最新刊期
卷 38 ， 期 7 ， 2019
- 摘要：A method was established for the determination of 508 pesticide reisdues in Panax notoginseng by liquid chromatography-tandem mass spectrometry(LC-MS/MS).The samples were extracted by modified QuEChERS method,followed by the clean up of d SPE extraction.The extract was determined by LC-MS/MS in multi reaction monitoring(MRM) mode,and quantified by the internal standard method.There were linear relationships for the 508 pesticides in the range of 0005-04 mg/L with limits of detection(LOD) of 0005-01 mg/kg.Except for 8 pesticides,the recoveries for other 500 pesticides at spiked level of 100 μg/kg were in the range of 502%-117%with relative standard deviations(RSD) not more than 15%,in which,the recoveries for 468 pesticides were in the range of 70%-120%.With the advantages of simplicity,rapidness,good sensitivity and accuracy,the method could meet the requirements for multiple pesticide residues analysis,and is suitable for the determination of 508 pesticide residues in Panax notoginseng.关键词：Panax notoginseng;pesticide residue;QuEChERS;liquid chromatography-tandem mass spectrometry(LC-MS/MS)
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发布时间： - 摘要：The porous material O pinacolyl methylphosphonic acid imprinted polymer microspheres were synthesized through designing pre assembly system,based on the interaction between the degradation product of Soman(O pinacolyl methylphosphonic acid) molecules with methylacrylic acid and acrylamide functional monomer molecules discussed by techniques such as 31P ｛1H｝NMR spectroscopy and 1H NMR spectroscopy.Scatchard analysis showed that the maximum apparent binding amount Qmax was 661 μg/g（AM as monomer）,and a straight line was presented in the diagram of a low adsorption range(Q＜500 μg/g).In static adsorption experiment,the polymer was observed to be regularly selective to homologous five alkyl phosphonates monoalkyl esters,and the identification factors α to other compounds with different structures were decreased obviously.A solid phase extraction column using this synthesized polymer microsheres was used in the separation of trace O pinacolyl methylphosphonic acid containing a large number of interferents with a remarkable effect.Results showed that the polymer synthesized provided an effective means for analysis and identification of trace degradation products of related chemical warfare agents in the complex samples.关键词：chemical warfare agents;O pinacolyl methylphosphonic acid;molecule imprinted polymer;trace analysis;solid phase extraction
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发布时间： - 摘要：A bio probe was firstly prepared by assembling sulfhydryl DNA on the surface of Au nanoparticles(AuNPs).Then the 3′-OH end on the probe DNA was extended under the catalysis of terminal deoxynucleotidyl transferase(TdTase),and produced a long single chain DNA(single stranded DNA,ssDNA).The probe and the long ssDNA were characterized by agarose gel electrophoresis and atomic force microscopy(AFM).Results showed that,under the action of TdTase,DNA containing 3′-OH achieved an efficient extension at the nano interface,and the chain length was up to 850 nm though it was in the irregular coiled state.Afterwards,this DNA growth strategy combined with aptamer technology was applied to construct an aptasensor for the detection of enrofloxacin(ENR).The aptamer fragment 1 was firstly assembled on the surface of the AuNPs,then the aptamer fragment 2 was assembled on the surface of the magnetic particle activated by glutaraldehyde.After experiencing the TdT-mediated DNA growth strategy,the aptasensor had a good response to ENR concentration in the range of 10-10×105 ng/mL with a detection limit of 10 ng/mL.At the same time,the detection signal for enrofloxacin was significantly different from those for ciprofloxacin,ofloxacin,norfloxacin and other control groups.The results showed that the TdTase based aptasensor could provide a new research idea or method for food safety detection and other fields with the advantages of convenient operation,good sensitivity and excellent specificity.关键词：nano bioprobe;terminal deoxynucleotidyl transferase(TdTase);DNA growth;aptasensor;enrofloxacin
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发布时间： - 摘要：In this study,water soluble copper doped carbon nanodots(Cu-CDs) with high fluorescence quantum yield were prepared by one step hydrothermal method using citric acid and ethylenediamine as precursors and copper sulfate as metal dopants.A new method for the fluorescence determination of anthrax biomarker based on copper doped carbon nanodots was established based on the strong chelation of 2,6 pyridinedicarboxylic acid(DPA) with carbon nanodots.Under the optimum experimental conditions,there were good linear relationships for the fluorescence quenching rate of Cu-CDs with DPA in the concentration ranges of 5-100 nmol/L(r2=0994 1) and 150-400 nmol/L(r2=0997 6),and the detection limit of the proposed method was 23 nmol/L.With the advantages of low cost,high specificity,high sensitivity and simple operation,the method has a good application prospect in detection of anthrax biomarker.关键词：copper doped carbon nanodots;fluorescent probes;anthrax biomarker;2,6 pyridinedicarboxylic acid
