hybrid particle column. The chromatographic conditions were as follows: water - 0.2 mol/L dipotassium hydrogen phosphate (the pH value adjusted to 9.5 using a 1 mol/L KOH solution) - acetonitrile - methanol (10: 60: 28.5: 1.5, v/v/v/v) as mobile phase A, water - 0.2 mol/L dipotassium hydrogen phosphate (pH 9.5) - acetonitrile - methanol (10: 30: 57: 3, v/v/v/v) as mobile phase B and gradient elution was performed. Compared with previous analytical methods, this method has strong specificity, excellent sensitivity and stability, which could be used for the daily testing of related substances of spiramycin. Furthermore, impurities above 0.1 % were characterized using two-dimensional liquid chromatography coupled with quadrupole time-of-flight mass spectrometer (2D LC-QTOF-MS/MS) and there were 6 impurities reported for the first time.

Rapid Identification of Chemical Constituents of Sanhua Decoction in Vivo and in Vitro and the Metabolites of Rhubarb Anthraquinone Aglycone by Ultra-High Performance Liquid Chromatography Coupled with Quadrupole Time-of-Flight Tandem Mass Spectrometry.

Sanhua Decoction (SHD) is a classic prescription for the treatment of stroke in the clinic. Based on the combination strategy in vitro and in vivo, the chemical constituents of SHD were characterized by ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry, and the metabolites of five effective anthraquinone aglycones (emodin, chrysophanol, rhein, aloe-emodin, and physcion) of rhubarb in SHD were studied. A total of 222 compounds were isolated and identified in vitro, including 50 flavonoids and their glycosides, 41 coumarins, 22 anthraquinones, 22 tannins, 14 phenylpropanoids, 16 alkaloids, 18 organic acids and their esters, 14 lignans, six anthrones, and 19 other compounds. A total of 111 prototype components were isolated and identified in vivo. Among them, 26, 82, 101, and 46 prototype components and 87 metabolites were detected in plasma, urine, feces, and bile for the first time. This study provides a basis for the identification of chemical components in vivo and in vitro and the analysis of potential pharmacodynamic components of SHD, and provides a basis for further study of pharmacodynamic mechanism.

Suspect screening candidate exposure biomarkers of acetyl tributyl citrate and acetyl triethyl citrate after human oral administration.

Acetyl tributyl citrate (ATBC) and acetyl triethyl citrate (ATEC) are widely used as plasticizers, but their metabolites as exposure biomarkers for biomonitoring, as well as approximate human metabolic pathways, are not well understood. This study addresses this knowledge gap by conducting suspect screening to propose specific metabolites in human urine as potential biomarkers of exposure and explore their kinetic profiles. Ten volunteers were administered deuterium labeled ATBC (ATBC-d3) and seven received ATEC or deuterium labeled ATEC (ATEC-d3), with urine samples collected over 48 h post-administration. Employing ultra-performance liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry (UPLC-qTOF/MS), six metabolites of ATBC were consistently detected, including (OH)3-ATBC-d3, ADBC-d3, OH-ADBC-d3, DBC, OH-DBC, and OH-DBA. For ATEC, four metabolites were identified: ADEC-d3, AMEC-d3, OH-ADEC-d3, and DEC. Based on their high detection frequency, relative response, and specificity to their parent compounds, ADBC-d3 and OH-ADBC-d3 were identified as promising candidate biomarkers for ATBC exposure, while ADEC-d3 emerged as a suitable biomarker for ATEC. Estimated urinary elimination half-lives ranged from 1.0 to 9.9 h for ATBC metabolites and 1.6 to 3.0 h for ATEC metabolites. One-compartment kinetic modeling provided preliminary insights into metabolite kinetics. This research advances the understanding of ATBC and ATEC metabolism in humans, providing a foundation for future exposure assessments and toxicological studies. The identified biomarkers and preliminary metabolic profiles offer valuable starting points for biomonitoring and risk assessment of these alternative plasticizers.

Lactation-promoting ingredients of Hemerocallis citrina Borani and the corresponding mechanisms.

