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Background Volatile organic compounds (VOCs) in exhaled breath are closely associated with respiratory diseases and are linked to various metabolic reactions in the human body. A quantitative analytical method can provide technical support for studying VOCs related to various diseases. Objective To establish a thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method for the determination of 27 VOCs in exhaled breath. Methods VOCs in exhaled breath were collected using a Bio-VOC sampler and enriched with Tenax TA thermal desorption tubes before TD-GC-MS analysis. Standards were collected using thermal desorption tubes and optimized for thermal desorption conditions as well as chromatographic and mass spectrometric conditions: The separation of the 27 VOCs was achieved by an optimized temperature program, the improvement of sensitivity by optimizing quantitative ions, and the increase of VOCs desorption efficiency by optimizing thermal desorption time and temperature. Limit of detection, limit of quantification, accuracy, precision, and stability of the proposed method were investigated by spiking with a blank gas bag, and exhaled breath samples from 20 healthy individuals were collected for an application study of the proposed method. Results The thermal desorption temperature was 280 ℃, and desorption time was 6 min. A VF-624ms chromatographic column was selected for the separation of target substances. The initial temperature of heating program was 35 ℃, maintained for 1 min, and then increased to 100 ℃ at a heating rate of 3 ℃·min−1 for 1 min, followed by increasing to 210 ℃ at a heating rate of 28 ℃·min−1 for 5 min. A quantitative analysis was conducted with a single ion monitoring (SIM) mode. Under these conditions, the 27 VOCs showed good linear relationships in their respective concentration ranges and the correlation coefficients were higher than 0.9990. The limits of detection of the method were in the range of 0.01-0.13 nmol·mol−1, the limits of quantification were in the range of 0.02-0.44 nmol·mol−1, and the spiked recoveries were in the range of 80.1%-120.5%, with intra-batch and inter-batch precision ≤ 18.8% and 17.9% respectively. All substances can be stored at room temperature (23-28 °C) for 7 d and at 4 °C for 14 d. The proposed method was applied to exhaled breath samples from 20 subjects with detection rates≥ 80% (except for trans-2-pentene and decane) and a concentration range of 0.00-465.50 nmol·mol−1. Conclusion The established TD-GC-MS method for quantification of VOCs in exhaled breath is characterized by high sensitivity and good accuracy, and is suitable for quantitative determination of VOCs in exhaled breath, which can provide technical support for the study of exhaled breath VOCs.
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ObjectiveTo investigate the mechanism of Atractylodis Macrocephalae Rhizoma（AMR） in the treatment of slow-transmission constipation（STC） by observing the effects of AMR on short-chain fatty acids and intestinal barries in STC mice. MethodForty-eight male KM mice were randomly divided into blank group， model group， AMR low-， medium-， high-dose groups（2.5， 5， 10 g·kg-1） and mosapride group（2.5 mg·kg-1）. Except for the blank group， all groups were gavaged with loperamide suspension（5 mg·kg-1） twice daily for 14 d to construct the STC mouse model. At the same time， each drug administration group was given the corresponding drug by gavage for consecutive 14 d， the blank and model groups were gavaged with equal volume of distilled water. The effects of the treatment of AMR on body mass， defecation frequency， fecal water content and intestinal propulsion rate of mice were observed， the pathological changes of mouse colon were observed by hematoxylin-eosin（HE） staining and periodic acid-Schiff（PAS） staining， the levels of gastrin（GAS） and motilin（MTL） in serum were detected by enzyme-linked immunosorbent assay（ELISA）， gas chromatography-mass spectrometry（GC-MS） was used to detect the contents of short-chain fatty acids（SCFAs） in mouse feces， real-time fluorescence quantitative polymerase chain reaction（Real-time PCR） and Western blot were used to determine the mRNA and protein expression levels of zonula occludens-1（ZO-1）， Occludin， and Claudin-1 in the colon of mice. ResultCompared with the blank group， the body mass， defecation frequency， fecal water content and intestinal propulsion rate of mice in the model group were significantly decreased（P<0.05， P<0.01）， the arrangement of colonic tissues was disordered， and the number of goblet cells was reduced， the levels of GAS and MTL in serum were significantly decreased（P<0.01）， and the levels of SCFAs in the feces were on a decreasing trend， with the contents of acetic acid， propionic acid， butyric acid， isobutyric acid and valeric acid were significantly decreased（P<0.05， P<0.01）， the mRNA and protein expression levels of ZO-1， Occludin and Claudin-1 in the colonic tissues were significantly decreased（P<0.01）. The above results suggested that STC mouse model was successfully constructed. Compared with the model group， the body mass， defecation frequency， fecal water content and intestinal propulsion rate of mice in AMP administration groups all increased significantly（P<0.05， P<0.01）， the mucosal layer of the colonic tissues was structurally intact without obvious damage， and the number of goblet cells increased， serum levels of GAS and MTL were significantly increased（P<0.01）， the contents of SCFAs in the feces were all on a rising trend， with the contents of acetic， propionic， butyric and isobutyric acids rising significantly（P<0.05， P<0.01）， the mRNA and protein expression levels of ZO-1， Occludin and Claudin-1 in the colonic tissues were significantly increased（P<0.05， P<0.01）. ConclusionAMR is able to improve the constipation symptoms in STC mice， and its mechanism may be related to increasing the contents of SCFAs in the intestine as well as promoting the mRNA and protein expression levels of ZO-1， Occludin and Claudin-1 in the colon.
