最新刊期
卷 41 ， 期 11 ， 2022
- 摘要：An efficient early detection framework for glutaric acidemia type Ⅰ（GA-Ⅰ） was developed by utilizing urinary metabolomics analysis based on gas chromatography-mass spectrometry（GC－MS） coupled with chemometrics，aiming to overcome small samples and high dimension modeling problems．In the proposed framework，assisted by the capability of partial least squares discriminant analysis（PLS－DA） in collinearity processing and data interpretation，bootstrap was introduced to perform data perturbation and induce multiple base classifiers，integrating their feature selection strengths and forming a novel algorithm of BS－PLSDA．Based on three informative vectors of loading weights（LW），variable importance in the projection（VIP） and significance multivariate correlation（sMC），the formed novel algorithm BS－PLSDA enabled the screening of discriminative features that were so strong to survive across multiple base classifiers．Investigated by GC－MS urinary metabolomic profiling of GA－Ⅰ，the results showed that BS－PLSDAs of three informative vectors all outperformed their corresponding PLS－DAs modeled by single classifier in selection stability，even if the ratio of sample partitioning was altered from 7∶3 to 6∶4，gradually increasing the sample difference among training sets．When the ratio of sample partitioning was 7∶3，the Kuncheva index of BS－VIP－PLSDA could reach to 0.807 5．Furthermore，the screened stable discriminative features exhibited close biological correlations to the metabolic mechanism of GA－Ⅰ，in which several reported diagnostic organic acids were searched．Meanwhile，they yielded desired predictive powers that the averages of area under receiver operating characteristic curve（AUC） were 0.773 9，0.854 8 and 0.847 1，while Matthews correlation coefficient（MCC） were 0.671 9，0.783 8 and 0.801 3 for BS－LW－PLSDA，BS－VIP－PLSDA and BS－sMC－PLSDA，respectively．Finally，a comparison was performed between PLS－DA and support vector machine recursive feature elimination（SVM-RFE）．Equipped with the same ensemble feature selection strategy，the model BS－RBF－SVMRFE using nonlinear radial basis function（RBF） was superior to BS－PLSDAs in classification performance．Nevertheless，it obtained poor model interpretability．All the results revealed that the proposed BS－PLSDA exhibited its modeling feasibilities both in classification performance and data interpretation，resulting in good meet in clinical demand．It suitably guided the early detection，and aided clinical diagnosis and disease mechanism understanding for GA－Ⅰ.关键词：glutaric acidemia type Ⅰ;early detection;gas chromatography－mass spectrometry;partial least squares discriminant analysis;bootstrap;stable feature selection
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发布时间：2023-01-04 - 摘要：In this work，a label-free electrochemical sensor for microRNA－21 detection was reported，based on target-mediated self-assembly of DNA nanostructure and catalytic signal amplification．A thiol-tethered and stem-loop structured DNA capture probe（CP） and two sequence-specific DNA strands that were partly complementary to the CP and the target（microRNA－21） were used．Initially，the CP formed self-assembly monolayer on the surface of gold electrode vis Au－S chemistry，which further evolved to a H-shaped DNA－RNA complex in the presence of the target．The electroactive ions－［Ru（NH3）6］3+ （RuHex） electrostatically adsorbed to the negatively charged phosphate moieties in the nucleic acid skeleton could generate strong electrolytic current through DNA-mediated electron transfer mechanism．By contrast，the current signal was rather weak in the absence of the target，due to the inexistence of the DNA－RNA complex．Furthermore，another electroactive specie，［Fe（CN）6］3- ions were ultilized to chemically oxidize the electroreduction product－［Ru（NH3）6］2+ ions，thereby establishing an electrochemistry－chemistry cascade reaction and consequently realizing current signal amplification．Electrochemical impedance spectroscopy（EIS） was used to confirm the as-assembled DNA－RNA complex，and chronocoulometry technique was employed to calculate the capture probe density that may affect the electrochemical response．In addition，capture probe concentration，ratio and self-assembly time were optimized．The peak currents measured from differential pulse voltammetry（DPV） were proportional to the target concentration in the range of 0.1 fmol/L－0.1 nmol/L，with a detection limit down to 12.8 amol/L．