Hemerocallis citrina Borani is a traditional folk food used to promote the lactation of postpartum mothers in China; however, the active ingredients and corresponding mechanisms are still unknown. In this study, the lactogenic effect of alcoholic and aqueous extracts of H. citrina was primarily evaluated, and the aqueous extract (1,000 and 2,000 mg/kg) displayed significant lactation-promoting effects. Three eluates of the aqueous extract (0%, 30%, and 50%HCW) were further evaluated for their lactogenic effect, and 30% and 50% HCW showed significant lactation-promoting activity. Nineteen ingredients, including those with a high content of rutin and isoquercetin, were then identified from 30% and 50%HCW using the ultra-performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry (UPLC-Q-TOF-MS) method. Finally, the lactogenic effect of rutin and isoquercetin was evaluated, and both compounds displayed significant lactation-promoting activity. The mechanisms relative to the lactation-promoting active ingredients for H. citrina extracts and compounds are to stimulate the release of prolactin (PRL) and progesterone (P), as well as to induce the expression of prolactin receptor (PRLR) and improve the morphology of mammary tissue. This study first clarified the lactation-promoting active ingredients of H. citrina and the corresponding mechanisms, which provide a new insight into the new lactation-promoting drug and promote the high-value utilization of H. citrina resources.

Simultaneous metabolomics and lipidomics analysis based on 4in1 online analysis system reveal metabolic signatures in atherosclerotic mice.

Developing efficient and comprehensive analysis methods for metabolomics and lipidomics in the biological tissues and body fluids is essential for understanding the disease mechanisms. Although various two-dimensional liquid chromatography-mass spectrometry (2D-LC-MS) methods have been proposed to expand metabolite coverage, achieving higher efficiency in integrated metabolomics and lipidomics studies remains a technical challenge. In this work, a novel 4in1 online analysis system with excellent reproducibility and mass accuracy was constructed for metabolomics and lipidomics study in various biological samples from atherosclerotic mice. This system enabled the simultaneous detection in both positive and negative ion modes with extensive polarity separation in a single analytical run. Using the 4in1 online analysis system, we identified distinct but complementary metabolic signatures associated with atherosclerosis in different biological samples. Specifically, a total of 230 and 170 differential metabolites or lipids were detected in mice plasma samples and aortic tissue samples, respectively, including glycerophospholipids, sphingolipids, fatty acyls, glycerolipids, carboxylic acids, and pyrimidine nucleosides. Additionally, atherosclerosis-related metabolic pathways involved in biosynthesis of unsaturated fatty acids, sphingolipid metabolism, cholesterol metabolism, glycerophospholipid metabolism, and choline metabolism further revealed. These findings demonstrate that the novel 4in1 online analysis system is a faithful, stable and powerful tool for comprehensive metabolomics and lipidomics studies in complex biological matrices.

[Chemical components and in vitro anti-aging activity of Yangxue Qingnao Wan based on UPLC-Q-TOF-MS/MS].

The main chemical components of Yangxue Qingnao Wan(YXQNW) were analyzed and identified by ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry(UPLC-Q-TOF-MS/MS). According to the mass spectrometry information, Mass Hunter 10.0 analysis software was used to compare the collected quasi-molecular ion peaks and secondary fragment ions with literature and reference substances. A total of 131 compounds were identified from YXQNW, including 11 phenylpropanoids, 11 flavonoids, 42 nitrogen-containing compounds, 12 terpenoids, 17 phthalides, 23 quinones, and 15 other compounds. The anti-aging activity of YXQNW and six compounds from YXQNW, including rosmarinic acid, gallic acid, rutin, umbelliferone, hyperoside, and vanillic acid, were evaluated by D-galactose(D-gal)-induced HT22 cell senescence model. The effects of the compounds on HT22 cell damage and individual cell proliferation ability were observed from overall and individual perspectives by the Beyo Click~(TM) EdU-555 cell proliferation kit, and apoptosis was detected by the Annexin V-FITC/PI double staining apoptosis detection kit. Finally, the anti-aging effect of the compounds was tested by a cell senescence ß-galactosidase staining kit. This study provides a more comprehensive analysis of the chemical components of YXQNW and evaluates its anti-aging effect, which will provide a scientific basis for basic research on the efficacy of YXQNW for the treatment of various neurological diseases, such as Alzheimer's disease(AD), headache, and memory loss.

Validation of Active Compound of Terminalia catappa L. Extract and Its Anti-Inflammatory and Antioxidant Properties by Regulating Mitochondrial Dysfunction and Cellular Signaling Pathways.

