最新刊期
卷 42 ， 期 11 ， 2023
- 摘要：In order to meet the needs of tracing and continuous monitoring of odor pollution in ambient air，an online odor pollutants monitoring system based on gas chromatography and spectral detection was developed. The functions and characteristics of the system were described in detail from both hardware and software. The response correction system of nitrogen phosphorus detector and sampling manifold were further developed. The test results show that the detection limit of the system is less than 0.1 nmol/mol，with the relative standard deviation of repeatability less than 2%，and the correlation coefficient of the calibration curve is more than 0.99（more than 0.999 for hydrogen sulfide and ammonia）. The application cases of the system for mobile monitoring pollution tracing and site continuous monitoring are also introduced. The results show that the online monitoring system of odor pollutants has good accuracy，stability and field application ability，and can meet the requirements of odor pollution monitoring.关键词：odor pollutants;online monitoring;gas chromatography;spectral detection;application
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发布时间：2023-11-10 - 摘要：In this paper，a new manganese/zirconium bimetallic organic framework（Mn/Zr-MOF） nanomaterial was designed and synthesized. Paramagnetic metal manganese and zirconium endow Mn/Zr-MOF with peroxidase-like activity，while zirconium can selectively recognize fluoride ion（F-）. Mn/Zr-MOF nanomaterial exhibits excellent peroxidase-like activity. It can catalyze the oxidation of 3，3'，5，5'-tetramethylbenzidine（TMB） with hydrogen peroxide to generate blue oxTMB，with a maximum absorption wavelength of 652 nm. If F- exists in the system，it can selectively bind with Zr and exerts inhibitory effect the catalytic activity of Mn/Zr-MOF，resulting in a lighter color in the system. The concentration of F- was negatively correlated with the absorbance at 652 nm，thus a colorimetric method for F- detecting was established. The linear range of the method was 0.40-5.0 mg/L，and the detection limit was 0.16 mg/L. The method was applied to the determination of F- in actual water samples，with recovery of 97.6%-106% and relative standard deviation of 0.27%-5.2%. The proposed method is fast，sensitive，and highly selective，holding great potential in actual sample analysis.关键词：metal-organic framework;fluoride;colorimetry;nanoenzyme;peroxidase-like activity
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发布时间：2023-11-10 - 摘要：In this study，a method for the analysis of perfluorinated and polyfluorinated substances（PFASs） in various types of cosmetics was established based on ultra high performance liquid chromatography and tandem mass spectrometry（UHPLC-MS/MS）. Lotion，cream，emulsion，gel and powder cosmetics were dispersed by saturated ammonium acetate-sodium chloride solution（containing 1% formic acid） and extracted by 1% formic acid-acetonitrile solution. Oil and wax-based cosmetics were dispersed by n-hexane and extracted by saturated ammonium acetate-acetonitrile solution（containing 0.001% ammonium hydroxide）. The extracts were separated on an Agilent RRHD Eclipse Plus Zorbax C18 column（3.0 mm×100 mm，1.8 μm），analyzed by electrospray ionization source（ESI） under multiple reaction monitoring（MRM） mode and quantified by the matrix-matched calibration. The optimal pretreatment method was confirmed by investigating the recoveries of 30 PFASs under different pretreatment conditions. The method showed a good linear relationship for 30 PFASs in the concentration range of 1-250 μg/L，and the correlation coefficients（r2） were 0.990 3-0.999 8. The limit of detection（LOD） and quantitation（LOQ） were 0.025-0.125 μg/g and 0.050-0.250 μg/g，respectively. The average recoveries of 30 PFASs ranged from 70.8% to 112%，with relative standard deviations（RSDs，n=6） of 0.50%-12%. The RSDs of the peak area of 30 PFASs in each matrix solution within 24 h were less than 10%. This method was applied to the detection of 88 cosmetics samples，and one positive sample was found，whose PFOA and PFOS contents were 4.7 μg/g and 1.4 μg/g，respectively. The method showed simplicity，rapidity，good accuracy and high sensitivity，which could provide technical support for the quality control and daily supervision of cosmetics.关键词：ultra high performance liquid chromatography-tandem mass spectrometry（UHPLC-MS/MS）;liquid-liquid extraction（LLE）;cosmetics;perfluorinated and polyfluorinated substances（PFASs）;perfluorinated compound