Particularly，it could effectively distinguish other microRNAs and even single-base mismatch analogs，enabling to the detection of microRNA－21 in diverse cell lines．With the advantages of high sensitivity，favorable specificity and broad linearity，the reported sensor could work without the need of electrochemical probe labeling，and circumvents currently prevailing strategies such as PCR，rolling circle amplification and strand displacement reaction that are typically time-consuming and labor-intensive，sthus simplifying the analytical procedures and improving the practicality.关键词：nucleic acid self-assembly;electrochemical sensor;catalytic current;microRNA
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发布时间：2023-01-04 - 摘要：A gas chromatography－tandem mass spectrometry（GC－MS/MS） with solid phase extraction（SPE） was developed for the determination of 53 pesticides residues in phytocosmetics．The phytocosmetics samples were firstly extracted with acetonitrile，then the lipid substances in acetonitrile extract were removed by centrifugation under freezing condition．Concentration and clean-up steps were performed by solid phase extraction．After the pretreatment，the samples were separated on an Agilent VF－17ms capillary column（30 m × 0.25 mm × 0.25 μm），then detected by GC－MS/MS in selective reaction monitoring（SRM） mode and quantified by matrix-matched calibration．Results showed that there were good linear relationships for the 53 analytes with their correlation coefficients（r2） of 0.996 1－0.999 9．The limits of detection（LODs） and the limits of quantitation（LOQs） were in the range of 0.01－0.02 mg/kg and 0.02－0.05 mg/kg，respectively．The average recoveries for 53 pesticides in the samples ranged from 77.1% to 105%，with the relative standard deviations（RSDs，n = 6） of 0.50%－4.9%．The method was applied to the determination of 30 phytocosmetics samples，of which two positive samples were found．This method is simple，convenient，accurate and sensitive，which is suitable for the determination of 53 pesticide residues in phytocosmetics and could provide technical support for ensuring the quality and safety of cosmetics.关键词：gas chromatography－tandem mass spectrometry（GC－MS/MS）;solid phase extraction;phytocosmetics;pesticide residues
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发布时间：2023-01-04 - 摘要：Polycyclic aromatic hydrocarbons（PAHs） and organophosphorus flame retardants（OPFRs） are widespread and persistent organic pollutants in the environment．A high performance solvent extraction（HPSE）－solid phase extraction（SPE）/gas chromatography－mass spectrometry（GC－MS） was established for the determination of 16 PAHs and 15 OPFRs in atmospheric particulate matters．The extraction solvent of HPSE was n-hexane－dichloromethane（1∶1，by volume） solution．Meanwhile，other instrument parameters of HPSE（e.g．temperature and pressure） were also optimized．The extracts were concentrated by rotary evaporation，and then purified by Florisil solid phase extraction column．The eluents for PAHs and OPFRs were 10 mL of n-hexane－dichloromethane（1∶1） and 10 mL of ethyl acetate，respectively，and then the eluents were concentrated and determined by GC－MS．The linear ranges for 16 PAHs and 15 OPFRs were 0.001－2.0 μg/mL，and the correlation coefficients（r2） were greater than 0.99．The limits of detection（LODs，S/N = 3） for PAHs and OPFRs were 0.10－10.00 μg/L and 2.59－75.00 μg/L，respectively．The limits of quantitation（LOQs，S/N = 10） were 0.33－33.33 μg/L and 8.63－250.00 μg/L，respectively．The average recoveries for 16 PAHs and 15 OPFRs were in the range of 73.0%－98.0% and 69.3%－111%，with their relative standard deviations（RSDs） of 3.7%－13% and 2.5%－17%，respectively．The results showed that this method was suitable for the determination of PAHs and OPFRs in atmospheric particulate matter samples.关键词：high performance solvent extraction;solid phase extraction;gas chromatography－mass spectrometry;polycyclic aromatic hydrocarbons;organophosphorus flame retardants;atmospheric particulate matters