As chronic inflammation and oxidative stress cause various diseases in the human body, this study aimed to develop functional materials to prevent inflammation and oxidative stress. This study investigated the biological function and components of Terminalia catappa L. extract prepared using its leaves and branches (TCE). TCE was determined using ultraperformance liquid chromatography-quadrupole-time-of-flight mass spectrometry. Using RAW 264.7 mouse macrophages, inhibitory effects of the identified compounds on nitric oxide (NO) and reactive oxygen species (ROS) generation were analyzed. Therefore, α-punicalagin was selected as an active compound with the highest content (986.6 ± 68.4 µg/g) and physiological activity. TCE exhibited an inhibitory effect on lipopolysaccharide (LPS)-induced inflammatory markers, including NO, inducible nitric oxide synthase, and inflammatory cytokines without exerting cytotoxicity. Moreover, TCE prevented excessive ROS production mediated by LPS and upregulated hemeoxygenase-1 expression via the nuclear translocation of nuclear factor erythroid 2-related factor 2. Interestingly, TCE prevented LPS-induced mitochondrial membrane potential loss, mitochondrial ROS production, and dynamin-related protein 1 phosphorylation (serine 616), a marker of abnormal mitochondrial fission. Furthermore, TCE considerably repressed the activation of LPS-induced mitogen-activated protein kinase pathway. Thus, TCE is a promising anti-inflammatory and antioxidant pharmaceutical or nutraceutical, as demonstrated via mitochondrial dysfunction and cellular signaling pathway regulation.

Identification of candidate exposure biomarkers for acetyl tributyl citrate and acetyl triethyl citrate using suspect screening in human liver microsomes.

Acetyl tributyl citrate (ATBC) and acetyl triethyl citrate (ATEC) are increasingly used as alternatives to phthalates in various products, including food packaging, medical devices, and personal care items, raising concerns about their potential health impacts. This study aimed to investigate the in vitro human metabolism of ATBC and ATEC and identify potential exposure biomarkers applicable in human biomonitoring. Pooled human liver microsomes were utilized to conduct in vitro metabolism assays of deuterium labeled ATBC (ATBC-d3) and ATEC, and ultra performance liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry (UPLC-qToF/MS) was employed for analysis. Suspect screening workflow and confidence level assignment were applied for metabolite identification. Time-course analysis revealed rapid metabolism of both compounds, with estimated apparent half-lives of approximately 5 min for ATBC-d3 and less than 15 min for ATEC. Eleven metabolites were identified for ATBC-d3 and six for ATEC. The predominant chemical reactions observed were carboxylic ester hydrolysis, deacetylation, and hydroxylation. Based on their abundance and specificity, MB1 (hydroxylated) and MB11 (hydrolyzed and hydroxylated) were proposed as candidate exposure biomarkers for ATBC, and ME1 (hydrolyzed and deacetylated) for ATEC. The identified metabolites and proposed sequences of kinetic process enhance our understanding of the fate of these compounds in the human body, potentially informing future toxicological assessments and guiding the development of more comprehensive human biomonitoring strategies.

[Identification of chemical components of large-leaf yellow tea by ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry].

Large-leaf yellow tea, a slightly fermented yellow tea that is unique to China, has a stronger hypoglycemic effect than other tea varieties, such as green and black tea. Research on large-leaf yellow tea has focused on its hypoglycemic effect owing to the lack of comprehensive techniques to characterize its chemical components; thus, its development and further promotion are limited. Therefore, the development of a reliable analytical method to fully characterize the chemical components of large-leaf yellow tea is urgently required. In this study, a reliable strategy based on the data-acquisition technology of ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q TOF/MS) was established to rapidly screen and analyze the main chemical components of large-leaf yellow tea by combining the information of neutral loss groups and characteristic fragment ions. The chromatographic separation experiments were performed on a Waters ACQUITY UPLC BEH C18 column (100 mm×2.1 mm, 1.7 µm) with gradient elution using 0.1% formic acid aqueous solution and acetonitrile as the mobile phases. The flow rate was 0.2 mL/min, the sample volume was 2 µL, and the column temperature was 35 ℃. The mass spectral information of the components in a large-leaf yellow tea solution was collected using the full-information tandem MS (MSE) technique in positive and negative ion modes. The specific chemical components of large-leaf yellow tea was identified as follows. First, a self-established database of tea chemical components was constructed based on the literature. The mass spectral cleavage pathways of different types of compounds in large-leaf yellow tea were then sorted using reference substances, and the characteristics of the fragment ions and neutral loss groups were summarized. The precise mass-to-charge ratio of the target chemical components were then obtained based on the mass spectral information. Finally, the structures of the compounds in large-leaf yellow tea were confirmed based on their chromatographic retention times, mass spectral cleavage pathways, characteristic fragment ions, and neutral loss groups. A total of 87 chemical components, including 10 catechins, 32 flavonoids, 16 phenolic acids, 12 tannins, 6 theaflavins, and 11 compounds in other classes, were identified in large-leaf yellow tea. Representative compounds of various classes, including gallocatechin gallate, quercetin, vitexin, gallic acid, chlorogenic acid, 1,3,6-tri-O-galloyl-ß-D-glucose, and theaflavin, were selected, and their characteristic fragment ions and neutral loss groups were investigated in detail to reveal the cleavage pathways of different types of compounds in large-leaf yellow tea. The UPLC-Q TOF/MS method established in this study can comprehensively identify the main chemical components of large-leaf yellow tea in a simple, highly sensitive, stable, and reliable manner. This study provides a scientific basis and data support for the discovery of functional ingredients and quality evaluation of large-leaf yellow tea.