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发布时间：2023-11-10 - 摘要：The main chemical constituents in the leaves of Pluchea indica（L.） Less. were qualitatively analyzed with ultra-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry（UPLC-Q-TOF-MS/MS）. The analytes were separated on a Waters UPLC BEH C18（2.1 mm×100 mm，1.7 μm） by gradient elution，with acetonitrile-0.1% formic acid solution as the mobile phase，and then analyzed in both positive and negative ion modes. A total of 52 chemical constituents were identified by mass spectrometry database，fragmentation regularities of mass spectra，consulting literature reports，retention time and mass data of reference compounds，including 2 coumarins，15 flavonoids，16 phenylpropanoids，5 alkaloids，5 fatty acids，3 organic acids，3 amino acids，1 phenolic acid，and 2 other compounds，of which 23 compounds were firstly reported for the leaves of Pluchea indica（L.） Less.，and 11 compounds were verified by reference substance. The method is accurate，reliable and efficient，which is suitable for rapid identification of ingredients in the leaves of Pluchea indica（L.） Less.，and can provide a basis for the pharmacodynamic mechanism and clinical application of the leaves of Pluchea indica（L.） Less..关键词：Pluchea indica（L.） Less.;leaves;UPLC-Q-TOF-MS/MS;chemical constituents;fragmentation rules
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发布时间：2023-11-10 - 摘要：The aim of this study was to investigate the mechanism of the total saponins of Panax japonicus on improving the lipid metabolism in HepG2 cells based on cell metabolomics. The HepG2 lipid deposition model was established with a 1 mmol/L free fatty acid mixture（oleic and palmitic acid at the proportion of 2∶1）. Oil red O staining and triglyceride analysis were carried out after 24 h of treatment with the total saponins of Panax japonicus（50 mg/L）. Total metabolites in HepG2 cells were extracted according to the improved Bligh-Dyer method and were further separated into polar and nonpolar fractions. Ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry（UPLC-Q/TOF MS） was used to detect and identify the metabolites. The Progenesis QI software was used to pre-process the data，such as baseline correction，peak alignment，peak recognition，peak extraction and peak normalization. The principal component analysis，orthogonal partial least squares discriminant analysis and volcano map analysis were used to screen the differential metabolites. Metabolic pathways were enriched by the MetaboAnalyst software. The results showed that the total saponins of Panax japonicas could significantly improve the lipid accumulation induced by oleic and palmitic acid in HepG 2 cells. 34 differential metabolites were identified in polar fraction，mainly including fatty acids and amino acids. 28 differential metabolites were identified from the nonpolar fraction，mainly including phosphatidylcholines，phosphatidyl ethanolamines and ceramides. These differential metabolites tended to return to normal levels after treatment with the total saponins of Panax japonicus. Differential metabolites are mainly involved in three metabolic pathways，including sphingolipid metabolism，glycerol phospholipid metabolism and unsaturated fatty acid synthesis. This study elaborated the possible mechanism of the total saponins of Panax japonicus on ameliorating lipid accumulation induced by oleic and palmitic acid in HepG2 cells from the perspective of cell metabolism，which was closely related to the regulation of sphingolipid metabolism，glycerolipid metabolism，fatty acid metabolism and inflammatory response. This study provided a reference for the lipid-lowering effect study of the total saponins of Panax japonicus in vivo.关键词：total saponins of Panax japonicus;hepG2 cells;lipid metabolism;cell metabolomics;ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry
