最新刊期
卷 38 ， 期 2 ， 2019
- 摘要：Aerolysin could self assemble and oligomerize heptameric complex which insert into the lipid bilayer to form a nanopore.Due to the electrochemically confined effects,the aerolysin shows the high sensitivity in single molecule analysis of DNAs.Here,aerolysin was used to directly discriminate the single acetylene linked deoxyribonucleoside triphosphates from a single oligonucleotide without label or PCR operations.After modifying with acetylene derivative,a single oligonucleotide produced seven times longer blockade duration inside an aerolysin nanopore,increasing the blockage current amplitude by 7% and narrowing the current distribution by 44%.Therefore,the modification of the linear side chain of acetylene derivative could be further used to improve the temporal and spatial resolution in single DNA analysis via the aerolysin nanopore.关键词：biological nanopore;single molecule analysis;DNA;electrochemically confined space
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发布时间：2023-04-18 - 摘要：A rapid method for the identification of sandalwoods was developed based on proton nuclear magnetic resonance（1H NMR）with pattern recognition such as clustering analysis，principal component analysis（PCA）and partial least squares-discriminant analysis（PLS-DA）to build the models of identification.The samples included 6 species of sandalwood，i.e.Dalbergia oliveri，Dalbergia bariensis，Dalbergia cochinchinensis，Pterocarpus erinaceus，Pterocarpus macrocarpus and Pterocarpus santalinus，and 2 adulterants of sandalwood such as Gluta sp.and Pterocarpus tinctorius.After ultrasonic treatment in MeOD，the extracts were determined by 1H NMR.Results showed that the contribution of first three principal components derived from the PLS-DA model was added up to 79%.Except that group Dalbergia cochinchinensis interacted with group Dalbergia oliveri and group Pterocarpus santalinus，respectively，the other groups could be separated from each other.Obviously，the adulterants could be easily distinguished from the sandalwoods by this method.Therefore，the method was rapid and high sensitive in the distinguishment of adulterants，and showed a great potential in the identification of different species of sandalwood.关键词：sandalwood;nuclear magnetic resonance（NMR）;pattern recognition;partial least squares-discriminant analysis（PLS-DA）
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发布时间：2023-04-18 - 摘要：An analytical method of gas chromatography-triple quadrupole mass spectrometry with accelerated solvent extraction(ASE) was established for the determination of 8 kinds of super trace high chlorinated flame retardants dechloranes in surface soil,including mirex,syn declorane,anti declorane,declorane 602,declorane 603,declorane 604,anti Cl10DP and anti Cl11DP.Soil samples were extracted by ASE with hexane-acetone(1∶1,by volume) mixed solvent at 120 ℃,then on line purified with graphitized carbon black and followed by GCB/PSA solid phase extraction column clean up.The extract was analyzed by GC-MS/MS in MRM mode.The spike recoveries of the method for 8 target compounds in soil at low,medium and high levels ranged from 938% to 107%,847% to 101% and 990% to 108% with the relative standard deviations of 51%-13%,52%-83% and 43%-66%,respectively.The detection limits were in the range of 017-110 pg/g.This method was applied in the analysis on the surface soil samples from some urban and rural areas along the Beijing-Hangzhou Grande Canale.Results showed that the detection rates for 4 compounds ie.syn declorane,anti declorane,declorane 602 and mirex were higher than the others,in which the highest rate reached up to 350%,and the highest concentrations of syn declorane,anti declorane in Huaian were 650 ng/g and 244 ng/g,respectively.关键词：accelerated solvent extraction(ASE);gas chromatography-triple quadrupole mass spectrometry(GC-MS/MS);soil;dechlorane
- 960
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发布时间：2023-04-18 - 摘要：A gas chromatography-tandem mass spectrometric(GC-MS/MS) method was developed for the determination of 10 kinds of benzotriazole ultraviolet absorbents in coatings.Samples were air-dried into a film,then extracted with hexane or acetonitrile through ultrasonic method.The target ingredients were separated on a DB-5 column(30 m×0.32 mm×0.25 μm) and analyzed under MRM mode.The linear ranges for 10 kinds of benzotriazole ultraviolet absorbents were between 0.1 μg/mL and 10 μg/mL.The limits of detection of this method were 0.6 mg/kg,and the limits of quantitation were 2.0 mg/kg.The recoveries ranged from 71.6% to 112% with relative standard deviations(RSDs,n=6) not more than 5.5%.This method was rapid,convenient,accurate and reliable,and it was appropriate for the routine determination of benzotriazole ultraviolet absorbents in coatings.关键词：ultraviolet absorbents;benzotriazole;gas chromatography-tandem mass spectrometry(GC-MS/MS);determination