Study on the chemical composition of Gegen-Tianma decoction and its absorbed constituents in rat plasma, brain based on UPLC-Q-TOF-MS and DESI-MSI.

In traditional Chinese medicinal practices, Gegen (GG) and Tianma (TM) are widely utilized for headache relief, but their material basis has not been comprehensively characterized. This research utilized ultra performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UPLC-Q-TOF-MS) for precise determination of Gegen-Tianma's (GGTM) material composition, and employed desorption electrospray ionization-mass spectrometry imaging (DESI-MSI) to pinpoint the brain-absorbed components and various metabolites post oral administration to rats. A total of 80 chemical constituents were identified from GGTM, 11 prototypes and 18 metabolites were identified from plasma. The brain tissue was identified in total 4 prototypes and 5 metabolites, these constituents were basically located in the prefrontal cortex and thalamus. The absorption patterns of components in the rat brain aligned with the varied distribution of metabolites within the brain. This study provides a solid theoretical basis for in-depth exploration of potential drug targets and elucidation of the specific mechanism of action of GGTM in the treatment of migraine.

Targeted metabolomics assisted rapid screening and characterization of aristolochic acids and their DNA adducts in aristolochia plants by ultra-high performance liquid chromatography coupled with ion mobility quadrupole time-of-flight mass spectrometry.

Aristolochic acids are one of the major compounds in aristolochia plants, which are nephrotoxic and carcinogenic. A method was established for the detection and identification of aristolochic acids and their DNA adducts in four different herbs using ultra-high performance liquid chromatography-ion mobility quadrupole time-of flight mass spectrometry. Solid phase extraction conditions were optimized to improve the sensitivity of the experiment by using 40 mg of C18 as adsorbent and 100 µL ethanol as elution solvent. At a collision energy of 10-40 eV, these compounds and cleavage patterns were precisely identified and analyzed by secondary fragmentation and collision cross section values. The obtained mass spectrometry data were then analyzed by targeted metabolomics, including principal component analysis, partial least squares-discriminant analysis and hierarchical clustering analysis, and importing the samples in the established model, the confidence values can reach 0.61 and 0.76. All in all, this method can provide a useful tool for the detection of aristolochic acids and deoxyribonucleic acid adducts. In conclusion, this method was successfully used for the detection and identification of aristolochic acids and their DNA adducts.

Elucidation of γ-glutamyl-ß-cyanoalanylglycine biosynthesis in mammalian cells by LC-QTOF-MS.

γ-Glutamyl-ß-cyanoalanylglycine (gEcnAG) is a glutathione analog in which the cysteine moiety in glutathione is replaced with ß-cyanoalanine, a known plant cyanide metabolite. Previously, gEcnAG was detected in the liver of rats and chicks exposed to ß-cyanoalanine. We reported the detection of gEcnAG in naïve mammalian cells using liquid chromatography coupled with tandem quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). LC-QTOF-MS analysis enabled high-resolution confirmation (exact mass determination and MS/MS fragmentation) of the gEcnAG structure. The detection of gEcnAG in rat pheochromocytoma (PC12) cells that were not exposed to ß-cyanoalanine suggests its endogenous production. Furthermore, the inhibition of myeloperoxidase, an enzyme potentially required for endogenous cyanide generation, decreased gEcnAG levels in PC12 cells. This supports the notion that PC12 cells intrinsically produce cyanide, unlike HepG2 cells, which exhibited lower intracellular gEcnAG levels. Notably, ß-cyanoalanine was undetectable in PC12 cells. Moreover, depleting glutathione with buthionine sulfoximine reduced intracellular gEcnAG levels, whereas supplementation with glutathione reduced ethyl ester increased them. These observations suggest that endogenous gEcnAG may be generated from glutathione, potentially through its reaction with endogenous cyanide. Our findings implicate gEcnAG as a possible metabolite of endogenous cyanide.