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发布时间： - 摘要：A novel method was established for the rapid detection of ephedrine in urine by portable high resolution ion mobility spectrometry with poly vinylidene fluoride microporous membrane-polydopamine-graphene oxide solid phase extraction.The new type of solid phase extraction membrane could realize a 5 min of rapid adsorption,a 10 min of elution and a 30 ms of injection detection for ephedrine by optimizing preparation process,adsorption and elution process.The results showed that good linearity was found from 0124 μg/mL to 6129 μg/mL for ephedrine with a detection limit of 960 ng/mL,and the recoveries ranged from 910% to 113%.The method could be applied in the rapid detection of ephedrine in urine,and provide an effective means for on line detection and on site monitoring of driving under the inference of drugs.关键词：poly vinylidene fluoride;graphene oxide;solid phase extraction;portable high resolution ion mobility spectrometry;ephedrine;urine sample;driving under the inference of drugs
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发布时间： - 摘要：A capillary electrophoresis with monolithic column solid phase extraction was established for the separation and detection of polyphenols such as rutin,chlorogenic acid and quercetin in mulberry leaves.The polybutyl methacrylate-ethylene glycol dimethacrylate(poly(BMA-co-EDMA)) monolithic column was synthesized by using butyl methacrylate(BMA) as monomer and ethylene glycol dimethacrylate(EDMA) as crosslinker.Effects of solid phase extraction conditions such as leacheate type,flow rate and volume of leacheate,eluent type on extraction efficiency were investigated,and the separation and analysis of three polyphenols were performed by capillary electrophoresis.Under the optimized conditions,there were good linear relationships for rutin,chlorogenic acid and quercetin in the range of 10-160 μg/mL with correlation coefficients of 0995 5,0998 5 and 0999 5,respectively.The detection limits for rutin,chlorogenic acid and quercetin were 465,112,349 μg/mL,respectively.The average recoveries for three analytes were 947%,989%and 102%,with relative standard deviations of 24%,098%and 28%,respectively.Results showed that the solid phase extraction column could be used for the effective enrichment and purification of three polyphenols in mulberry leaves.The method is simple,rapid and sensitive,and is suitable for the separation and analysis of three polyphenols in mulberry leaves.关键词：monolithic column;solid phase extraction;mulberry leaf polyphenols
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发布时间： - 摘要：An acephate mesoporous molecularly imprinted polymer(MIP) was prepared by sol-gel technique using acephate as template molecule,3 aminopropyl propyl triethoxysilane(APTES) as functional monomer,surfactant dodecylamine(DDA) as mesoporous template and tetraethoxysilane as coupling agent.And it was characterized.Results of Scatchard analysis showed that there existed two kinds of binding sites.The values of apparent maximum absorption capacity were calculated as follows:Qmax1=4703 mg/g and Qmax2=9031 mg/g,and the dissociation constants:kd1=5714 mg/L and kd2=18868 mg/L.The adsorptive dynamics results showed that the adsorption of the polymer toward acephate accorded with quasi secondary dynamics model.The results of adsorption thermodynamics showed that the adsorption process was exothermic.The prepared polymer was used for matrix solid phase dispersion(MSPD) extraction of acephate in grains.The optimum experimental conditions were as follows:the ratio of polymer to sample:1∶1,grinding time:8 minutes,the washing solvent:ethanol-water(2∶1,by volume),the eluent:acetonitrile-acetic acid(19∶1,by volume).The final eluent was detected by high performance liquid chromatography,and the calibration curve of acephate was linear in the range of 003-03 μg/g with a detection limit of 0015 μg/g.Recoveries for acephate were between 925%and 971%with relative standard deviations(RSD) of 29%-37%.With the advantages of high selectivity of mesoporous molecularly imprinting technique and the rapid separation of matrix solid phase dispersion extraction,this method provides a new idea for the residue analysis of acephate.关键词：acephate;mesoporous molecularly imprinted polymer;grains;matrix solid phase dispersion extraction;high performance liquid chromatography
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发布时间： - 摘要：An ultra high performance liquid chromatography coupled with linear ion trap-orbitrap mass spectrometric(UPLC-LTQ-Orbitrap-MS) method was developed for the qualitative analysis of main chemical constituents in Duzhong granules,a Chinese medicine.The sample was ultrasonically extracted with methanol,then separated on a Thermo Scientific Syncronis C18 chromatographic column(100 mm×21 mm,19 μm) by gradient elution with acetonitrile-01% formic acid as mobile phase.The data were collected by using LTQ-Orbitrap-MS in negative ion mode.According to the contrast of the reference standards and the accurate masses of molecules,a total of 25 compounds in Duzhong granules were identified,including 8 iridoids,8 flavonoids,5 phenylpropanoids,3 lignans and 1 non reducing disaccharide.Results showed that,with the advantages of simplicity,rapidness and accuracy,the developed method was suitable for the identification of chemical constituents in Duzhong granules,which provided a reference for the pharmacological basis of further analysis of Duzhong granules.关键词：Duzhong granules;ultra high performance liquid chromatography coupled with linear ion trap-orbitrap mass spectrometry(UPLC-LTQ-Orbitrap-MS);qualitative analysis;flavonoids;iridoids