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A derivatizaton method combined with gas chromatography-mass spectrometry(GC-MS)was established for detection of isobutyl chloroformate(IBCF)residue in active pharmaceutical ingredient of agatroban.The extraction and derivatization reagents,derivatization time,qualitative and quantitative ions were selected and optimized,respectively.The possible mechanism of derivatization and characteristic fragment ions fragmentation were speculated.The agatroban samples were dissolved and extracted by methanol,and the residual IBCF was derived with methanol to generate methyl isobutyl carbonate(MIBCB).After 24 h static derivatization at room temperature,IBCF was completely transformed into MIBCB,which could be used to indirectly detect IBCF accurately.The results showed that the linearity of this method was good in the range of 25-500 ng/mL(R2=0.9999).The limit of detection(LOD,S/N=3)was 0.75 μg/g,and the limit of quantification(LOQ,S/N=10)was 2.50 μg/g.Good recoveries(95.2%-97.8%)and relative standard deviations(RSDs)less than 3.1%(n=6)were obtained from agatroban samples at three spiked levels of IBCF(2.50,25.00,50.00 μg/g),which showed good accuracy of this method.Good precision of detection results was obtained by different laboratory technicians at different times,the mean value of spiked sample solution(25.00 μg/g)was 24.28 μg/g,and the RSD was 2.1%(n=12).The durability was good,minor changes of detection conditions had little effect on the results.Under the original condition and conditions with initial column temperature±5℃,heating rate±2℃/min,column flow rate±0.1 mL/min,the IBCF content of spiked sample solution(25.00 μg/g)was detected,the mean value of detection results was 24.16 μg/g,and the RSD was 2.2%(n=7).Eight batches of agatroban samples from two manufacturers were detected using the established method,and the results showed that no IBCF residue was detected in any of these samples.The agatroban samples could be dissolved by methanol,and then the IBCF residue could be simultaneously extracted and derived with methanol as well.This detection method had the advantages of simple operation,high sensitivity,low matrix effect and accurate quantification,which provided a new effective method for detection of IBCF residue in agatroban.
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Objective To investigate the characteristic volatile organic compounds(VOCs)in exhaled breath and their diagnostic value in mice with early stage radiation injury.Methods The thermal desorption gas chromatography-mass spectrometry(TD-GC/MS)technique was used to analyze VOCs in exhaled breath of irradiated mice by 60Coγ-ray with 800 cGy.The characteristic VOCs in the early stage of radiation injury were identified,and a diagnostic model was established.Results The 30-day survival rate of mice was 4.2%.There were significant differences in characteristic VOCs at 7 hours after radiation injury,and thirty characteristic VOCs related to early-stage radiation injury were identified.The diagnostic value of differential metabolites in mice after irradiation was evaluated via the ROC curve,and the area under the ROC curve(AUC)of a single compound exceeded 0.8.The diagnostic model was constructed by screening 9 potential biomarkers of exhalation through Fisher discriminant analysis,and its sensitivity and specificity were close to 100%.Conclusion Analysis of VOCs in exhaled breath is expected to provide a non-invasive diagnostic method for early screening and diagnosis of radiation injury.