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发布时间：2023-04-18 - 摘要：Lipid was automatically coupled to DNA chains with i motif structure marked Cy3 and Cy5 at both ends by DNA synthesizer to form a DNA-lipid probe. The probe could be directly inserted into the surface of cell membrane by strong hydrophobic interaction between lipid and cell membranes, and realized the ratio detection of extracellular pH value under hypoxic and normoxic conditions. Under the condition of high pH, the fluorescent groups at both ends of the DNA strand with i-motif structure were separated without any FRET effect, while in the condition of low pH, the DNA strand with i-motif structure formed tetramer structure on the cell surface, and the fluorescent groups at both ends were close to each other, resulting in strong FRET effect.Quantitative detection of pH could be achieved by measuring the fluorescence intensity ratio of the two fluorophores.Accurate detection on extracellular pH in hypoxic environment using this probe is of great significance in physiology and pathology.关键词：hypoxic condition;extracellular pH;i-motif structure;lipid;fluorescence resonance energy transfer;imaging analysis
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发布时间：2023-04-18 - 摘要：A method was established for the identification of volatile compounds in recycled and virgin expanded polystyrene（EPS） containers by gas chromatography-mass spectrometry（GC-MS） combined with chemomtrics.The sample was firstly dissolved with dichloromethane,then added methanol to precipitate macromolecular polymer,finally analyzed by GC-MS.Multivariate statistical analysis,including principal component analysis（PCA） and orthogonal partial least squares discriminant analysis（OPLS-DA）,were used to discriminate both virgin and recycled containers,and screen the differential compounds responsible for the discrimination.Results showed that the main constituents in recycled and virgin EPS containers,included polymerization residues（styrene monomer,dimers and trimers）,benzene derivatives and some additives.41 compounds which are significantly different in the two kinds of containers were screened out based on OPLS-DA and t-test,and the discrimination method was improved.This method could be applied in the efficient discrimination of recycled and virgin expanded polystyrene（EPS） containers.关键词：recycled food containers;discrimination;gas chromatography-mass spectrometry（GC-MS）;principal component analysis（PCA）;orthogonal partial least squares discriminant analysis（OPLS-DA）;differential substance
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发布时间：2023-04-18 - 摘要：A high sensitive electrochemiluminescence（ECL） sensor was established for the determination of chloramphenicol（CAP） in water based on magnetic molecularly imprinted technique and strong inhibitation of CAP on ECL signal of Ru（bpy）2+3/tripropyl amine system.Chloramphenicol molecularly imprinted membranes（MIPs） were synthesized on the surface of Fe3O4-Au magnetic nanoparticles by self assembly，using Fe3O4-Au magnetic nanoparticles as carriers，4 aminothiophenol（4-ATP）and 2-acrylamido-2-methylpropane sulfonic acid（AMPs） as binary functional monomers，ethylene dimethacrylate（EGDMA） as a cross linking agent and ammonium persulphate（APS） as an initiator.The magnetic glassy carbon electrode（MGCE） modified with the magnetic molecularly imprinted polymer was used as an ECL sensor for CAP.Under the optimal conditions，there was a good linear relationship for CAP with ECL quenching values of the system in the concentration range of 0.010-100 ng/L，with a correlation coefficient（r） of 0.998 0 and a detection limit of 0.010 ng/L.Results showed that the sensor has a good application prospect in the determination of CAP with advantages of high sensitivity，good selectivity and wide linear range.关键词：electrochemiluminescense（ECL）;chloramphenicol（CAP）;molecular imprinting;bipyridine ruthenium
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发布时间：2023-04-18 - 摘要：A method was established for the determination of 4 fluoroquinolones,ie.ciprofloxacin(CIP）,enrofloxacin(EN）,ofloxacin（OF） and norfloxacin(NOR) in aquatic products by capillary electrophoresis-electrochemical luminescence（CE-ECL） with modified gold nanoparticle enrichment.The conditions for enrichment and CE separation were studied,and the conditions for ECL detection were also investigated based on the principle of enhanced Ru（bpy）2+3 electrochemiluminescence.Under the optimal conditions,there were good linearities for the 4 analytes enriched with modified gold nanoparticles in the concentration range of 0.05-10.0 μmol/L.The detection limits（S/N=3） were low to 0.02 μmol/L and the enrichment times were 104-127.This method was used in the analysis of 4 analytes in actual eels samples with recoveries of 94.5%-112% and relative standard deviations（RSDs） not more than 6.3%.关键词：modified gold nanoparticles;enrichment;fluoroquinolones drug;capillary electrophoresis-electrochemical luminescence（CE-ECL）