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发布时间： - 摘要：In this study,the typical mangrove wetland soils from the Nanhaidi of Zhanjiang Bay were investigated to discuss the special habitat characteristics of mangrove wetland soil.The minerals in the soils were identified by Fourier transform infrared(FTIR) and X ray diffraction(XRD),and the morphological characteristics of soil particles were observed by scanning electron microscopy(SEM) to obtain the chemical components.The soil samples from nearby mudflats were also collected for comparative study.Results showed that the mineral components in mangrove wetlands soils were mainly composed of kaolinite,quartz,muscovite,halloysite,diamond and serpentine,more diverse than those in mudflats soils which simply contained quartz and kaolinite.The morphologies of soil particles in mangrove wetland emerged in schistose aggregates,and the main elements were C,O,S,Al,Si,Mg and Fe,etc.Heavy metal elements such as Cu,Zn,Mo were commonly found in the soil particles of mangrove wetland.The mangrove wetland soil was also abundant in sulfide.However,the above characteristics were not found in the mudflats soil,which indicated that the mangrove wetland was in a special ecological environment,and its soil sediment was rich in organic matter,Fe and S,etc.Thus,it was more favorable for the enrichment of sulfides or heavy metals than mudflats.关键词：mangrove wetland;soil minerals;X ray diffraction(XRD);fourier transform infrared(FTIR);scanning electron microscope(SEM)
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发布时间： - 摘要：A novel high performance liquid chromatography-inductively coupled plasma mass spectrometry(HPLC-ICP-MS) was established for the determination of five bromine contained preservatives,ie.benzalkonium bromide,2 bromo 2 nitro 1,3 propanediol,5 bromo 5 nitro 1,3 dioxane,methyldibromo glutaronitrile and bromochlorophene in cosmetics.The samples were ultrasonically pretreated with methanol containing 01%formic acid.The analytes containing 79Br were separated on an Agilent Eclipse-C18 column(150 mm×46 mm,5 μm) using 01%formic acid-methanol as mobile phases by gradient elution,and then analyzed by ICP-MS with external standard method.There were good linear relationships for five analytes in the range of 05-100 mg/L with correlation coefficients(r) larger than 0999.The detection limits for five bromine contained preservatives were in range of 15-30 μg/g.Recoveries for the analytes in different spiked cosmetics matrixes ranged from 912%to 108%with relative standard deviations(n=6) of 13%-42%.The method was fast,accurate,sensitive and selective,and was suitable for the simultaneous determination of five bromine contained preservatives in cosmetics.关键词：high performance liquid chromatography;inductively coupled plasma mass spectrometry;bromine contained preservatives;cosmetics
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发布时间： - 摘要：A simple and efficient method for the detection of quercetin was established based on the fluorescence quenching effect of quercetin toward organosilane functionalized carbon dots(SiCDs).The highly luminescent SiCDs were prepared through one step hydrothermal method,with citric acid as carbon source and organosilane as surface coating agent.The as synthesized SiCDs showed a strong emission at 450 nm when excited at 360 nm,and the fluorescence quantum yield was up to 692%.Effects of action time,pH value and carbon dots concentration on the detection of quercetin were investigated.Furthermore,the fluorescence quenching mechanism was elucidated.Under the optimal conditions,a linear fluorescence signal response to quercetin concentration was obtained in the range of 10-400 μmol/L with a correlation coefficient(r) of 0996 7,and the detection limit was 38 nmol/L.The method was applied in the detection of quercetin in practical samples with satisfactory results.关键词：organosilane functionalized carbon dots(SiCDs);fluorescence quenching;nanoprobe;quercetin
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发布时间： - 摘要：A sensor for colorimetric determination of silver and mercury ions based on G quadruplex-hemin DNAzymes was fabricated.The G quadruplex-hemin DNAzymes was formed by the combination of G quadruplex(5′ CTGGGAGGGAGGGAGGGA 3′) with hemin,which could catalyze H2O2 to oxide the substrate efficiently,and make the colorless solution become green.The presence of Ag+ or Hg2+ in the solution would hinder the formation of the DNAzyme,and the solution color became lighter.Under the optimal experimental conditions,there were good linear relationships for the absorbance of the solution with Ag+ and Hg2+ in the concentration ranges of 1000-1 0000 nmol/L and 800- 8000 nmol/L,with detection limits(3δ/Slope) of 559 nmol/L and 643 nmol/L,respectively.This method was of good selectivity,and was applied in the detection of real samples with satisfactory results.关键词：G quadruplex-hemin DNAzymes;colorimetric determination;silver ion;mercury ion;sensor