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Objective To analyze the residual status,transfer behavior,and risk of paclobutrazole in the national mar-ket of Shenmai granules.Methods GC-MS/MS determined the residual amount of paclobutrazol in Shenmai granules,and ANOVA analyzed the distribution characteristics of sample residuals.The transfer rule of paclobutrazol from Ophiopogonis Radix to Shenmai granules was investigated by simulating the production process,and chronic exposure assessment was performed using the point evaluation model.Results The established method can accurately determine the residual amount of paclobutrazol in Shenmai granules.The residual amount of paclobutrazol in 85 batches of Shenmai granules ranged from 0.001 3 to 0.015 8 mg·kg-1,and there was a statistical difference in the residual amount among different enterprise samples.The transfer rate of paclobutrazol from decoction pieces to preparations was 29.8%.The chronic risk quotient(HQc)of paclobutrazol residues in Shenmai granules was 0.000 7%,far lower than 1.Conclusion There is a general presence of paclobutrazol residues in Shenmai granules.The risk assessment results show that the normal dosage of Shenmai granules does not pose an unacceptable risk to the general population.The residual distribution characteristics and process transfer rules can provide a reference for safety risk control in production enterprises.
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Objective To analyze the influence of different processing methods,including frying,ginger frying,and salt frying,on the volatile components of A.fructus.Methods The volatile components in different processed products of A.fructus were detected and analyzed by gas chromatography-mass spectrometry(GC-MS)based on multivariate statistical analysis.After OPLS-DA analysis,the different components were screened under the conditions of VIP＞1.5 and P＜0.05 and were qualitatively searched using the NIST 11 spectral library.Results A total of 49 different components were identified,with 14 components only changing in the seed mass and 22 components changing in the peel.The content of camphor could be significantly reduced in the seed mass after A.fructus was processed and the content of bornyl acetate significantly increased in the peel of frying A.fructus.Salt frying had a great influence on the alkanes in A.fructus,and ginger processing did not only increase the volatile components in ginger,which reflected the complexity of the processing mechanism.Conclusion At present,the specific processing mechanism is not clear,but the experimental results provide theoretical data for the "detoxification and efficiency enhancement" effect of A.fructus processing,reflecting the scientific nature of the processing,enriching the processing theory of A.fructus,and providing a reference for further in-depth research on the activity of different processed products of A.fructus.
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ObjectiveTo screen the differential markers by analyzing volatile components in Dalbergia odorifera and its counterfeits， in order to provide reference for authentication of D. odorifera. MethodThe volatile components in D. odorifera and its counterfeits were detected by headspace gas chromatography-mass spectrometry（HS-GC-MS）， and the GC conditions were heated by procedure（the initial temperature of the column was 50 ℃， the retention time was 1 min， and then the temperature was raised to 300 ℃ at 10 ℃ for 10 min）， the carrier gas was helium， and the flow rate was 1.0 mL·min-1， the split ratio was 10∶1， and the injection volume was 1 mL. The MS conditions used electron bombardment ionization（EI） with the scanning range of m/z 35-550. The compound species were identified by database matching， the relative content of each component was calculated by the peak area normalization method， and principal component analysis（PCA）， orthogonal partial least squares-discrimination analysis（OPLS-DA） and cluster analysis were performed on the detection results by SIMCA 14.1 software， and the differential components of D. odorifera and its counterfeits were screened out according to the variable importance in the projection（VIP） value>2 and P<0.05. ResultA total of 26， 17， 8， 22， 24 and 7 volatile components were identified from D. odorifera， D. bariensis， D. latifolia， D. benthamii， D. pinnata and D. cochinchinensis， respectively. Among them， there were 11 unique volatile components of D. odorifera， 6 unique volatile components of D. bariensis， 3 unique volatile components of D. latifolia， 6 unique volatile components of D. benthamii， 8 unique volatile components of D. pinnata， 4 unique volatile components of D. cochinchinensis. The PCA results showed that， except for D. latifolia and D. cochinchinensis， which could not be clearly distinguished， D. odorifera and other counterfeits could be distributed in a certain area， respectively. The OPLS-DA results showed that D. odorifera and its five counterfeits were clustered into one group each， indicating significant differences in volatile components between D. odorifera and its counterfeits. Finally， a total of 31 differential markers of volatile components between D. odoriferae and its counterfeits were screened. ConclusionHS-GC-MS combined with SIMCA 14.1 software can systematically elucidate the volatile differential components between D. odorifera and its counterfeits， which is suitable for rapid identification of them.