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发布时间：2023-11-10 - 摘要：The MOF@TiN-Ag/silver sol composite substrate was utilized as an active substrate for the surface-enhanced Raman spectroscopy（SERS） of theophylline. This study discusses the application of this composite substrate for surface-enhanced Raman technology in drug detection. Initially，titanium nitride nanotube arrays were fabricated using electrochemical anodic oxidation combined with ammonia reduction nitration method. Subsequently，TiN-Ag composite substrates were prepared through electrochemical deposition，and a metal-organic framework（MOF） coating layer was grown in situ to obtain MOF@TiN-Ag composite substrates. Theophylline was then added dropwise onto the composite substrates for SERS detection after being mixed with the silver sol. The results revealed that the MOF@TiN-Ag/silver sol composite substrate comprises three phases：face-centered cubic TiN，metal monolithic Ag，and cobalt-based MOF. Scanning electron microscopy results demonstrated that the TiN nanotubes have a regular structure，and Ag nanostructures are uniformly dispersed on the surface in a dendritic form. MOF particles serve as an isolation layer with a regular shape and cover the surface of TiN-Ag. The spherical silver sol nanoparticles are distributed on the MOF@TiN-Ag composite substrate. Due to the synergistic enhancement of silver nanoparticles and TiN-Ag composite substrate，coupled with the enrichment property of MOF，the composite substrate exhibits excellent SERS performance. It has a SERS detection limit for theophylline solution of 1×10-5 mol/L，demonstrating good detection performance. The prepared MOF@TiN-Ag/silver sol composite substrate expands the application of SERS in drug detection.关键词：TiN-Ag;MOF;silver sol;theophylline;SERS
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发布时间：2023-11-10 - 摘要：An electrochemical biosensor was developed for the detection of protein kinase A（PKA） activity based on dual signal amplification strategy of nanoparticle-based bio-barcode and hybridization chain reaction（HCR）. MoS2/AuNPs nanocomposite was used as modified nanomaterial for glassy carbon electrode（GCE）. Cysteine-labeled substrate peptide was self-assembled on modified GCE surface by Au-S bonds，which was phosphorylated in the presence of PKA and ATP. Nanoparticle-based bio-barcode of S1-AuNPs-Ab was linked to phosphorylated substrate peptide through specific affinity. The initiator strand S1 of S1-AuNPs-Ab probe opened the hairpin DNA（H1 and H2） structures and triggered a cascade of hybridization chain reaction. Methylene blue（MB） molecules were captured on HCR product，resulting in an enhanced electrochemical response signal and achieving quantitative analysis of PKA activity. The response current of electrochemical biosensor is proportional to PKA concentrations in the range of 10-3-20 U/mL，with a detection limit（S/N=3） of 3×10-4 U/mL. The proposed electrochemical biosensor exhibits good selectivity，reproducibility and stability，and could be applied for PKA activity assay in cell lysates samples，inhibitor screening and discovery of protein kinase related drugs.关键词：protein kinase A;nanoparticle-based bio-barcode;hybridization chain reaction;electrochemical biosensor
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发布时间：2023-11-10 - 摘要：A method for the determination of 18 synthetic cannabinoids in chocolate based on QuEChERS/high performance liquid chromatography-quadrupole-time of flight mass spectrometry was established. By optimization the type of extraction solvent，sample extraction and purification conditions，it was determined that 200.0 mg of chocolate was extracted by ultrasonic extraction with 1 mL of methanol for 10 min，and then the supernatant was purified by adding 0.05 g of C18 and 0.05 g of PSA. The separation was achieved on ZORBAX Eclipse Plus C18（3.0 mm×100 mm，1.8 μm） column with gradient elution of acetonitrile and 0.1% formic acid aqueous solution as the mobile phase. Quadrupole-time of flight high resolution mass spectrometry was used for detection. Eighteen synthetic cannabinoids were separated and detected within 11 min. Two pairs of isomers：5F-EMB-PICA and 5F-MDMB-PICA were resolved by chromatographic retention time and secondary mass spectrum fragments；5F-EMB-PINACA and 5F-ADB are resolved by secondary mass spectrometry fragments. 18 synthetic cannabinoids obtained good linear relations in concentration ranges of 1-200 μg/L with correlation coefficients not less than 0.997 0. The limits of detection were between 0.02 μg/L and 0.20 μg/L，and the limits of quantitation were between 0.07 μg/L and 0.66 μg/L. The recoveries of samples at spiked levels of 50，100 and 150 μg/kg were between 86.2% and 104%. The relative standard deviations（RSDs） of instrument was between 0.040% and 2.0%，the intra-day RSDs of method was between 0.32% and 3.0% and the inter-day RSDs of method was between 1.3% and 3.6%. This method has the advantages of high sensitivity，strong stability and fast analysis speed，and provide technical support for the safety supervision of chocolate products and the fight against synthetic cannabinoid drug crimes.关键词：high performance liquid chromatography-quadrupole-time of flight mass spectrometry;QuEChERS;chocolate;synthetic cannabinoids