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发布时间：2023-01-04 - 摘要：The paper-based microfluidic chips are a kind of paper-based chips，which have the advantages of excellent performance，low price，safety and portability．However，the preparation technology for paper-based microfluidic chips mostly depends on the professional and expensive equipments，which limits their development to a certain extent．And it is not conducive to the commercialization process for paper-based microfluidic chips．In this paper，a paper-based microfluidic chip with hydrogel valve was developed by using a low-cost，simple home writing robot to draw a smart hydrogel with sensitive properties on a paper base．In order to verify the feasibility of the preparation method，Ca2+ was used as a model target．Results showed that the paper-based microfluidic chip prepared by this method could achieve the quantitative detection of Ca2+ solutions in the concentration range of 0.1－50 mmol/L with the naked eye，which has good usability and reproducibility．Meanwhile，a ILX506 CCD sensor was used to design and optimize the digital display device of the paper-based microfluidic chip so as to realize the automatic reading function for the measurement results of paper-based microfluidic chip．The experimental results showed that this method could be used for the rapid and convenient preparation of multiple paper-based microfluidic chips at low cost．The preparation method provides a new research idea for the ubiquitous preparation of paper-based microfluidic chips，which has a good promotion prospect in those developing regions.关键词：paper-based microfluidic chip;writing robot;hydrogel;rapid detection;visual quantitative detection
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发布时间：2023-01-04 - 摘要：An ultra-high performance liquid chromatography－tandem mass spectrometry（UPLC－MS/MS） was established for the simultaneous detection of 10 2C-series phenethylamines，i.e．2C－H，2C－D，2C－P，2C－T－2，2C－T－4，2C－T－7，25D－NBOMe，25C－NBOMe，25B－NBOMe and 25I－NBOMe in blood and urine samples．Comparing three preparation methods respectively，including precipitated protein（PPT），liquid－liquid extraction（LLE） and solid phase extraction（SPE），blood and urine samples were finally extracted by precipitated protein method with methanol．The chromatographic column and mobile phase were also optimized in this experiment．ACQUITY UPLC® BEH C18（100 mm × 2.1 mm，1.7 μm） was finally used as the analytical column to separate the targeted analytes with methanol－water（0.1% formic acid） solution as the mobile phase．The ion source of the tandem mass spectrometer was electrospray ionization（ESI），which was performed in multiple reaction monitoring（MRM） mode．There were good linear relationships for 10 target compounds in the range of 0.005－50 ng/mL，with the correlation coefficients（r2） of 0.995 8－0.999 9．The limits of detection（LODs） for 10 2C-series phenethylamines in blood and urine were in the range of 0.01－2 ng/mL and 0.002－5 ng/mL，respectively．At three spiked concentration levels of 1，5 and 20 ng/mL，the matrix effects for 10 target compounds in blood and urine were in the range of 71.9%－112%，and the recoveries ranged from 78.8% to 99.3%，with the intra-day and inter-day relative standard deviations（RSDs） both not more than 15%．This method is characterized by rapid analysis，simple operation，high detection sensitivity，small sampling amount，accurate results and good repeatability，and is suitable for the rapid determination of 2C-series phenethylamines in blood and urine.关键词：ultra-high performance liquid chromatography－tandem mass spectrometry;blood;urine;2C-series phenethylamines
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发布时间：2023-01-04 - 摘要：In order to enhance the adaptability of the near-infrared model，a near-infrared spectral model transfer method based on sparrow search algorithm combined with deep feedforward neural network（SSA－DFN） was proposed in this paper，aiming at the problem that the function transfer relationship between master and slave is difficult to determine due to the nonlinear interference caused by the difference between different stations and environmental factors．The depth feedforward network was used to fit the nonlinear function mapping between spectra collected with different instruments，and the sparrow search algorithm was used to initialize the connection weights and thresholds of each layer of the network．The optimal initial values of the connection weights and thresholds were obtained through iterative updating of individual positions in the population．By adjusting the super parameters of the depth feedforward neural network model many times，the network fitting effect tends to be optimal，and finally the transfer function is determined．