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发布时间：2023-04-18 - 摘要：A method was developed for the rapid determination of 32 pesticide residues,including organ ochlorine,organophosphate and pyrethroid pesticides,in milk based on gas chromatography-ion trap tandem mass spectrometry.Electron impact ionization or chemical ionization were selected for the analytes with different sensitivities.Experimental parameters influencing the behaviours of compounds in the analysis of MS/MS were investigated and optimized.The mechanisms for the influencing factors were also discussed.Under the optimal conditions,the calibration curves for 32 pesticides were linear in the ranges of 25（10）-500（200） μg/L with correlation coefficients more than 0994.The method detection limits（MDL） for fention and chlorpyriphos were 1.7 μg/kg and 2.8 μg/kg,respectively,while those for the other pesticides were in the range of 0.026-1.2 μg/kg.The recoveries for 32 pesticides at two spiked levels of 50 and 200 μg/kg（organochlorine pesticides were spiked at 20 and 100 μg/kg） ranged from 71.5% to 116% with relative standard deviations（RSDs） of 1.9%-14%.The proposed method was applied in the detection for real samples,and could reduce the possibility of false positive results with strong anti interference.关键词：gas chromatography-ion trap tandem mass spectrometry（GC-IT-MS/MS）;electron impact ionization;chemical ionization;organochlorine;organophosphate;pyrethroid
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发布时间：2023-04-18 - 摘要：To evaluate the migration of treemoss flavoring compounds in slim cigarettes from cut tobaaco to tobacco smoke,a gas chromatography–mass spectrometry(GC-MS) in selected ion monitoring mode was developed for the determination of orcinol monomethyl,orcinol,methyl atratate,ethyl hexadecanoate and ethyl orsellinate in cut tobacco and tobacco smoke.The influences of solvent,extraction time and matrix effect were investigated.The tobacco sample was extracted with ethyl acetate,and quantified externally with matrix matched standard solution.Under the optimized conditions,there were good linear relationships for 5 selected analytes in the range of 0.02-2.0 mg/L with their correlation coefficients(r2) larger than 0.996For cut tobacco,the limits of detection(LODs) and limits of quantitation(LOQs) were in the ranges of 0.79-30 ng/mL and 2.6-10.0 ng/mL,respectively,with spiked recoveries of 90.5%-103% and relative standard deviations(RSDs,n=6) of 2.3%-12%.For tobacco smoke,LODs and LOQs were in the ranges of 0.60-2.9 ng/mL and 2.0-9.6 ng/mL,respectively,with average spiked recoveries of 856%-104% and RSDs(n=6) of 1.6%-9.3%.The proposed method was applied in the determination of 5 analytes in cut tobacco and tobacco smoke followed by the evaluation of the migration of treemoss components from cut tobacco to tobacco smoke.The results showed that the method was handy,sensitive and reliable,and could satisfy the requirements for the determination of the 5 analytes both in cut tobacco and tobacco smoke.关键词：slim cigarette;treemoss;gas chromatography–mass spectrometry(GC-MS);matrix effect;migration ratio
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发布时间：2023-04-18 - 摘要：A method of ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) combined with internal standard method was developed for the simultaneous determination of 19 kinds of fluoroquinolones antibiotic(FQs) residues in soil based on QuEChERS(Quick,Easy,Cheap,Effective,Rugged,Safe) pre-treatment.Firstly,5.0 g of soil was blended with 100 μL 10 mg/L internal standard compounds,then the analyte was extracted with 20 mL 0.1 mol/L EDTA-McIlvaine buffer and acetonitrile(1∶1,by volume),cleaned-up with a matrix dispersive solid phase extraction material(150 mg anhydrous MgSO4,15 mg PSA,15 mg C18),finally detected by UPLC-MS/MS with electrospray ionization in positive ion scanning under multiple reaction monitoring mode.Under the optimized conditions,the limits of detection and quantitation of the method were in the ranges of 0.2-1.0 μg/kg and 1.0-5.0 μg/kg,respectively,with correlation coefficients(r2) of 0.992-0998. Recoveries for 19 FQs at three spiked levels of 10,50 and 200 μg/kg ranged from 65.2% to 104% with relative standard deviations(n=5) not more than 14%.The method was simple,rapid and accurate,and was suitable for the determination of fluoroquinolones antibiotic residues in soil.关键词：QuEChERS;ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS);soil;fluoroquinolone antibiotics(FQs);isotope labelled internal standards;matrix dispersive solid phase extraction