[Metabolite identification and metabolic pathway analysis of Platycodonis Radix extracts from Tongcheng city in rats].

In this study, we delved into the prototypical components and metabolites of Platycodonis Radix extracts(PRE) from Tongcheng city in plasma, urine and feces of rats, and revealed its metabolic pathways and metabolic rules in vivo. The prototypical components and metabolites of PRE in rats were characterized and identified by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS) and mass defect filter(MDF). The biological samples were analyzed by ACQUITY UPLC BEH C_(18)(2.1 mm×100 mm, 1.7 µm), with 0.1% formic acid water(A)-0.1% formic acid acetonitrile(B) as mobile phase, and the biological samples were analyzed in negative ion mode by electrospray ionization mass spectrometry(ESI-MS). Twelve prototypical saponins and twenty-seven metabolites were detected in plasma, urine and feces of rats treated with PRE by oral administration. Eleven prototypical components and nine metabolites were detected in plasma, eleven prototypical components and eight metabo-lites were detected in urine, and ten prototypical components and twenty metabolites were detected in feces. Further studies showed that the metabolic pathways of PRE in rats mainly include oxidation, reduction, acetylation, stepwise hydrolytic deglycosylation, glucuronidation and so on. This study provides a scientific basis for clarifying the pharmacological basis and mechanism of PRE from Tongcheng city.

A multi-component, multi-target, and multi-pathway prediction method for Chinese medicine based on the combination of mass spectrometry analysis and network analysis: An example using Weifuchun.

Weifuchun, a Chinese medicinal prescription made from herbs of natural origin including Hongshen (Ginseng Radix et Rhizoma Rubra), Xiangchacai (Rabdosia Amethystoides), and Zhiqiao (Aurantii Fructus), has attracted increasing attention for clinically treating chronic atrophic gastritis, which is characterized by the chronic inflammation of the gastric mucosa leading to progressive loss of gastric glandular cells. To investigate the active ingredients and potential mechanisms of WFC, it was analyzed using a novel multi-component, multi-target, and multi-pathway prediction method. High/ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC/UPLC-Q-TOF-MS) was employed to separate and profile the chemical constituents of WFC with high precision and efficiency. Network analysis and molecular docking were used to predict bioactive compounds and their interactions with biological targets. The results highlight 42 significant compounds potentially contributing to the therapeutic effects of WFC by effecting on several key pathways, including proved PI3K/Akt, NF-κB, and JAK/STAT signaling pathways. This study showcases the efficacy of combining advanced chromatographic techniques with computational methods to elucidate the pharmacological mechanisms of complex botanical drugs.

Effect on serum metabolomics of rats with premature ovarian insufficiency by Zhibian (BL54) through Shuidao (ST28) acupuncture.

OBJECTIVE: To analyze the serum metabolic targets of the "Zhibian (BL54) through Shuidao (ST28)" acupuncture technique in cyclophosphamide (CTX)-induced premature ovarian insufficiency (POI) model rats and to elucidate the potential molecular mechanism of acupuncture in improving POI. METHODS: We used an intraperitoneal injection of CTX to establish the POI rat model (POI group) and compared serum hormone levels and ovarian histopathological changes to evaluate the effect of the Zhibian (BL54) through Shuidao (ST28) technique (ZS + POI group) on ovarian function. Then, nontargeted metabolomics was performed using rat serum by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS). RESULTS: After acupuncture intervention, the serum hormone levels and ovarian pathological morphology of POI rats were effectively improved. Moreover, UPLC-Q-TOF/MS results showed that the ZS + POI group showed a significant reversal of the levels of 6 differential metabolites. Among them, the levels of four serum metabolic markers, divanillyltetrahydrofuran ferulate, trans-ferulic acid, tryptamine, and neuraminic acid, increased significantly. Further analysis of biological effects showed that all metabolites were involved in the regulation of reproductive hormone levels and antioxidant and antiapoptotic effects. CONCLUSIONS: The "Zhibian (BL54) through Shuidao (ST28)" acupuncture method may improve the ovarian function of POI rats by regulating serum metabolite markers to exert antioxidant and antiapoptotic effects, which provides a theoretical basis for the clinical application of acupuncture in the treatment of POI.

