最新刊期
卷 34 ， 期 5 ， 2015
- 摘要：A confirmatory method was developed to determine 5 alkaloids including morphine,codeine,thebaine,papaverine and noscapine by high performance liquid chromatography quadrupole-orbitrap high resolution mass spectrometry（HPLC-Q/Exactive） in foodstuffs,such as chafing dish materials,condiments,barbecue,and liangpi.The sample was extracted with hydrochloric acid solution in ultrasonic assisted condition,and chloroform was used for removing the fat.The purification was carried out with an ion exchange solid phase extraction（SPE） column,using the ammoniated methanol-ethyl acetate as eluent.The separation of analytes was performed on an Accucore aQ column.To finish the accurate screening poppy features ingredients in food,the molecular ion accurate mass was used by orbitrap full scan in electro-spray ionization,while product ions full scan were triggered by automatically setting the threshold.The quantification was implemented with the isotope internal standard.Meanwhile,the possible fragmentation patterns were studied.Under the optimized experimental conditions,the obtained mass accuracy errors of 5 analytes were less than 5 ppm.The limit of quantitation（LOQ） was 2.0 μg/kg for morphine,0.2 μg/kg for codeine,0.1 μg/kg for papaverine,thebaine and noscapine.Good linear relationships（r2> 0.999） were obtained between analyte concentrations and peak areas.The method recoveries were in the range of 63.4%-112.8%,and the relative standard deviation were 5.5%-13.6%.This method was used to analyze actual foodstuffs.The detected results showed that the quantification data was accurate and the confirmation data was reliable.关键词：quadrupole-orbitrap high-resolution mass spectrometry（Q-Exactive）;solid phase extraction;fragmentation;alkaloids;poppy
- 2064
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- 496
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发布时间：2023-05-18 - 摘要：A rapid method was developed for the simultaneous determination of 127 pesticide residues belonging to different chemical classes in cucumber,flowering cabbage,grape and banana by high performance liquid chromatography tandem mass spectrometry（HPLC-MS/MS）.The samples was prepared by the modified QuEChERS（quick,easy,cheap,effective,rugged and safe） method,extracted with acetonitrile containing 1% acetic acid,salted out with anhydrous magnesium sulphate and anhydrous sodium acetate,and cleaned up by adding primary secondary amine（PSA） and graphitized carbon black（GCB）.The 127 target compounds were separated on an Ultra AQ C18（100 mm×2.1 mm,3 μm） column using 5 mmol/L ammonium formate methanol solution and 5 mmol/L ammonium formate as mobile phase by gradient elution at a flow rate of 0.4 mL/min in 15 min,and analyzed by positive electrospray ionization tandem mass spectrometry under multiple reaction monitoring（MRM） mode.The external standard method was used for quantitative analysis.The calibration curves of 127 pesticide residues were linear in the range of 0.50-40.0 μg/L with correlation coefficients（r） more than 0.99．The recoveries at spiked levels of 10,20,50 μg/kg for all target compounds in the samples were in the range of 60.0%-118.5%,with relative standard deviations of 1.2%-21.9%.The limits of quantitation（LOQs，S/N≥10） were not more than 8.9 μg/kg.The method was simple,rapid,sensitive and reliable,and could be used in the screening and determination of 127 pesticide residues in fruits and vegetables.关键词：QuEChERS;high performance liquid chromatography tandem mass spectrometry（HPLC-MS/MS）;fruits and vegetables;pesticide residues
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发布时间：2023-05-18 - 摘要：A new compound 2-（2-hydroxy-3-methoxyl-phenyl）-5-（1-hydroxymethyl） C60 pyrrolidine derivative（FPD） was successfully synthesized with 1,3-dipolar cycloaddition reaction of C60 with o-vanillin and L-serine.Its structure was characterized by MS,FT-IR,UV-Vis,1H NMR and elemental analysis.FPD was immobilized on the surface of glassy carbon electrode（GCE） by drop coating method,and then Al3+was assembled on its surface.The probe DNA was fixed on the electrode surface by the electrostatic interaction between the negatively charged phosphate group of DNA and Al3+,and a new electrochemical DNA sensor was constructed successfully.The analytical performance of the biosensor was evaluated using methylene blue as the hybridization indicator.The results showed that a good linear relationship between peak currents signals of MB and logarithm value of the target compound concentrations（lgcS2） in the range of 1.0×10-15-1.0×10-9 mol/L was obtained,with a linear regression equation of Ip（10-6 A）=0.106 lg（cS2，mol/L）+0.735 and a limit of detection（S/N=3） of 5.4×10-16 mol/L.The selectivity experiments further showed that the complementary sequences and the base mismatch sequences could be well distinguished with this biosensor.关键词：C60 pyrrolidine derivative;DNA sensor;aluminum ion;methylene blue