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发布时间：2023-04-18 - 摘要：An analytical method was established for the determination of thiacloprid,spirotetramat and its four metabolites residues in litchi and longan by high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS) with QuEChERS cleanup.The residues in samples were extracted with acetonitrile,dehydrated with anhydrous magnesium sulfate and sodium chloride,then purified with C18 and GCB.The extract was separated on a Poroshell-120 EC-C18 column with 0.1% formic acid-acetonitrile as mobile phase by isocratic elution,detected by HPLC-MS/MS with positive electrospray ion source in multi reaction monitoring(MRM) mode,and quantified by external standard method.Results showed that there existed good linearities for six analytes in the range of 1-500 μg/L with their correlation coefficients(r2) more than 0.990.The limits of detection(LODs) and limits of quantitation(LOQs) were 0.03-0.3 μg/kg and 0.1-1.5 μg/kg,respectively.The average recoveries for the analytes at spiked levels of 1,10,100 μg/kg were in the range of 80.4%-99.5% with relative standard deviations of 1.4%-6.4%.The developed method was simple,sensitive,accurate and reliable,and could meet the requirements for rapid screening and monitoring of thiacloprid，spirotetramat and its metabolites in fruits such as litchi and longan.关键词：high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS);QuEChERS;thiacloprid;spirotetramat and its metabolites;litchi;longan
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发布时间：2023-04-18 - 摘要：A method for the simultaneous determination of 24 water soluble synthetic colors in premade cocktails was developed using ultra performance liquid chromatography with diode array detector(UPLC-DAD).In this paper,the chromatographic conditions for mobile phase,column and eluting gradient were optimized,and the best separation conditions were as follows:column:a Waters BEH C18 column(2.1 mm×50 mm,1.7 μm),mobile phase:10 mmol/L ammonium acetate solution (pH 625) and methanol-acetonitrile(2∶8,by volume),eluting by a gradient program.Under the optimized conditions,all the water soluble synthetic colors could be rapidly separated within 16 min.There were good linear relationships for the analytes in the concentration range of 0.01-50.0 mg/L with their correlation coefficients(r2) greater than 0.998 0.The limits of detection(LOD,S/N=3) and the limits of quantitation were in the ranges of 0.66-27.78 μg/L and 2.19-92.59 μg/L,respectively.The intra day and inter day RSD for the analytes were in the ranges of 0.04%-5.3% and 0.08%-6.4%,respectively.The recoveries for the synthetic colors ranged from 53.4% to 114%.With the advantages of many kinds of dyes detected,short analysis time and low detection limit,the method was successfully applied in the determination of cocktail samples on the market.关键词：synthetic colors;premade cocktails;ultra performance liquid chromatography with diode array detector(UPLC-DAD)
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发布时间：2023-04-18 - 摘要：In this study，a liquid cathode glow discharge-atomic emission spectrometry（LCGD-AES）was developed for the simultaneous determination of K，Ca，Na and Mg in salt mine of Geermu，in which needle like Pt was served as anode and overflowing electrolyte from a quartz capillary acted as the liquid cathode.The effects of discharge voltage，solution flow rate，supporting electrolyte，solution pH and interfering matrix components on the emission intensity were investigated in detail.The results were compared with those by ion chromatography（IC）.The optimum conditions were as follows:discharge voltage:650 V，flow rate:3 mL·min-1 and supporting electrolyte:pH 1.0 HNO3.The detection limits（LODs）for K，Ca，Na and Mg were 0.100 0，0.048 0，0.002 4 and 0.003 9 mg·L-1，respectively.The relative standard deviations（RSDs）were 0.57%，1.8%，0.94% and 1.8%，respectively.The results obtained by LCGD-AES were consistent with those by IC，and the recoveries for the analytes were in the range of 95.4%-108%.关键词：liquid cathode glow discharge（LCGD）;atomic emission spectrometry（AES）;salt mine;metal elements;high sensitive detection
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发布时间：2023-04-18 - 摘要：A method was developed for the determination of acephate and methamidophos in soil by ultrahigh performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) with ultrasonic extraction.10.0 g soil sample was extracted with 200 mL methanol under ultrasonic assistance for 30 min.Then the clear supernatant extract was filtered through 0.22 μm membrane,and analyzed by UPLC-MS/MS with external standard method.There were good linear relationships for acephate and methamidophos both in the range of 0.002-20.0 μg/L with their correlation coefficients(r2) larger than 0.999.The detection limits for acephate and methamidophos in soil were 0.004 9 μg/kg and 0.003 4 μg/kg,respectively.The recoveries for acephate and methamidophos at three spiked levels of 0.400,4.00 and 40.00 μg/kg were in the ranges of 83.0%-91.5% and 88.0%-94.8% with their relative standard deviations(RSDs,n=6) of 2.3%-4.8% and 1.8%-4.2%,respectively.The method was simple,rapid,sensitive and accurate in both quantitation and qualitation,and was suitable for the routine determination of acephate and methamidophos in soil samples.关键词：acephate;methamidophos;ultrasonic extraction;UPLC-MS/MS