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发布时间：2023-11-10 - 摘要：An ultra performance liquid chromatography-tandem mass spectrometric（UPLC-MS/MS） method was established for detecting 15 trace N-nitrosamine compounds in cosmetics. The final established method involved ultrasonic extraction of cosmetics using water or acetonitrile for different compounds. The samples were treated with potassium ferrocyanide-zinc acetate solution for precipitating macromolecules or saturated sodium chloride-acetonitrile for salting out. An Agilent Poroshell 120 SB-Aq（100 mm × 3.0 mm，2.7 μm） chromatography column was used for separation，followed by atmospheric pressure chemical ionization（APCI） source and multiple reaction monitoring mode detection in the isotope internal standard method for quantification. The result showed good linearity（r2>0.995） for the 15 N-nitrosamine compounds in their respective concentration ranges，with detection and quantitation limits of 5-15 ng/g and 15-45 ng/g，respectively. The average recoveries for the three cosmetic matrices（aqueous，emulsion，cream） at spiked levels of 25，50，100 ng/g were between 88.0% and 111%，with relative standard deviations（RSD，n=6） of 1.4%-9.8%. The method was applied to the detection of commercial cosmetics and N-nitrosodiethanolamine（NDELA） was detected in 13 batches，with one batch exceeding the limit. The strong specificity，high sensitivity，and good precision made the method could solve the problems of poor stability and easy interference of N-nitrosamine compounds，and was suitable for the trace determination of 15 N-nitrosamine compounds in cosmetics.关键词：N-nitrosamine compounds;cosmetics;ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）;atmospheric pressure chemical ionization（APCI） source
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发布时间：2023-11-10
Scientific Papers
- 摘要：Present work proposed multi-step wavelength selection methods based on scale invariant feature transformance（SIFT） algorithm of extracting features of spectra images to build robust near infrared spectra（NIRS） models for predicting total reduced sugar（TRS） in tobacco leaves. So that the models can be directly shared by multiple NIRS instruments and applied in long period. The SIFT method was firstly applied to select characteristic spectral points of Uc based on several representative spectra of primary samples. Then the spectral points with lower standard deviance of the sample spectra（SDSS） values were eliminated from Uc to obtain important characteristic spectral points of Uic. The two-step wavelength selection method was named as SIFT-SDSS. Furthermore，the moisture-unsensitive（MUS） wavelengths were selected from Uic to get important and stable characteristic spectral points of Uisc. The three-step wavelength selection method was named as SIFT-SDSS-MUS. The partial least square regression（PLSR） models for predicting TRS were established based on different wavelength sets by using 80% of 292 primary tobacco leaf samples according to their TRS concentration ranges as calibration set，which were harvested in 2011-2013. The results indicate that when the TRS model based on the wavelengths selected by the SIFT-SDSS method was transferred to six secondary instruments to predict TRS in another 77 samples harvested in 2011-2013，the mean of absolute relative errors（MAREs） obtained from the spectra tested on the six units were all below 6%，satisfying the internal control requirement of tobacco enterprises. For each year samples of 2014-2020 tested on 5 NIRS instruments，and each year samples of 2014-2019 tested on another NIRS instrument，the model built by the SIFT-SDSS can provide MARE lower than 6%. While MAREs of TRS in samples harvested in many years and tested on the 7 NIRS instruments，which were predicted by full-wavelength model and the model based on the SIFT were higher than 6%. The two models cannot be applied on multiple instruments in long period. The TRS model built by the SIFT-SDSS-MUS method has the fewest variables，but its transferability and long-time service ability is a little inferior to the model built by the SIFT-SDSS method. In conclusion，the TRS model established by important characteristic wavelength selection method of SIFT-SDSS is most robust，has strong interpretability and fast computation speed. It can be directly shared among seven NIRS instruments and continuously service on 6 instruments at least six years. The work amount on maintenance and transfer of the TRS model is therefore greatly reduced.关键词：multi-step wavelength selection;transfer of near infrared spectroscopy model;service life of the model;tobacco leaves;total reductive sugar;scale invariant feature transformance