To verify the effectiveness of this method，SSA－DFN method was compared with PDS and CCA before and after the transfer from the perspectives of near infrared spectrum，principal component projection and prediction results．The results showed that SSA－DFN method has the highest coincidence degree between the slave spectrum after transfer and the original host spectrum，and there is no significant difference in the prediction results of total sugar and nicotine content between the master and slave after transfer．The average prediction error decreased from 8.32% and 9.15% to 4.65% and 4.82%，respectively．The indexes such as RMSEP and R2 were better than PDS and CCA，which achieved the best transfer effect and met the needs of enterprises，indicating that this method is an effective model transfer method.关键词：calibration transfer;sparrow search algorithm;deep feedforward neural network;near infrared spectrum
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发布时间：2023-01-04 - 摘要：To realize the online analysis of heavy metal lead ion（Pb2+），a label-free aptamer electrochemical sensor was constructed with the hybridization indicator methylene blue（MB） as the electrochemical signal probe and the aptamer as the recognition element of Pb2+．On the surface of the gold electrode，the aptamer and its complementary sequence cDNA were successively modified to form a double strand，and then the MB adsorbed between the double strands produced a strong electrochemical signal．In the presence of Pb2+，the aptamer specifically captured Pb2+ and released MB，resulting in the decrease of the electrical signal so as to realize the quantitative detection of Pb2+．Electrochemical impedance spectroscopy and cyclic voltammetry were performed to characterize the successful development of the constructed aptamer electrochemical sensor，while the feasibility of the sensor was proved by PAGE gel electrophoresis analysis．Differential pulse voltammetry was applied to record the electroactive signal of MB in Tris－HCl buffer solution．After optimization，the optimal experimental conditions of the aptamer electrochemical sensor were as follows：incubation time of cDNA：120 min；concentration of MB：1.6 mmol/L；incubation time of MB：120 min；incubation time of Pb2+：60 min．The linear response range for the sensor to Pb2+ was 0.1－100 000 μg/L，and the limit of detection was as low as 33.4 ng/L．The results of the specificity test showed that the other interfered metal ions play a non-obvious effect on Pb2+ detection．The proposed method was applied to the determination of Pb2+ in milk samples and lake water samples．The spiked recoveries were in the ranges of 87.1%－115% and 106%－108%，with their relative standard deviations（RSDs） of 10%－13% and 5.0%－9.5%，respectively．The label-free aptamer electrochemical sensor constructed in this paper exhibits the advantages of low cost，sensitivity and rapidity，which is expected to be employed in the field analysis of Pb2+ in the environment and food industry.关键词：lead ion;aptamer;electrochemical sensor;hybridization indicator
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发布时间：2023-01-04 - 摘要：An ultra-high performance liquid chromatography－tandem mass spectrometric method （UPLC－MS/MS） was established for the determination of 24 kinds of phenolic acids and flavonoids in honey．The target compounds were extracted with water，then purified and concentrated with a SHIMSEN Styra MAX solid phase extraction column，and finally analyzed by UPLC－MS/MS and quantified by external standard method．Under the optimal conditions，there were good linear relationships for 24 target compounds in the range of 2－1 000 μg/L with correlation coefficients（r2） greater than 0.998．The limits of quantitation for the analytes were in the range of 2－10 μg/kg．The average recoveries ranged from 60.3% to 111%，with relative standard deviations of 0.80%－8.5%．The established method was successfully applied to the rapid detection of 15 samples from five types of honey．It was found that 18 compounds including gallic acid，pinobanksin，galangin，pinocembrine，protocatechuic acid，p-coumaric acid，p-hydroxybenzoic acid，caffeic acid，quercetin，isorhamnetin，kaempferol and chrysin etc．were detected in all honeys，but there existed significant differences in their contents．Meanwhile，rosmarinic acid and morin were undetected in all honeys．The method is simple，rapid，sensitive and stable，and it could be used for the simultaneous determination of various phenolic acids and flavonoids in various honeys.关键词：honey;ultra-high performance liquid chromatography－tandem mass spectrometry;solid phase extraction;phenolic acids;flavonoids