- 1946
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- 443
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- 1
发布时间：2023-05-18 - 摘要：A comprehensive analytical method based on ultra performance liquid chromatography-quadrupole linear ion trap mass spectrometry（UPLC-QTRAP-MS/MS） was developed for the simultaneous determination of 10 nucleosides and nucleobases（uracil,cytidine,guanine,uridine,adenine,inosine,guanosine,thymidine,adenosine,2’deoxycytidine）in Polygoni Multiflori Radix.The sample was extracted with ultrapure water by ultrasonic machine at room temperature and centrifuged.Under the optimized conditions,good separations for 10 target compounds were obtained on a Waters Atlantis T3 column（2.1 mm×150 mm，3 μm）with a mobile phase of methanol-5 mmol/L ammonium acetate（0.1% acetic acid） at a flow rate of 0.4 mL/min.The target compounds were analyzed in the positive ion multiple reaction monitoring（MRM） mode.As a result,10 nucleosides and nucleobases obtained good linearities in the certain concentration ranges with correlation coefficients more than 0.99,and the limits of detection were in the range of 1.05-9.68 ng/mL.Average recoveries of 10 compounds were between 97.8% and 104.8%,and the relative standard deviations were between 1.8% and 5.0%.The method was simple,sensitive and accurate,and could provide a reliable and effective technique for the quality control of Polygoni Multiflori Radix.关键词：Polygoni Multiflori Radix;UPLC-QTRAP-MS/MS;origins;nucleosides;nucleobases;simultaneous determination
- 2030
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- 506
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发布时间：2023-05-18 - 摘要：A method to discriminate the quality grade of Minnan oolong tea Tieguanyin was developed based on comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry（GC×GC-TOF MS） coupled with cluster analysis and Fishers discriminate analysis.Samples of different qualities and production seasons from Anxi county were collected and extracted with acetone.The extracts were filtrated with activated carbon,and then analyzed by GC×GC-TOF MS.More than 1 000 peaks were obtained for each sample,which were used for the quality analysis.Among the compounds obtained,68 common compounds were detected from 24 different quality grades of Tieguanyin,and they were tentatively identified with comparison to the standard mass spectra in available databases,retention index and structured chromatogram for further analysis using IBM SPSS Statistics 19.Based on these common compounds,the scatter plot from cluster analysis based on Ward method presented a straightforward classified information for different grades of Tieguanyin tea.In addition,5 compounds which had significant impacts on the classification were selected using stepwise discriminate analysis,and these compounds were used as variables to establish 4 discriminated functions by Fisher’s discriminate analysis.The compliance for recognition of 24 tea samples was 95.8% obtained by Fisher’s discriminate analysis.The results demonstrated that the developed method could be used to discriminate the quality grade of Tieguanyin with reliability.关键词：two dimensional gas chromatography-time-of-flight mass spectrometry;Tieguanyin;acetone extracts;cluster analysis;Fishers discriminate analysis
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发布时间：2023-05-18 - 摘要：The molecular mechanism of inhibition on tyrosinase activity by luteolin was studied by enzyme kinetics experiment,fluorescence quenching experiment and molecular docking simulation.The enzyme inhibition kinetics experiment results showed that luteolin inhibited the activity of tyrosinase as a non-competitive inhibitor.The inhibition constants KI and IC50 were 86 mmol/L and 778.2 μmol/L,respectively.The fluorescence quenching experiment results showed that the interactions between luteolin and tyrosinase did not change the secondary structure of tyrosinase.As a static quenching,both hydrophobic interaction and hydrogen bonding stabilized the composite structure.Molecular docking simulation showed that the interaction between luteolin and amino acid residues in the hydrophobic pocket of tyrosinase existed.The interaction force mainly included hydrophobic interaction and hydrogen bonding.关键词：luteolin;tyrosinase;inhibitory effect;fluorescence quenching;molecular docking