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发布时间： - 摘要：Specific chromatogram of ginger essential oil was studied by ultra performance convergence chromatographic(UPC2) method.The ginger essential oil was diluted with n heptane,and separated on UPC2 system with photo diode array(PDA) detector,using supercritical CO2 as mobile phase and acetonitrile as cosolvent at a flow rate of 08 mL/min by gradient elution.A spectral library for characteristic peaks and standard specific chromatogram of ginger essential oil from Anhui was established.By comparison with the characteristic peaks from PDA library and similarity evaluation,the resemblance of specific chromatogram was found higher than 09 among the ginger essential oil from Anhui and the standard control.The relative standard deviations(RSD) for relative retention time and relative peak area of common peaks were less than 30%.This method has good precision,reproducibility and stability,and could meet the requirements for the evaluation of specific chromatogram.Coupled with cluster analysis and principal component analysis,the UPC2 specific chromatogram method was successfully used to distinguish 20 samples from different habitats.This study provided a novel,convenient and rapid method for the quality control and origin traceability of ginger essential oil.关键词：ginger essential oil;ultra performance convergence chromatography（UPC2）;specific chromatogram
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发布时间： - 摘要：A smartphone method based on molecularly imprinted kit was developed for the determination of glucose in blood.The imprinted kit was composed of glucose molecularly imprinted paper and chromogenic agent.The glucose in blood was specifically combined with the obtained glucose imprinted paper,other impurities were eluted with chloroform.Then,chromogenic reagent was added into the surface of the test paper for coloration.UV-Vis spectra showed the imprinted paper adsorbed the glucose in blood with an adsorption time of 5 min and a maximum adsorption capacity of 0673 mg per piece.The generated color was detected by the combination of smartphone photographing with a free software GIMP 28.Results showed that there existed a good linear relationship between the chromaticity(H) and the negative logarithm of glucose concentration(pC),with a linear equation of H=421-233pC and a correlation coefficient(r) of 0993.The method was applied in the determination of glucose in rabbit blood with recoveries of 918%-108%.Compared with blood glucose meter,this method is cheaper and more convenient.关键词：smartphone detection;molecularly imprinted kit;glucose in blood
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发布时间： - 摘要：A novel flow injection-chemiluminescence(FI-CL) method was established for the determination of praziquantel based on the strong inhibition of praziquantel on Luminol-NaIO4 chemiluminescence system.Under the optimal experimental conditions,there was a good linear relationship between relative intensity of chemiluminescence and praziquantel in the concentration range of 40×10-8-10×10-6 mol/L,with a limit of detection(LOD) of 99×10-9 mol/L.The relative standard deviation(RSD,n=11) was 14% for the determination of 20×10-7 mol/L praziquantel.The proposed method was used for the detection of praziquantel in the spiked pig feed sample with recoveries of 985%-100%.The method was successfully applied in the determination of praziquantel in pig feed with satisfactory results.关键词：flow injection;chemiluminescence;Luminol-NaIO4;praziquantel;pig feed
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发布时间： - 摘要：A method was established for the determination of streptomycin(STR) and dihydrostreptomycin(DHS) in vegetable foods(apple,celery,capsicum and lentil) based on high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS).The sample was extracted with phosphate buffer and cleaned up with a WCX solid phase extraction cartridge.The extracts were separated on an Atlantis Hilic Silica column(100 mm×30 mm,3 μm) using acetonitrile-01 mol/L ammonium formate and 01% formic acid as mobile phases by isocratic elution,then detected by HPLC-MS/MS in positive ion mode under multiple reaction monitoring(MRM) mode.An external standard method was used for quantitative analysis.The calibration curves for streptomycin and dihydrostreptomycin showed good linearity in the range of 10-120 μg/L with their correlation coefficients(r) more than 0999.The limits of quantitation(LOQs) were both 125 μg/kg.The average recoveries for streptomycin and dihydrostreptomycin at three spiked levels of 125,250 and 500 μg/kg ranged from 836% to 101%,with the relative standard deviations(RSDs) of 23%-76%.With no need of ion pair reagents resulting in the contamination of liquid chromatography-mass spectrometer,the method is simple,rapid,reliable and stable,and could meet the requirements for determination of streptomycin and dihydrostreptomycin residues in most vegetative samples.关键词：vegetable foods;streptomycin;dihydrostreptomycin;HPLC-MS/MS