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发布时间：2023-01-04 - 摘要：Ferric ion with an abnormal concentration level can cause obvious body dysfunction，and even lead to Parkinson's disease，Alzheimer's disease and other serious diseases．Therefore，it is very important to develop an effective analytical method for the detection of Fe3+ in environmental samples and the dynamic monitoring of Fe3+ in cells for the maintenance of normal physiological function of human body．In this study，a series of beer-based fluorescent carbon dots（CDs） were synthesized by hydrothermal method using beers as carbon sources．The CDs synthesized with the self-brewed beer of Qilu university of technology had better luminous efficiency than those synthesized with other brands．The structure and optical properties of CDs were characterized by transmission electron microscopy（TEM），X-ray diffraction（XRD），Fourier transform infrared spectroscopy（FTIR），UV-Vis absorption spectroscopy（UV－Vis） and fluorescence spectroscopy．The results showed that the CDs were spherical monodispersed nanoparticles with a relatively narrow size distribution and an average diameter of 5.6 nm，which had an amorphous carbon structure and contained a large number of active functional groups such as C—N/C—O and C
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发布时间：2023-01-04 - 摘要：Ion mobility spectrometry（IMS） was used to analyze 20 kinds of counterfeit banknote paper in this article．The volatile components in counterfeit banknote papers were quickly detected by IMS，and the fingerprint spectrum library for counterfeit banknote paper was constructed．Based on principal component analysis（PCA） and hierarchical cluster analysis（HCA），the spectral information within the migration time range of 8－17.5 ms was processed，and then the counterfeit banknote papers were classified．PCA clustered the same kind of counterfeit banknote papers，while HCA further classified 20 kinds of counterfeit banknote paper accurately，and the classification accuracy rates for 6 counterfeit banknote papers of unknown origin reached 83.33%．It can help judge the source of paper used for counterfeiting．The results showed that the rapid IMS detection is an effective method for comparison and classification of counterfeit banknote papers.关键词：counterfeit banknote paper;ion mobility spectrometry（IMS）;principal component analysis（PCA）;hierarchical cluster analysis（HCA）
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发布时间：2023-01-04 - 摘要：An ultra liquid chromatography－quadrupole/electrostatic field orbitrap mass spectrometry（UPLC－QE－Orbitrap MS） with QuEChERS extraction was developed for the simultaneous determination of 10 new synthetic cannabinoids in blood．The whole blood samples were firstly extracted by optimized QuEChERS method，then separated on an Hypersil GOLDTM Vanquish column（100 mm × 2.1 mm，1.9 μm） by gradient elution，with 0.1% formic acid water and 0.1% formic acid acetonitrile as mobile phases，and finally determined with positive heated electrospray ion source（HESI+） in parallel reaction monitoring（PRM） mode．The results indicated that the calibration curves for 10 target compounds exhibited good linear relationships in their respective mass concentration ranges，with correlation coefficients（r2） not less than 0.999 0．The limits of detection（LODs） and limits of quantitation（LOQs） for 10 compounds were in the range of 0.01－0.05 ng/mL and 0.05－0.20 ng/mL，respectively．The recoveries for 10 compounds ranged from 92.1% to 115%，and the matrix effects ranged from 86.6% to 115%，with the intra-day relative standard deviations（RSDs） and the inter-day RSDs not more than 8.5% and 10%，respectively．The method has the advantages of simple operation，good selectivity，high sensitivity and recovery，and it is suitable for the identification of synthetic cannabinoids in whole blood samples.关键词：QuEChERS;UPLC－QE－Orbitrap MS;blood;new synthetic cannabinoid
