Objective: To explore the fragmentation patterns of synthetic cannabinoids by electron impact (EI) ionization mass spectrometry. Methods: Forty synthetic cannabinoids were systematically investigated by gas chromatography coupled to mass spectrometry (GC-MS). Ionization mode was EI (70 eV) and the acquisition range was m/z 50-600. Results: According to the different structures of the “head group” and “linked group”, forty synthetic cannabinoids were divided into six categories, namely cumyl-carboxamide type, adamantyl-carboxamide type, carbamoyl/methyl butyrate-carboxamide type, naphthylformyl type, benzoyl/phenylacetyl type and tetramethylcyclopropane-acyl type. Through the analysis of the mass spectrum of synthetic cannabinoids, the fragmentation pathways and characteristic ions of different types of synthetic cannabinoids were given. The main EI-MS fragmentation patterns of synthetic cannabinoids were that both sides of the carbonyl group in the “linking group” undergo α-cleavage, and the N atom on the indole/indazole parent nucleus was prone to γ-H rearrangement, and loss of a R₁. In addition, fragment ions m/z 116, 130, 144 and fragment ions m/z 117, 131, 145 were the characteristic fragments of indazole and indole parent nucleus, which could be used to identify the parent nucleus of synthetic cannabinoids. Conclusion: These kind of compounds have strong fragmentation regularity. When standard substances are lacking or commercial mass spectral libraries are difficult to obtain, the proposed synthetic cannabinoids EI-MS fragmentation pathways can help to rapidly identify the structures of unknown synthetic cannabinoids.

Objective: To analyze the fractions and relative contents of volatile oils of Magnoliae Flos at different harvesting periods, to elucidate the dynamic pattern of changes in the chemical composition of Magnoliae Flos at five harvesting periods, and to evaluate its antioxidant and antimicrobial activities. Methods: The volatile oils of Magnoliae Flos at five harvesting periods was extracted by water vapour distillation, and the chemical composition was analyzed by gas chromatography-mass spectrometry (GC-MS) technique, and the relative content of each constituent was calculated. The constituents of Magnoliae Flos at the five harvesting periods were analyzed by PLS-DA analysis, which was used in combination with the VIP value to screen out the differential compounds. The antioxidant activity of the volatile oil of Magnoliae Flos was determined by ferric ion reducing antioxidant power (FRAP) method, and its in vitro antimicrobial activity was investigated by 96-well plate method. Results: The total volatile oils content of Magnoliae Flos was the highest in samples at the 4th harvesting period (10 February 2023). Thirty-eight components were identified in the volatile oils of Magnoliae Flos, and 12 differential compounds were screened, including γ-muurolene, elemene, δ-cadinene and α-terpineol, etc. The relative contents of γ-muurolene, alloaeromadendrene, borneol, camphor and cis-4-thujanol were the largest in samples at the 4th harvesting period, which was basically in line with the trend of the change of volatile oil content. The volatile oils in samples at five harvesting period showed certain antioxidant and antibacterial activities. And that in samples at the 4th harvesting period showed the strongest antioxidant activity and the inhibition ability against all five species of bacteria. Conclusion: The chemical composition of the volatile oils in Magnoliae Flos was basically the same in in samples at five harvesting periods, but there is a significant difference in the relative content of its volatile components in each harvesting period, and it is presumed that the beginning of February is the optimal harvesting period for Magnoliae Flos.

Objective: To investigate the flavor components of Epimedium extract and analyze pyrolysis products of the extracts from Epimedium. Methods: Ultra fast gas phase electronic nose was adopted to analyze volatile components in ethanol extracts of Epimedium and the alcohol extracting process of Epimedium was optimized by orthogonal experiment. Epimedium extract was pyrolysed to simulate cigarette smoking by TG-GC-MS. The lysates of Epimedium extract were analysed in a nitrogen environment, and the possible lysate mechanism of the products was reasonably speculated. Results: 22 volatile components were detected in the ethanol extracts of Epimedium at different concentrations. Concentration of Epimedium extracted with 60% ethanol was superior than others. Analyzing pyrolysis products of Epimedium extract, 78 compounds were identified at 150, 300 and 450 ℃, including aldehydes, ketones, alcohols, phenols, furans and benzene series. Conclusion: Ethanol extraction of Epimedium contains many aromatic volatile components. A large number of ketones, alcohols, phenols, furans and other volatile aroma compounds are produced after pyrolysis of Epimedium extract.