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ObjectiveTo discriminate the age of Arisaema Cum Bile， the combination of headspace solid-phase microextraction （HS-SPME） with gas chromatography-mass spectrometry （GC-MS） was applied to explore the differences of volatile components of unfermented， 1-year fermented， 2-year fermented， and 3-year fermented Arisaema Cum Bile. MethodSamples with different fermentation durations were collected and HS-SPME-GC-MS technology was employed to detect the volatile components of each sample. The relative contents of detected volatile components were processed and analyzed by chemometrics methods such as principal component analysis （PCA）， hierarchical cluster analysis （HCA）， and partial least squares discriminant analysis （PLS-DA）. ResultThe results showed that 145 volatile components were identified. Among these volatile components， the relative contents of heterocyclic， alcohols， aldehydes and aromatics were high. PCA， HCA， and PLS-DA can effectively separate Arisaema Cum Bile with four different ages. Based on variable importance in projection （VIP） value > 1， 73 markers of differential volatile components were identified. The content of 2，6，11-trimethyldodecane and m-xylene in unfermented samples was the highest， and the content difference between them and those in fermented samples was significant （P<0.05）. 2，3-butanediol was detected only in 1-year samples， octane was detected only in 2-year samples， and ethyl heptanoate was detected only in 3-year samples. These components can be used as odor markers for Arisaema Cum Bile with different fermentation years. ConclusionThe identification method of volatile components of Arisaema Cum Bile was established by HS-SPME-GC-MS technology， which can realize the rapid identification of unfermented， 1-year fermented， 2-year fermented， and 3-year fermented samples， and provide a scientific basis for the standardization of processing technology and quality standards of Arisaema Cum Bile.
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Objective To analyze the metabolic changes of myocardial tissue in rats under acute exposure to macleaya cordata by gas chromatography mass spectrometry(GC-MS),explore forensic identifications of its characteristic metabolites,and verify its toxicological mechanism in poisoning cases.Methods The rats in the exposure group were given 382 mg/kg macleaya extract solution by gavage,and the rats in the control group were given the same dose of solvent.The myocardial samples were analyzed by GC-MS,and pattern recognition was conducted through partial least squares discriminant analysis(PLSDA).The differential metabolites with characteristic changes were identified by variable importance projection(VIP value＞1)and Student's t test(P＜0.01).Results Compared with the control group,21 potential characteristic metabolites were identified.Through KEGG pathway enrichment analysis,it was found that these metabolites were mainly involved in the pathways of glycine,serine and threonine metabolism;pyruvate metabolism and glycerolipid metabolism.Conclusion Through the study of myocardial metabolism in rats exposed to macleaya cordata,we found the information on metabolites closely related to poisoning,which provides new insight and reference for studies on the mechanisms of macleaya cordata poisoning in the field of forensic medicine.
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Objective To analyze and identify the volatile constituents in different parts(flowers,stems and leaves)of Huai chrysanthemumin,and to lay a theoretical foundation for the comprehensive utilization for it.Methods The volatile oil in different parts of Huai chrysanthemumin were extracted by hydrodistillation,respectively.Their constituents were analyzed by gas chromatography-mass spectrometry(GC-MS).The compounds were identified by library search and literature screening.The relative percentage of each compound was obtained by the area normalization method.The differences in their chemical compositions were analyzed by Venn diagram,principal component analysis(PCA)and cluster heat map analysis.Results A total of 62 volatile chemical components were identified from different parts of Huai chrysanthemumin,including monoterpenes,sesquiterpenes,and their derivatives,as well as a small amount of aliphatic compounds.32,42 and 40 volatile components were detected from the flowers,stems and flowers,respectively.Furthermore 17 volatile components were shared by three parts,whereas 5,6 and 16 volatile components were unique to the flowers,stems and leaves,respectively.The results of stoichiometric analysis showed that both PCA and cluster heat map analysis could separate the flowers,stems and leaves,and their volatile components were different.Conclusion The types and contents of the volatile oil in the stems,leaves and flowers of Huai chrysanthemumin have certain variability,which provide a scientific basis for the further medicinal or industrial exploitation of different parts of Huai chrysanthemumin.