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发布时间：2023-04-18 - 摘要：An ultra performance liquid chromatography-tandem mass spectrometric(UPLC-MS/MS) method was developed for the determination of 3 kinds of brevetoxins(BTX) in shellfish.The samples were extracted with acetone,and purified on a C18 solid phase extraction column.The separation of the analytes was performed on an ACQUITYTM UPLC BEH C18 column with 5 mmol/L ammoumium acetate containing 0.1% formic acid-acetonitrile as mobile phase,and detected in multiple reaction monitoring(MRM) mode.The external standard method was used for quantitation.Results showed that there were good linear relationships for BTXs in the range of 1.0-100 μg/L with correlation coefficients(r2) not less than 0.996.The quantitation limits of the method were 3.0 μg/kg.The recoveries for the brevetoxins ranged from 80.0% to 87.5% with relative standard deviations of 1.3%-5.4%.The method was suitable for the determination of brevetoxins in shellfish with advantages of simple processing,high sensitivity and good stability.关键词：solid phase extraction;ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS);shellfish;brevetoxin
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发布时间：2023-04-18 - 摘要：A simple and sensitive method was established for the detection of histamine by using the current-time curve based on a colloidal gold modified glass carbon electrode(AuCS/GCE).The electrochemical properties of the modified electrode were investigated.The pH value of the base solution,and the electrochemical detection methods and conditions for histamine were optimized.Results showed that there was a good linear relationship for the response current(-I,μA) of histamine on the AuCS/GCE in the concentration(c,μmol/L) range of 0.1-64 μmol/L,with the detection limit of 0.033 μmol/L.The recoveries for histamine in the hairtail and yellow croaker samples were in the ranges of 94.4%-106% and 91.8%-106%,respectively.The method was simple,rapid and low cost,and was suitable for the determination of histamine in food samples such as hairtail and yellow croaker.关键词：histamine;colloidal gold;current-time curve method;fish samples
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发布时间：2023-04-18 - 摘要：A method of laser Raman spectrometry was developed for the detection of DNA bases.The Raman spectra of adenine(A),guanine(G),cytosine(C) and thymine(T) were collected with laser Raman spectrometer in this work.The characteristic peaks in the spectra for each DNA base were analyzed,which were used to determine the components of DNA base mixtures.Results demonstrated that the characteristic peaks mainly ranged from 175 cm-1 to 1 800 cm-1.The peaks of A and G were higher than those of C and T when the integration time and laser power were certain.The strongest Raman signals for A,G,C,and T are at 723,648,791 and 1 368 cm-1,respectively.Each DNA base could be determined by using the characteristic peaks from the mixed DNA bases within 2 min.关键词：laser Raman spectrometry;DNA base;characteristic peak
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发布时间：2023-04-18 - 摘要：Sample pretreatment is a key part in the process of sample analysis.Some additional fields such as microwave，light，pressure and ultrasound，which are able to speed up mass transfer of solute or accelerate sample separation process，have been widely adopted in sample pretreatment.Electric field assisted sample treatment techniques have turn out to be a research hotspot in sample pretreatment due to its excellent extraction efficiency and selectivity in micro trace analysis.Moreover，these techniques have been successfully applied in food analysis，environment analysis and bio analysis.The progress of electrical field assisted extractions，including the electrical field assisted membrane extraction，solid phase micro extraction，liquid phase micro extraction is introduced in this review.Furthermore，the development trend of electric field assisted sample preparation techniques is prospected.关键词：electrical field assisted;extraction;sample preparation;review
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发布时间：2023-04-18 - 摘要：The toxicological effects of chiral pesticide enantiomers on organisms,as well as residues and metabolic transformation in organisms are different due to the differences in the properties of enantiomers.Agricultural products as an important source of food are closely related to human health,so it is very important to distinguish the enantiomer residues of chiral pesticides in agricultural products.By retrieving the literature articles published in recent years on the analysis of chiral pesticide residues in agricultural products,the applicationes of different chromatographic techniques such as gas chromatography,capillary electrophoresis,liquid chromatography and convergent chromatography are summarized,analyzed and prospected in this paper.It provides a reference for the further research on enantiomers of chiral pesticides in agricultural products.关键词：chromatographic method;chiral pesticides;enantiomers;residues analysis;agrocultural products
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发布时间：2023-04-18
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