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发布时间：2023-01-04 - 摘要：A novel sandwich-type electrochemical immunosensor was designed for quantitative detection of hepatitis B surface（HBs） antigen．SnO2 loaded graphene sheet hybridized by Au NPs（GS-SnO2－Au） was used as the platform．Platinum hybrid multiwalled carbon nanotubes adhered copper oxide（Pt@CuO－MWCNTs） was used as label．As the carrier material，GS－SnO2－Au has larger surface area，better electrical conductivity，dispersibility and biological compatibility，which is benefit for capturing antibodies（Ab1）．Pt，CuO and multiwalled carbon nanotubes could be used as catalysts for the decomposition of hydrogen peroxide，and Pt@CuO－MWCNTs could realize multiple amplified signals due to their synergy．The morphological characteristics of GS－SnO2－Au and Pt@CuO－MWCNTs were observed by transmission electron microscopy（TEM）．The results showed that the substrate material（GS－SnO2－Au） and the marker material（Pt@CuO－MWCNTs） have excellent properties．The synthesis of Pt@CuO－MWCNTs was further characterized by energy spectrum，and the element content was also analyzed．The assembly process of the immunosensor was characterized by cyclic voltammetry（CV） and alternating current impedance．The optimal conditions were as following：pH value of phosphate buffer solution was 7.4，concentration of GS－SnO2－Au was 1 mg/mL，and concentration of Pt@CuO－MWCNTs was 2 mg/mL．Under the optimal conditions，the designed immunosensor exhibited a wide linear in the range of 0.001－100 ng/mL with a low detection limit of 0.33 pg/mL for HBs．The spiked recoveries for HBs in serum samples were in the range of 99.8%－100% with relative standard deviations（RSDs） of 1.1%－1.5%．With good selectivity，reproducibility and stability，the designed immunosensor could provide potential applications in clinical monitoring of HBs.关键词：SnO2 loaded graphene sheet hybridized by Au NPs;Pt hybrid multiwalled carbon nanotubes adhered copper oxide;immunosensor;hepatitis B surface antigen
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发布时间：2023-01-04 - 摘要：In this study，an ultra-high performance liquid chromatography－tandem mass spectrometry for the rapid detection of ketamine in water was established，based on a magnetic solid-phase extraction technique with magnetic biochar as adsorbent．The magnetic biochar composites with excellent adsorption performance were prepared using the low-cost，environmentally friendly and renewable pomelo peels as biomass raw material，so as to achieve the efficient enrichment and purification of ketamine in water．The characterization results of scanning electron microscope and vibrating sample magnetometer both indicated that the magnetic biochar was successfully synthesized．The sample pretreatment conditions were optimized in detail．Single factor experiments were firstly used to optimize the experimental parameters affecting the extraction efficiency such as the dosage of adsorbent，adsorption time and pH value of solution．Box－Behnken design was further applied to investigate the effects of adsorbent proportion，desorption volume and desorption time on the recovery of ketamine in water．The results revealed that there was good linear relationship for ketamine in the concentration range of 1－100 μg·L-1 under optimal conditions，with correlation coefficient（r） larger than 0.999．The limit of detection of the method was 0.263 μg·L-1，and the limit of quantification was 0.878 μg·L-1．In different actual water samples，the recoveries at four spiked levels of 1，10，20 and 50 μg·L-1 ranged from 84.0% to 99.9%，with intra-day and inter-day relative standard deviations of 0.40%－3.4% and 0.25%－1.9%，respectively．The established method possesses the advantages of easy operation，high efficiency，accuracy，and sensitivity，which is suitable for the detection of ketamine in water.关键词：magnetic biochar;ultra-high performance liquid chromatography-mass spectrometry;ketamine;adsorption;water
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发布时间：2023-01-04
Scientific Papers
- 摘要：A solid-phase extraction（SPE）/ultra performance liquid chromatography－tandem mass spectrometry（UPLC－MS/MS） was developed for the determination of residues of fipronil（FIP） and its metabolites（FIPS），i.e．fipronil desulfinyl，fipronil sulfone and fipronil sulfide in rice fishing water．According to the complicated properties of the testing chemicals and the impurities of rice fishing water samples，a new type of filter membrane was selected for the pretreatment of water samples，and the following extraction method was successfully exploited after a series of preliminary experiments．Furthermore，the SPE conditions and nitrogen blowing temperatures were optimized to ensure the high efficiency of extraction and high purification quality of extraction．