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ObjectiveTo investigate the key compounds affecting the irritation and to clarify the effect of heating and the addition of ginger juice as the auxiliary material during the processing on the irritation of Magnoliae Officinalis Cortex（MOC） by comparing the irritation and composition of volatile oil in MOC and its different processed products. MethodVolatile oil in raw products， water-processed products， ginger-dried products， ginger-fried products（the amounts of ginger were 10%， 50%， respectively） of MOC were extracted by steam distillation and subjected to rabbit eye irritation experiment， and the volatile components of each sample were detected by gas chromatography-mass spectrometry（GC-MS）. Principal component analysis（PCA）and orthogonal partial least squares-discriminant analysis（OPLS-DA） were used to analyze the data of each sample by SIMCA 14.1. The relative contents of different processed products were compared two by two with those of and raw products or ginger-fried products， and the markers that might be related to the irritation were sorted out according to the principles of variable importance in the projection（VIP） value >1 and P<0.05， and the factors influencing the differences in irritation were analyzed. ResultCompared with the blank group， the administration groups all had irritation to the eyes of rabbits， and the degree of irritation was in the order of raw products>water-processed products>ginger-dried products>ginger-fried products（10%）>ginger-fried products（50%）. The results of PCA and OPLS-DA showed that there were differences in the volatile oil from raw products and different processed products. According to VIP value>1 and P<0.05， and combined with the results of eye irritation experiment， ten volatile compounds related to irritation changes were screened out. Among them， cis-cinnamaldehyde was only detected in raw products， the relative contents of β-caryophyllene， （+）-delta-cadinene， α-humulene， γ-muurolene， （-）-isoledene and citral all increased to different degrees， the contents of p-cymene， 1（10）-4-cadinadien-15-ol and β-eudesmol all decreased to different degrees. ConclusionThe irritation of MOC is reduced after heating and processing with ginger juice， and the synergistic effect of both is more effective for reducing irritation. Among the differential markers associated with changes in irritation， the increase in the relative content of citral is closely related to the addition of ginger juice， while the decrease in the relative contents of cis-cinnamaldehyde， p-cymene， 1（10）-4-cadinadien-15-ol is related to heating， and the changes of other components may be related to the synergistic effect of heating and ginger juice.
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ObjectiveBy exploring the volatile components， polysaccharide composition and changes in the contents of five carbohydrate components of Polygonatum cyrtonema rhizoma before and after processing， and then the effect of yellow rice wine on the odour formation of P. cyrtonema rhizoma was investigated. MethodThe volatile components of P. cyrtonema rhizoma before and after processing were detected by headspace gas chromatography-mass spectrometry（HS-GC-MS）， and sample data were subjected to principal component analysis（PCA） and orthogonal partial least squares-discriminant analysis（OPLS-DA） using SIMCA 14.1， then the differences between these components of P. cyrtonema rhizoma before and after processing were screened according to the principle of variable importance in the projection（VIP） value>1. Crude carbohydrate components in raw and wine-processed P. cyrtonema rhizoma were subjected to oxime and silylation， the carbohydrate components were analyzed by gas chromatography-mass spectrometry（GC-MS/MS）， and the relative contents of various components were calculated by peak area normalization， then quantitative analysis of four carbohydrate components was also carried out. ResultA total of 23 volatile components were identified from the raw products and the wine-processed products， including 15 components in raw products and 20 components in wine-processed products. Among them， 2-methylbutyraldehyde and isovaleraldehyde had a sweet odor and their contents increased after processing， but the contents of hexanal and caproic acid decreased， new components such as 2-acetylfuran and 5-methylfuranal were produced after processing. PCA and OPLS-DA results showed that there were significant differences between raw products and the wine-processed products， a total of 13 differential compounds were screened out， of which 7 showed an upward trend in relative content and 6 showed a downward trend. A total of 7 carbohydrate components， including 5 monosaccharides and 2 disaccharides， were identified in raw products and the wine-processed products. The results of determination showed that the contents of fructose， glucose， mannose and sucrose in P. cyrtonema rhizoma increased after wine-processing， and their increases were 4.54， 1.51， 2.93， 3.66 times， respectively. ConclusionAfter processing， the increase of aromatic flavor of P. cyrtonema rhizoma may be related to the increase of the contents of aldehydes such as 2-methylbutyraldehyde and isovaleraldehyde， while the decrease of raw flavor may be related to the decrease of the contents of volatile components such as hexanal and hexanoic acid， the increase of sweet flavor may be related to the increase of the contents of monosaccharides and oligosaccharides such as fructose and sucrose.