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发布时间：2023-11-10 - 摘要：A novel vardenafil analogue was detected in a pressed candy by liquid chromatography-quadrupole time-of-flight mass spectrometry. The molecular structure and fragmentation law of the compound were inferred from the fragment ions identified by high-resolution mass spectrometry. Its structure was further confirmed by IR spectrum and NMR spectrum. The compound was finally identified and confirmed as O-propylvardenafil. Quantitative analysis was carried out by high performance liquid chromatography-tandem mass spectrometry with the external standard method. Results showed that there was a good linear relationship for the analyte in the range of 1.0-100 ng/mL，with correlation coefficient（r2）of 0.999 2.The limit of detection and limit of quantitation were 0.02 mg/kg and 0.05 mg/kg，respectively. Recoveries at low，medium and high spiked levels were ranged from 76.5%-104%，with relative standard deviations（RSDs） of 1.6%-5.1%. The method was applied to the detection of real samples. The results showed that 5 batches of candy including pressed candy and 3 batches of health wine were positive samples. This method is rapid，accurate and high sensitive，and can be used as an effective method for screening and identification of vardenafil analogue.关键词：vardenafil analogue;illegal addition;liquid chromatography-quadrupole time-of-flight mass spectrometry;foods
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发布时间：2023-11-10 - 摘要：d（GGA） trinucleotide repeats play an important role in the regulation of the expression of c-myb proto-oncogene. Four GGA repeats have proven to adopt an“unconventional”G-quadruplex（G4） including a 3’guanine tetrad（T） stacked onto a 5’guanine-adenine heptad（H）. Moreover，two d（GGA）4 form very stable inter-molecular G4 by stacking two T∶H G-quadruplexes on the heptad plane，resulting in a T∶H∶H∶T dimer. d（GGA） trinucleotide repeats have been frequently found from the genome of various organisms and suggested to have the structure-based functions. Thus，it is necessary to identify the folding structures of these sequences before studying their biological functions. In this work，d（GGA）4 was discovered can be made of highly active DNAzyme in the presence of hemin，which catalyze a rapid reaction visualized by naked eyes. This DNAzyme activity is related to its folding structure. Based on the finding，a visualization method was raised for the rapid identification of the folding structures by d（GGA） trinucleotide repeats. A total of 20 sequences with d（GGA） repeats that were flanked with different nucleotides or with various repeat numbers were investigated. 16 sequences that possessed high DNAzyme activity were revealed to adopt dimer with a large proportion by gel electrophoresis，yet 4 sequences with dramatically reduced or no DNAzyme activity were found nearly no G4 or assembled fractions. These results suggest the highly reliable for using DNAzyme assay to visualization the folding structures by d（GGA） repeats in real sequences，expanding the usage of DNAzyme assay for the detection of“unconventional”G4s.关键词：G-quadruplex;DNAzyme;hemin;aptamer;biosensor;visual detection
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发布时间：2023-11-10 - 摘要：An ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS） method was established for the simultaneous determination of 52 anti-infective drugs in cosmetics. After ultrasonic extraction with acetonitrile，the sample was eluted on Waters HSS T3 column（2.1 mm×100 mm，1.8 μm） with mobile phase consisted of 0.1% formic acid solution-0.1% formic acid acetonitrile. For quantitative analysis，the electrospray ionization source was applied to carry out the positive and negative ions scanning with multiple reaction monitoring（MRM） mode. Results showed that there were good linear relationships for 52 anti-infective drugs from 1 ng/mL to 50 ng/mL，with correlation coefficients（r） greater than 0.99. The limits of detection ranged from 1 to 10 µg/kg，and the limits of quantitation ranged from 3 to 35 µg/kg. The recoveries ranged from 81.2% to 116% at three spiked levels，with the relative standard deviations（RSDs） less than 10%. The method could be used for the determination of 52 anti-infective drugs in cosmetics，and provides a technical reference for the supervision and administration of prohibited addition of anti-infective drugs in cosmetics.关键词：ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）;cosmetics;anti-infective drugs;prohibited addition