Desorption of Positive and Negative Ions from Areoles of Opuntia microdasys Cactus at Atmospheric Pressure: Cactus-MS.

The areoles and spines of cacti can be used to desorb ions of ionic liquids (ILs) by the mere action of an electric field into the atmospheric pressure (AP) interface of a mass spectrometer. The small cactus species Opuntia microdasys bears numerous very fine hairs on its areoles and tiny sharp spines that appeared suited to serve as needle electrodes sharp enough for field desorption of ions to occur. In fact, positive and negative ions of four ILs could be desorbed by a process analogous to AP field desorption (APFD). In contrast to APFD where activated field emitters are employed, the ILs were deposited onto one or two adjacent areoles by applying 1-3 µL of a dilute solution in methanol. After evaporation of the solvent, the cactus was positioned next to the spray shield electrode of a trapped ion mobility-quadrupole-time-of-flight instrument. Desorption of IL cations and IL anions, respectively, did occur as soon as the electrode was set to potentials in the order of ±4.5 kV, while the cactus at ground potential was manually positioned in front of the entrance electrode to bring the areole covered with a film of the sample into the right position. Neither did mixing of ILs occur between neighboring areoles nor did the cactus suffer any damage upon its use as a botanical field emitter.

[Impurity profile analysis of amphotericin B using on-line two-dimensional high performance liquid chromatography-quadrupole time-of-flight mass spectrometry].

Amphotericin B (AmB) is a polyene-macrolide antimicrobial drug with a broad antibacterial spectrum and remarkable efficacy against deep fungal infections. It binds to ergosterol on the fungal cell membrane and alters its permeability, thereby destroying the membrane. AmB is a multicomponent antimicrobial medication that contains a wide range of impurities, rendering quality analysis extremely difficult. In the current Chinese Pharmacopoeia (Edition 2020) and European Pharmacopoeia (EP10.3), high performance liquid chromatography (HPLC) is applied to examine related substances in AmB. However, this technique presents a number of issues. For instance, the mobile phases used in the HPLC method described in both references contain nonvolatile inorganic salts, which cannot be coupled with a mass spectrometry (MS) detector. In addition, because the mobile phases used have a low pH, the component/impurities of AmB drug can easily be degraded or interconverted during the analytical process, leading to reduced analytical accuracy. Therefore, the accuracy and sensitivity of this method must be improved. In this study, a method based on on-line two-dimensional high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (2D HPLC-Q TOF/MS) was developed to analyze the impurity profile of AmB in accordance with the Chinese Pharmacopoeia (Edition 2020) and European Pharmacopoeia (EP10.3). The method combines on-line dilution and a multiple-capture HPLC system to achieve the efficient separation of AmB component/impurities. It also resolves the issue of poor solvent compatibility in 2D HPLC, increases the analytical flux, enhances the automation capability, reduces the mutual conversion of AmB and its impurities during the analytical process, and increases the detection sensitivity of the method. MS was also used to determine the structural inference of unstable components and impurities. An XBridge Shield C18 column (250 mm×4.6 mm, 3 µm) was used for first-dimensional-liquid chromatography with gradient elution using methanol-acetonitrile-4.2 g/L citric acid monohydrate solution (10∶30∶60, v/v/v, pH 4.7) as mobile phase A and methanol-acetonitrile-4.2 g/L citric acid monohydrate solution (12∶68∶20, v/v/v, pH 3.9) as mobile phase B. An Xtimate C8 column (10 mm×2.1 mm, 5 µm) was used as the trap column, and trapping and desalting were performed using 10 mmol/L ammonium formate aqueous solution containing 0.1% formic acid-acetonitrile (95∶5, v/v). An Xtimate C8 column (250 mm×2.1 mm, 5 µm) was used for second-dimensional-liquid chromatography with gradient elution using 10 mmol/L ammonium formate aqueous solution containing 0.1% formic acid-acetonitrile (95∶5, v/v) and 10 mmol/L ammonium formate aqueous solution containing 0.1% formic acid-acetonitrile (5∶95, v/v) as mobile phases. The data were collected in positive-ion mode. In this study, the structures of six impurities in amphotericin B were inferred, according to the fragmentation, the MS and MS2 spectra of each impurity. The developed method can be used to quickly and sensitively analyze the impurity profile of AmB. Furthermore, the research results on impurity profiles can be applied to guide improvements in AmB production.