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OBJECTIVES@#To establish the GC-MS qualitative and quantitative analysis methods for the synthetic cannabinoids, its main matrix and additives in suspicious electronic cigarette (e-cigarette) oil samples.@*METHODS@#The e-cigarette oil samples were analyzed by GC-MS after diluted with methanol. Synthetic cannabinoids, its main matrix and additives in e-cigarette oil samples were qualitatively analyzed by the characteristic fragment ions and retention time. The synthetic cannabinoids were quantitatively analyzed by using the selective ion monitoring mode.@*RESULTS@#The linear range of each compound in GC-MS quantitative method was 0.025-1 mg/mL, the matrix recovery rate was 94%-103%, the intra-day precision relative standard deviations (RSD) was less than 2.5%, and inter-day precision RSD was less than 4.0%. Five indoles or indazole amide synthetic cannabinoids were detected in 25 e-cigarette samples. The main matrixes of e-cigarette samples were propylene glycol and glycerol. Additives such as N,2,3-trimethyl-2-isopropyl butanamide (WS-23), glycerol triacetate and nicotine were detected in some samples. The content range of synthetic cannabinoids in 25 e-cigarette samples was 0.05%-2.74%.@*CONCLUSIONS@#The GC-MS method for synthesizing cannabinoid, matrix and additive in e-cigarette oil samples has good selectivity, high resolution, low detection limit, and can be used for simultaneous qualitative and quantitative analysis of multiple components; The explored fragment ion fragmentation mechanism of the electron bombardment ion source of indole or indoxamide compounds helps to identify such substances or other compounds with similar structures in cases.
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Cromatografía de Gases y Espectrometría de Masas/métodos , Sistemas Electrónicos de Liberación de Nicotina , Drogas Ilícitas/análisis , Indazoles/química , Glicerol/análisis , Cannabinoides , Indoles/química , IonesRESUMEN
@#[Objective] To explore the application of Quality by Design (QbD) tools in assessing geographical variations of Phyllanthus emblica (P. emblica) from five distinct Indian states. [Methods] In the current experiment, the Box-Behnken design with a reduced quartic model and 105 runs was employed with the use of the Design Expert software for randomized response surface mapping. Three different extraction methods (Soxhlet, maceration, and sonication) along with three solventst [distilled water, methanol, and water-methanol mixture (50 : 50 v/v)] were considered in the present study. The anti-oxidant activities, total flavonoid content (TFC), and total phenolic content (TPC) in the P. emblica were determined and analysed by gas chromatography-mass spectrometry (GC-MS) to identify the major components. [Results] The QbD overlay plot showed that the extractive value of the P. emblica was no less than 30% w/w, 2,2-diphenyl-1-picrylhydrazyl (DPPH) no less than 60% mcg/mL (micrograms per millilitre), TFC no less than 75 mg QE/g (milligrams of quercetin equivalents per gram), and TPC no less than 80 mg GAE/g (milligrams of gallic acid equivalents per gram). Moreover, the GC-MS data confirmed the presence of variation in the bioactives of P. emblica extracts. [Conclusion] The model was significant in describing the variation in extractive value, DPPH, TFC, and TPC. The QbD approach may tend to prioritize thoroughness in the extraction process, ultimately resulting in improved quality in the extracted products.
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Objective To establish a rapid qualitative analysis method for volatile organic components in chemicals. Methods Headspace gas chromatography-mass spectrometry was used to qualitatively determine 19 volatile organic components, including benzene, 1,2-dichloroethane, and n-hexane, in chemicals. Different sample amounts, heating temperatures, heating times, and sample volumes were analyzed to assess their effects on detection results and optimize sampling conditions. Results Based on the set chromatography, the optimal sampling process of this method was as follows： 5.0 g sample in a 20.0 mL headspace bottle, incubated at 40 ℃ for 30 minutes in a constant-temperature drying incubator, and a 1.00 mL headspace gas injection. The within-run and between-run relative standard deviations of all components ranged from 0.00% to 21.05% and 0.00% to 33.33%, respectively. The samples stored in sealed glass containers were stable at room temperature for at least 60 days. Conclusion This method offers simplicity, good reproducibility, and stability, making it suitable for rapid qualitative analysis of volatile organic components in chemicals.