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发布时间：2023-11-10 - 摘要：In this study，gas chromatography-quadrupole time-of-flight mass spectrometry（GC-QTOF MS） was used to obtain chromatographic data of 20 types of tobacco extracts，which were then subjected to component analysis. A binary vector datasets were constructed for the purpose of classification. By employing the random forest model and optimizing experimental conditions，the identification of three categories of substances（extract，essential oil，and extractum） in tobacco extracts，as well as distinguishing tobacco extracts from six different geographical origins（A，B，C，D，E，and F），was achieved with recognition accuracy of 100%.关键词：GC-QTOF MS;random forest;tobacco extracts;category;geographicol origin;identification
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发布时间：2023-11-10 - 摘要：A method for the simultaneous determination of 18 kinds alkaloids including coriaria lactone，tripterygium wilfordii Hook.F，isoquinoline and pyrrolizidine（PAs） in honey samples was proposed by solid phase extraction/ultra performance liquid chromatography-tandem mass spectrometry（SPE/UPLC-MS/MS），and carried out preliminary risk assessment according to the research results. The honey samples were extracted with 0.1% formic water，and subsequently purified and enriched with a mixed solid phase extraction（Oasis MCX SPE） cartridge. Target analytes were separated on a Waters ACQUITY UPLCTM BEH Phenyl column（100 mm×2.1 mm，1.7 µm） by gradient mobile phase of 0.1% formic acid water and methanol. Alkaloids was detected under multiple reaction monitoring（MRM） in positive electrospray ionization mode，and quantified using the matrix-matched calibration curves. Good linear relations were obtained with correlation coefficient（r2） more than 0.993.The limits of quantitation（LOQs） were in the ranges of 0.05-25 µg/kg. The average recoveries for alkaloids in honey samples at three different spiked concentration levels ranged from 77.2% to 115%，with relative standard deviations（RSDs） not more than 12%. The method was used to analyze 40 honey samples，and the PAs were detected in 6 samples with content ranging from 1.09 µg/kg to 18.7 µg/kg，which indicated to be of potential health risk to human. Due to its advantages of high accuracy and good reproducibility，the proposed method could be applied to the simultaneous analysis of alkaloids in honey samples.关键词：medicine food homologous;solid phase extraction（SPE）;UPLC-MS/MS;honey;alkaloids;risk assessment
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发布时间：2023-11-10
Experimental Techniques and Methods
- 摘要：The leaves of the plant kratom tree are rich in alkaloids，of which the main alkaloid active ingredients，mitragynine and 7-hydroxymitragynine are polyopioid receptor agonists，and the excessive intake of kratom can cause drug dependence and even death. In recent years，kratom is increasingly abused worldwide，and has become the most widely used plant-based new psychoactive substance. Many countries have classified kratom as an illegal substance and conducted extensive research on its active ingredients. In this paper，the active ingredients of kratom，their pharmacological and toxicological properties and metabolic processes in vivo are introduced，and the latest progress of conventional testing methods such as gas chromatography-mass spectrometry，high performance liquid chromatography，liquid chromatography-mass spectrometry，as well as rapid detection methods such as mass spectrometry and immunoanalysis，for the detection of alkaloids active ingredients in kratom are reviewed，in order to provide reference for the accurate identification of the alkaloid active ingredients of kratom.关键词：kratom;active ingredients;alkaloid;metabolism in vivo;detection method;toxicology
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发布时间：2023-11-10
Review
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