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发布时间： - 摘要：A γ aminobutyric acid bonded silica(Sil-GABA) stationary phase was prepared in a green medium with only water as solvent,which was characterized by Fourier transform infrared spectroscopy and elemental analysis.The separation mode and analytical performance of the Sil-GABA stationary phase were evaluated through a series of experiments when it was used as packing material for capillary column.Results showed that three nitrochlorobenzene positional isomers and seven sulfonamides were separated effectively on the Sil-GABA stationary phase with ammonium acetate as mobile phase in an aqueous liquid chromatography mode.Four benzoic acid compounds were separated with high concentrations of organic solvents as mobile phases in a hydrophilic chromatography mode.Additionally,three nitroaniline positional isomers were also separated in a reversed phase chromatography mode.Under the optimal conditions,the relative standard deviations(RSD) of the retention times for the sulfonamides were within 32%,indicating that the Sil-GABA column has a good reproducibility.The prepared Sil-GABA stationary phase could provide potential applications in capillary liquid chromatography with multiple retention mechanisms.关键词：γ aminobutyric acid bonded silica(Sil-GABA);green preparation;capillary liquid chromatography
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发布时间： - 摘要：Tip wear of atomic force microscope(AFM) is a crucial factor to influence AFM image quality.In order to investigate the tip wear of AFM,the ultra flat glass surface with a roughness(Rq) lower than 05 nm was selected as the scanning sample,which was used for the efficiency assessment of tip wear.Under the test conditions，such as low target amplitude ratio(10%) for probe cantilever,low set point amplitude ratio(10%),low scanning speed(10 Hz) and moderate I-gain(17),the tip wear of the probe was minimal,which could effectively extend the service life of the probe.Furthermore,the mechanism for tip fracture and wear in the test process was speculated by comparing the morphologies of the probe tip of scanning electron microscope(SEM) in different test situations.关键词：atomic force microscope(AFM);tip wear;roughness;tapping mode
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发布时间： - 摘要：Rapid and reliable detection methods for food borne pathogen are the key points for food safety control.However,traditional culture based procedure for bacterial identification,generally taking 5 to 7 days and requiring skilled person and non portable equipment,is incompetent for point of care or on site detection.Thus,several isothermal amplification methods characterized by rapidness and thermal cycle independent were developed to fulfill some specific needs for point of care or on site detection.In this review,mechanisms for isothermal amplification methods,designated as loop mediated isothermal amplification,rolling circle amplification,strand displacement amplification,nicking enzyme signal amplification,exonuclease Ⅲ assisted amplification,were explained and compared in detail.Besides,some drawbacks shared by these methods were highlighted,and ways to overcoming those drawbacks such as adoption of propidium monoazide,novol fluorescent dye,high throughput pretreatment equipment and microfluidic chip were provided based on the recent publications of the authors group and others.关键词：isothermal amplification;bacterial detection;point of care detection;on site detection;food safety
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发布时间： - 摘要：The phenomenon of protein aggregation during the production of a bio therapeutic drug is an increasing challenge to many pharmaceutical research and development groups and companies.Aggregation may cause a number of deleterious effects on protein drugs,including the loss of efficacy,the induction of immunogenicity,alteration of pharmacokinetics and reduction of shelf life.Size exclusion chromatography(SEC) is a traditional technique widely employed for the qualitative and quantitative evaluation on pharmaceutical proteins and their aggregates,which possesses some advantages such as easy operation,mild mobile phase conditions and nondestructive detection of the conformational structure and local environment,etc.However,SEC method still remains a number of limitations,in which the most important one is the adsorption of protein to resin.The theory for SEC separation is outlined in this review,and some methods how to reduce the nonspecific adsorption problem are described.Some techniques mutually comlementary with SEC are listed, which could be used in the analysis on pharmaceutical protein aggregates.Finally,the future development and outlook for SEC technique are described.关键词：size exclusion chromatography;protein drug;protein aggregation;nonspecific adsorption
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