In brief，rice fishing water samples were firstly filtered by using glass fiber filter paper，then enriched and purified with Supelco ENVI－18 solid-phase extraction column，and finally eluted with acetonitrile．The target compounds were separated on a SB－C18 column（2.1 mm × 100 mm，1.8 µm），and subsequently determined using an electrospray ionization source in the negative ion multiple reaction monitoring（MRM） mode．The calibration curves for target compounds were linear in the range of 0.5－100 ng/mL with correlation coefficients（r2） more than 0.998．The limits of detection（LODs） and quantitation（LOQs） were 0.5 ng/L and 1.5 ng/L，respectively．The average recoveries for target compounds ranged from 81.6% to 105%，with relative standard deviations（RSDs） of 3.5%－7.0%．The proposed method was applied to the determination of FIP and FIPS in thirteen authentic water samples collected from the rice fishing areas，of which one was found containing fipronil and fipronil sulfone．The proposed method is simple，sensitive，cost-effective and efficient，and could provide technical support for the environmental monitoring and risk assessment of FIP and FIPS in rice fishing systems and their food products.关键词：ultra performance liquid chromatography－tandem mass spectrometry;solid-phase extraction;rice fishing water;fipronil and its metabolites
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发布时间：2023-01-04 - 摘要：An ultra high performance liquid chromatography－fluorescence detection（UPLC－FLD） method was developed for the simultaneous determination of 3 core kinds of sialic acids（SAs） including N-acetylneuraminic acid（Neu5Ac），N-glycolylneuraminic acid（Neu5Gc） and 2-keto-3-deoxynononic acid（KDN） in fish. The freeze-dried samples were acid hydrolyzed with 8 mL 0.6 mol/L hydrochloric acid solution for 20 min at 80 ℃，followed by derivatization with 4，5-dimethylbenzene-1，2-diamine（DMBA）．The derivative conditions for DMBA were optimized by single factor test．All the target compounds were separated on an Waters Acquity UPLC BEH C18 column（100 mm × 2.1 mm，1.7 μm） by gradient elution，using pure water and acetonitrile as eluents，then detected by UPLC－FLD．Under the optimized conditions，there were good linear relationships for Neu5Ac，Neu5Gc and KDN in the range of 0.02－5.0 μg/mL（r2 > 0.999），with their limits of quantitation（S/N = 10） of 0.20 μg/g，0.20 μg/g and 0.10 μg/g，respectively．The spiked recoveries for three SAs at three levels ranged from 90.8% to 103%，with relative standard deviations（RSDs） of 2.8%－5.0%．The analysis was rapid，and it could be achieved within 4 min with good separation and sharp peak shapes．With the characteristics of high accuracy and good precision，the method was suitable for the simultaneous determination of Neu5Ac，Neu5Gc and KDN in fish.关键词：sialic acids;ultra performance liquid chromatography;derivatization;fish
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发布时间：2023-01-04 - 摘要：Chinese star anise（Illicium verum） is used as a spice in Asian while it is used as herbal remedy for infantile colic in America or Europe．Toxic Illicium species such as Japanese star anise （Illicium anisatum L.），resembling Chinese anise star，contain higher concentrations of sesquiterpene lactone neurotoxin named anisatin．Consumption of Chinese anise star contaminated or adulterated by such toxic Illicium species may cause fatal poisoning．However，it is difficult to distinguish between Chinese star anise and its adulterants just according to dried fruit appearance due to the morphological similarity．Therefore，it is of great significance to establish a method to identify Chinese star anise from its adulterants to ensure food safety．The aim of this work was to establish high performance liquid chromatography－tandem mass spectrometry（HPLC－MS/MS） with a quick，easy，cheap，effective，rugged and safe（QuEChERS） pretreatment for the determination of anisatin in star anise．The sample was extracted with acetonitrile in acetate buffer system．Then the extracted supernatant was purified with 200 mg of primary secondary amine （PSA） and 50 mg of graphitized carbon black（GCB）．The chromatographic separation was carried out on an Accucore aQ C18 column（2.1 mm × 150 mm，2.6 μm） by gradient elution，using methanol and 0.1% formic acid aqueous solution as the mobile phases．Anisatin was detected in negative electrospray ionization（ESI－） mode under multiple reaction monitoring（MRM） mode，then quantified by external standard method．