Objective: To establish an UHPLC-MS/MS method for determining eight primary components （catechin, epigallocatechin, rutin, quercitrin, epicatechin, (+)-dihydromyricetin, myricitrin and dihydroqurcetin） in the young branches and leaves of Xanthoceras sorbifolia Bunge, a medicinal plant from Mongolia, and to compare their contents in samples at different growth stages. Methods: A Waters CORTECS C₁₈ (100 mm×2.1 mm, 1.6 μm) chromatographic column was adopted using the mobile phase comprised of water containing 0.1% formic acid (A) and acetonitrile (B) with gradient elution（0-1 min, 5% B; 1-10 min, 5% B→28% B; 10-11 min, 28% B→95% B; 11-14 min, 95% B; 14-15 min, 95% B→5% B） at a flow rate of 0.3 mL·min^-1. The temperature of the column was set at 40 ℃. Injecting volume was 2 μL. Detection was conducted using electrospray ionization (ESI) in negative ion mode with multiple reaction monitoring (MRM). Results: The linearity of the eight chemical components was found to be excellent in the tested concentration ranges, with correlation coefficients above 0.997 6. Precision, repeatability and stability were satisfactory and the average recoveries were between 97.4% and 106.0% with RSDs≤5.0%. In six batches of leaves, contents of catechin, epigallocatechin, rutin, quercitrin, epicatechin, (+)-dihydromyricetin, myricitrin and dihydroqurcetin were in the ranges of 0.090-0.904 mg·g^-1, 0.093-2.258 mg·g^-1, 0.001-0.005 mg·g^-1, 0.530-6.176 mg·g^-1, 0.158-1.561 mg·g^-1, 0.002-0.056 mg·g^-1, 4.008-10.218 mg·g^-1 and 1.049-16.990 mg·g^-1, respectively. In six batches of young branches, the contents ranged from 0.384-1.025 mg·g^-1, 0.911-2.427 mg·g^-1, 0.008-0.127 mg·g^-1, 0.870-2.295 mg·g^-1, 0.659-1.746 mg·g^-1, 0.125-1.079 mg·g^-1, 2.296-4.681 mg·g^-1 and 1.958-4.946 mg·g^-1, respectively. The contents of eight components varied a lot in samples from different parts. The contents of myricitrin, rutin and quercitrin in the leaves exhibited noticeable changes with the growth cycle, suggesting their potential as quality control markers for leaves of Xanthoceras sorbifolia. Conclusion: The method is accurate, sensitive, stable, repeatable, and suitable for simultaneous determination of eight components in Xanthoceras sorbifolia Bunge, offering reference for quality control of its leaves and branches.

Objective: To establish a liquid-liquid extraction liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of the concentration of glycyrrhizic acid and glycyrrhetinic acid in human plasma. Methods: Glycyrrhizic acid, glycyrrhetinic acid and the internal standard Apixaban-¹³C-d₃(IS) were added to 0.1 mL of human blank plasma. 50 μL of ionization reagent (20% formic acid solution), 490 μL of ethyl acetate and 210 μL of methyl tert-butyl ether were used as extractant. The supernatant was dried by nitrogen, and the residue was dissolved with 200 μL acetonitrile-water (1∶1) containing 0.2% formic acid. And 5 μL of resulting solution was injected to the LC-MS/MS for analysis. Chromatographic conditions: the saparation was performed on a Boston Μni C₁₈（50 mm×2.1 mm, 3 μm）column with mobile phase consisting of 0.2% formic acid aqueous solution（mobile phase A）and 0.2% formic acid acetonitrile solution（mobile phase B）by gradient elution. The flow rate was 0.6 mL·min^-1, the temperature of column was 40 ℃. The sample volume was 5 μL, and the temperature of the sampler was 4 ℃. Mass spectrometry conditions: multiple reaction montoring(MRM) was performed on a triple quadrupole mass spectrometer equipped with a ESI source in the positive mode. The detection ion pairs were m/z 823.4→453.3（glycyrrhizic acid）, m/z 471.4→189.0 （glycyrrhetinic acid）and m/z 464.3→447.1（IS） respectively. Results: The calibration curves were linear over the concentrion ranges of 0.5-80 ng·mL^-1 for glycyrrhizic acid and 2-800 ng·mL^-1 for glycyrrhetinic acid (r>0.99) in the plasma, the lower limits of quantifications (LLOQ) were 0.5 ng·mL^-1(glycyrrhizic acid) and 2 ng·mL^-1(glycyrrhetinic acid), respectively. Inter-and intra-batch precisions (RSDs) were less than 6.8%, and the accuracy ranged from 92.3% to 104.2%. The recovery rates of glycyrrhizic acid and glycyrrhetinic acid were about 28.0% and 40.0% separately, and the recoveries of IS were about 65.0%, the precision (RSDs) were less than 7.9%. The normalized matrix factors of glycyrrhizic acid and glycyrrhetinic acid were about 1, and the precision (RSDs) were less than 7.3%. Conclusion: The method is sensitive, accurate, simple, rapid and applicable to simultaneous determination of the concentration of glycyrrhizic acid and glycyrrhetinic acid in human plasma.