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ObjectiveBy comparing the differences in composition and content of volatile components between Atractylodis Macrocephalae Rhizoma（AMR）and bleaching AMR， bran-fried AMR and bran-fried bleaching AMR， the effect of processing with rice-washed water on the volatile components in AMR and bran-fried AMR were investigated. MethodHeadspace gas chromatography-mass spectrometry（HS-GC-MS）was used to determine the volatile components in raw products， bran-fried products and their processed products with rice-washed water. GC conditions were programmed temperature（starting temperature of 50 ℃， rising to 140 ℃ at 10 ℃·min-1， maintained for 5 min， then rising to 210 ℃ at 4 ℃·min-1）， splitting ratio of 10∶1， high purity helium as the carrier gas and a solvent delay time of 3 min. MS conditions were an electron bombardment ion source（EI） with an electron collision energy of 70 eV， ion source temperature of 230 ℃， and the detection range of m/z 20-650. The relative contents of the components were determined by the peak area normalization method， the obtained sample data were subjected to principal component analysis（PCA） and orthogonal partial least squares-discriminant analysis（OPLS-DA） by SIMCA 14.1 software， and the differential components of AMR and bleaching AMR， and bran-fried AMR and bran-fried bleaching AMR were screened according to variable importance in the projection（VIP） value>1 and P<0.05. ResultA total of 71 volatile components were identified， including 53 in AMR， 50 in bleaching AMR， 51 in bran-fried AMR， and 44 in bran-fried bleaching AMR. OPLS-DA results showed that there were significant differences between AMR and bleaching AMR， bran-fried AMR and bran-fried bleaching AMR， but not between AMR samples from different origins. The compound composition of AMR and bleaching AMR， bran-fried AMR and bran-fried bleaching AMR did not change， but the contents of monoterpenes and sesquiterpenes changed significantly. ConclusionSignificant changes in the contents of volatile components were observed in AMR and bleaching AMR， bran-fried AMR and bran-fried bleaching AMR， among them， 1，2-dimethyl-4-methylidenecyclopentene， 9，10-dehydro-isolongifolene， γ-elemene， zingiberene， atractylone， silphinene， modhephene and （1S，4S，4aS）-1-isopropyl-4，7-dimethyl-1，2，3，4，4a，5-hexahydronaphthalene can be used as candidate differential markers of volatile components of AMR before and after processing with rice-washed water.
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ObjectiveTo analyze the fingerprint of six pungent herbs based on the molecular connectivity index（MCI）and the matching frequency total statistical moment method， and to study the division and integration of the "imprinting template" of their volatile components， so as to find the common "imprinting template" characteristics of the pungent herbs. MethodThe volatile components of six pungent herbs were extracted by steam distillation， and their fingerprints were established by gas chromatography-mass spectrometry（GC-MS） with a programmed temperature increase（80 ℃ for 5 min， 5 ℃·min-1 to 200 ℃ for 5 min， 2 ℃·min-1 to 230 ℃ for 10 min）， a splitting ratio of 20∶1， an electron bombardment ion source（EI） and the detection range of m/z 35-650， and the average MCI and total statistical moment parameters of the fingerprints were calculated. Then the matching frequency method was used to classify， integrate and confirm the chromatographic peaks of the fingerprints of six pungent herbs. ResultThe average zero order， first-order and second-order MCI values of the volatile components of Pogostemonis Herba， Artemisiae Argyi Folium， Atractylodis Rhizoma， Asari Radix et Rhizoma， Magnoliae Flos and Schizonepetae Herba were 9.02， 5.28 and 5.05， respectively. The average values of peak number， total zero-order moment， total first-order moment and total second-order moment were 60， 169×107， 22.49 min and 36.82 min2， respectively. The 20 integrated imprinting templates were obtained by the matching frequency method for the six pungent herbs， among which three were common imprinting templates with the retention times of （25.97±0.21），（26.90±0.20），（31.64±1.24） min， respectively， and the representative components were valencene，β-elemene， caryophyllin， etc. ConclusionMCI combined the matching frequency total statistical moment can divide and integrate the characteristics of imprinting templates of six pungent herbs， and find their common chromatographic imprinting characteristics， which can provide a reference for the determination of effective substances of pungent herbs.