Effect of Stewing Time on the Small Molecular Metabolites, Free Fatty Acids, and Volatile Flavor Compounds in Chicken Broth.

Chicken broth has a taste of umami, and the stewing time has an important effect on the quality of chicken broth, but there are fewer studies on the control of the stewing time. Based on this, the study was conducted to analyze the effects of different stewing times on the sensory, small molecular metabolites, free fatty acids, and volatile flavor compounds contents in chicken broths by liquid chromatography-quadrupole/time-of-flight mass spectrometry, gas chromatography-mass spectrometry, headspace solid-phase microextraction, and gas chromatography-mass spectrometry. Eighty-nine small molecular metabolites, 15 free fatty acids, and 86 volatile flavor compounds were detected. Palmitic and stearic acids were the more abundant fatty acids, and aldehydes were the main volatile flavor compounds. The study found that chicken broth had the best sensory evaluation, the highest content of taste components, and the richest content of volatile flavor components when the stewing time was 2.5 h. This study investigated the effect of stewing time on the quality of chicken broth to provide scientific and theoretical guidance for developing and utilizing local chicken.

Analytical strategies to identify multicomponent quality markers for commercial Hua-ju-hong using multidimensional chemical analysis.

Hua-ju-hong (HJH) is a Chinese medicinal material obtained from Citrus grandis 'Tomentosa' (CGT) and Citrus grandis (L.) Osbeck (CG) with various commercial specifications. It is known for relieving cough and dispelling phlegm. To reveal the quality marker for distinguishing the various HJH, 215 batches of commercial HJH were studied systematically using multidimensional chemical analysis. Ten major components were identified by high-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry and quantified via high-performance liquid chromatography coupled with diode array detection. In this study, a rapid, efficient, and low-cost chromatographic method was established. Total coumarin-hemiterpene and total coumarin-monoterpene were first classified and analyzed in HJH. The result indicated that the main component, naringin, was not the quality marker for differentiating CGT from CG. For reflecting the unique medicinal and food value of HJH, coumarins should be the more potential quality markers. Flavonoids were the possible quality markers for distinguishing two growth stages of fruit-exocarp and young fruit. For the first time, two chemotypes of HJH were identified in CG. This study provides a convenient yet reliant chromatographic method and novel yet systematic strategies for overall quality control of commercial HJH.

Integrated identification-quantification (ID-Quant) workflow utilizing UPLC-QTOF-MS for the therapeutic drug monitoring of multi-component antibiotics without pure standards: Validation using teicoplanin.

The lack of individual pure standard has hampered the application of therapeutic drug monitoring (TDM) for multi-component antibiotics in clinical laboratories. Here, we aimed to develop an integrated identification-quantification (ID-Quant) workflow based on ultra-high-performance liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry (UHPLC-QTOF-MS) to enable the comprehensive determination of all teicoplanin components without needing pure standards. The workflow comprises three steps. First, non-targeted MSE full scanning was used to detect and identify all potential ingredients. Then, characteristic product ions were selected to generate a quantitative time-of-flight multiple reaction monitoring (Tof-MRM) method. Finally, the constituent composition of teicoplanin injection was determined and utilized as an alternative reference standard to monitor the teicoplanin ingredients in human serum samples. As a result, nine teicoplanin analogs were identified from teicoplanin injection (Sanofi-Aventis, France). The overall performance of the Tof-MRM method was satisfactory in terms of linearity, precision, accuracy, and limits of detection. Utilizing the drug as standard, the individual concentrations for each component in patient serum were determined to be 0.120 µg/mL (A3-1), 0.020 µg/mL (N-1), 0.550 µg/mL (N-2), 0.730 µg/mL (A2-1), 4.26 µg/mL (A2-2,3), 4.79 µg/mL (A2-4,5), and 0.290 µg/mL (N-3), respectively. The distribution pattern of teicoplanin components was also discovered to differ from that in the drug injection. Overall, this integrated ID-Quant workflow based on UHPLC-QTOF-MS enables the robust quantitation of all teicoplanin analogs without the need for individual pure standard. This approach could help address the standard unavailability problem in the TDM of multi-component antibiotics.