The result showed that the calibration curve for anisatin had a good linear correlation in the range of 1.0－100.0 ng/mL，with a correlation coefficient（r2） higher than 0.99．At the four spiked levels of 0.02，0.20，0.40 and 1.00 mg/kg，the average recoveries ranged from 92.5% to 112%，with the relative standard deviations（RSDs） from 1.1% to 6.0%．The limit of detection（LOD） and the limit of quantification（LOQ） were 0.006 mg/kg and 0.02 mg/kg，respectively．The established method was applied to the determination of anisatin in 10 batches of Chinese star anise samples purchased from the local market，of which 1 batch was found containing anisatin exceeding 1.00 mg/kg．The result indicated that there was a potential adulteration risk of Chinese star anise in the market．This proposed method is simple，rapid，sensitive and accurate，and it could provide a technical support for the quality evaluation and authenticity discrimination on Chinese star anise.关键词：star anise;anisatin;QuEChERS;high performance liquid chromatography-tandem mass spectrometry;quality assessment
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发布时间：2023-01-04 - 摘要：An enzyme-linked immunosorbent assay（ELISA） method based on the monoclonal antibody was established for determination of pesticide isoprothiolane．Two haptens were prepared by extending active arms of different lengths from disulfide heterocyclic pentane structure of isoprothiolane molecule．The two haptens were conjugated with carrier protein to obtain the immunogen and coating antigen．Monoclonal antibody，named mAb－DWL，against isoprothiolane was obtained via the procedures of mouse immunization，cell fusion，eluting sieve and ascites collection．Results showed that the ELISA based on the obtained mAb－DWL exhibited a linear range of 4.6－530.2 ng/mL，with an IC50 of 55.2 ng/mL．Meanwhile，the cross-reactivity rates for the mAb－DWL with other similar pesticides were lower than 1%．The spiked recoveries for isoprothiolane in the vegetables and grains samples ranged from 77.2% to 116%．The monoclonal antibody prepared by this method could be used for development of rapid method for isoprothiolane determination.关键词：isoprothiolane;monoclonal antibody;ELISA;pesticide
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发布时间：2023-01-04 - 摘要：An underivatization/liquid chromatography－tandem mass spectrometric method was developed for the determination of 4 organophosphorus amino acids herbicides in fruits and vegetables．Samples were firstly extracted with water－dichloromethane solution，then purified by dichloromethane liquid－liquid extraction with HLB solid phase extraction column，and finally determined by liquid chromatography－mass spectrometry．At the optimal conditions，the linear correlation coefficients（r） for all compounds were more than 0.996 in the concentration range of 0.010－0.200 mg/L．The limits of detection and quantitation of the method were 0.01 mg/kg and 0.05 mg/kg，respectively．The average recoveries for all compounds at spiked levels of 0.050，0.100 and 0.200 mg/kg ranged from 72.2% to 109%，with relative standard deviations（RSDs，n = 6） of 2.2%－11%．The method is rapid，simple，sensitive and accuracy，and it could be used for the determination and confirmation of organophosphorus amino acids herbicides in fruits and vegetables.关键词：underivatization;organophosphorus amino acids herbicides;liquid chromatography－tandem mass spectrometry
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发布时间：2023-01-04
Experimental Techniques and Methods
- 摘要：It is of great significance to use a simple，rapid and sensitive detection method to detect heavy metals in food．Screen-printed electrode（SPE） has obvious advantage in the field of rapid electrochemical analysis due to its characteristicis of small and portable，less sample consumption and low cost，and it could realize the rapid on-site analysis on heavy metals and other pollutants in food．The concept，manufacturing technology，preparation materials and modification materials of screen-printed electrode are mainly introduced in this paper．Meanwhile，the application and research progress of screen-printed electrode in rapid detection of heavy metals are summarized，and its current situation and future development trend are also discussed.关键词：screen-printed electrode（SPE）;heavy metals;food;detection
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发布时间：2023-01-04
Review
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