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The menace of drug resistant pathogens is increasing and their level of evading conventional antimicrobials is rising. It is therefore important to discover new antimicrobials to counter the current challenges. Our preliminary investigation identified Bacillus subtilis subsp. subtilis 168 isolated from soil sample sourced from a river bank in Abuja, Nigeria, as the most potent antibiotic-producing bacteria among the other identified producers. The current study screened for the antimicrobial activity of the extract and fractions of the isolate by broth microdilution method. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and the ratio of the MBC/MIC were determined. All the tested pathogens were susceptible to the ethyl-acetate extract (MIC between 28.70 mg/ml and 57.40 mg/ml). The extract displayed bactericidal activity against all tested pathogens (MBC/MIC between 1.00 and 2.00) while Proteus mirabilis was least susceptible. The extract was purified by vacuum liquid chromatography and the fractions challenged with pathogenic strains. The fraction E was the most potent (MIC between 0.09 mg/ml and 0.75 mg/ml) and also bactericidal against all the test microbes (MBC/MIC between 2.00 and 2.11). GC-MS analysis of the purified sub fraction obtained from fraction E identified 13 compounds with different Retention time and peak areas. Among these were three major compounds which include: (i) bis(2-ethylhexyl) phthalate (ii) 1,4-epoxynaphthalene-1(2H)-methanol, 4,5,7-tris(1,1-dimethylethyl)-3,4-dihydro- (iii) D:B-Friedo-B':A'-neogammacer-5-en-3-ol, (3.beta.)-. Our findings suggest that Bacillus subtilis subsp. subtilis 168 isolated locally could serve as a valuable source of lead compounds for pharmaceutical and biotechnological purposes.
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Objective:To analyze the liposoluble components and antioxidant capacity of Caryopteris tangutica. Methods:By using GC-MS, this paper analyzes liposoluble components of different positions of Caryopteris tangutica. By making the removal rate of free radicals with liposoluble components as the index, and making IC 50 as reference indicators to evaluate the antioxidant capacity of lipidsoluble extracts of different parts. Results:There are 31, 40 and 62 compounds identified in the liposoluble components of the stems, leaves and flower, among which unsaturated fatty acids account for the most. The different parts of Caryopteris tangutica all play the role of clearing DPPH and ABTS + free radicals, and the clearing rate of leaves was greater than that of flowers and stems. Conclusion:The unsaturated fatty acids in lipidsoluble components of Caryopteris tangutica are beneficial to the human body, and have antioxidant activity.
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Docosanol is the only US Food and Drug Administration(FDA)approved over-the-counter topical product for treating recurrent oral-facial herpes simplex labialis.Validated analytical methods for docosanol are required to demonstrate the bioequivalence of docosanol topical products.A gas chromatography/selected ion monitoring mode mass spectrometry(GC/SIM-MS)method was developed and validated for docosanol determination in biological samples.Docosanol and isopropyl palmitate(internal standard)were separated on a high-polarity GC capillary column with(88％cyanopropy)aryl-polysiloxane employed as the stationary phase.The ions of m/z 83 and 256 were selected to monitor docosanol and isopropyl palmitate,respectively;the total run time was 20 min.The GC/SIM-MS method was validated in accordance with US FDA guidelines,and the results met the US FDA acceptance criteria.The docosanol calibration standards were linear in the 100-10000 ng/mL concentration range(R2＞0.994).The recoveries for docosanol from the receptor fluid and skin homogenates were＞93.2％and＞95.8％,respectively.The validated method was successfully applied to analyze ex vivo human cadaver skin permeation samples.On applying Abreva?cream tube and Abreva?cream pump,the amount of doco-sanol that penetrated human cadaver skin at 48 h was 21.5±7.01 and 24.0±6.95 ng/mg,respectively.Accordingly,we concluded that the validated GC/SIM-MS was sensitive,specific,and suitable for quantifying docosanol as a quality control tool.This method can be used for routine analysis as a cost-effective alternative to other techniques.