- 1916
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- 436
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发布时间：2023-05-18 - 摘要：A fiber optic sensor for DNA detection based on fluorescence quenching was fabricated，using ［Ru（bipy）2DAFND］（ClO4）2 （Ru-DAFND，bipy=2，2′-bipyridine，DAFND=4，5-diazafluorene-9-p-nitrophenylhydrazone） embedded in sol-gel membrane as indicator for the optic sensing membrane.The membrane fixed on the sensor head was prepared by ethyl silicate hydrolysis using Ru-DAFND as fluorescence indicator，formamide as drying agent，and HCl as catalyst.The sensor was designed by using lock-in amplifier for signal measurement to detect ctDNA concentration.The results indicated that a linear relationship between relative phase delay （Δφ） of sensing membrane and DNA concentration was observed in the range of 2.6×10-8-5.4×10-6 mol/L in Tris buffer （pH 7.1），with a detection limit of 8.4×10-9 mol/L.The response time of senor was 70 s.The effects of solution pH value and foreign interferences to the performance of the sensor were investigated,and the results showed good stability and repeatability.关键词：polypyridyl Ru（Ⅱ） complex;fluorescence quenching;fiber optic DNA sensor;lock-in amplifier
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发布时间：2023-05-18 - 摘要：A method based on ultrasonic-assisted dispersive emulsion microextraction procedure coupled with high performance liquid chromatography(HPLC) was developed for the preconcentration and determination of Para red,Sudan Ⅰ,Sudan Ⅱ,Sudan Ⅲ and Sudan Ⅳ in chilli powder.Experimental conditions affecting the microextraction procedure such as types and volumes of extraction solvent,content of disperser solvent,salt concentration,pH value,extraction time and centrifugal time were optimized.The ultrasonic-assisted dispersive emulsion microextraction conditions were optimized by using 0.75 mL cyclohexane as extraction solvent and 10% acetonitrile as disperser solvent,and the mixture was oscillated for 1 min.The extractant phase was separated by centrifugation at 6 000 r/min for 5 min,then filtered through 0.22 μm nylon membranes and injected into the HPLC system for analysis.Under the optimum conditions,this method was employed to analyze five dyes in loose chilli powder and packaging chilli powder.At three spiked levels of 50-1 000 ng/g,the average recoveries for five dyes in chilli powder ranged from 82% to 114%,with relative standard deviations(RSD,n=3) between 0.7% and 8.8%.The calibration curves of 5 dyes were linear in the concentration range of 25-5 000 ng/mL with correlation coefficients(r2) not less than 0.998 9 and limits of detection(LOD) of 1-11 ng/mL.This method is convenient,sensitive and accurate,and is suitable for the determination and confirmation of 5 dyes in chilli powder．关键词：Para red;Sudan red;ultrasonic-assisted dispersive emulsion microextraction;high performance liquid chromatography(HPLC)
- 1984
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- 438
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发布时间：2023-05-18 - 摘要：Gold nanoparticles（AuNPs） were electrodeposited onto the surface of a glassy carbon electrode（GCE）.The antibody of microcystin （leucine arginine）（anti-MC-LR） was immobilized on the film surface of AuNPs by the adsorption between Au nanoparticles and antibody.Non specific adsorption sites on the AuNPs were blocked with bovine serum albumin（BSA） to prepare an immunoelectrode anti-MC-LR/AuNPs/GCE.Microemulsion polymerization method was adopted to synthesize silica nanoparticles doped with tris（2,2′-bipyridyl） ruthenium（Ⅱ） complex ions（e.g.Ru@SiO2）.Ru@SiO2 nanoparticles and AuNPs on the surface of a GCE were characterized by transmission electron microscopy image（TEM） and scanning electron microscopy（SEM）,respectively.The Ru@SiO2 nanoparticles were further modified with amino groups by reacting with 3-aminopropyltriethoxysilane.The amino group modified Ru@SiO2 was then crosslinked with the carboxylic groups of microcystin （leucine-arginine）（MC-LR） by ethyl-3-（dimethyl aminopropyl） carbodiimide（EDC） and N-hydroxysuccinimide（NHS） to prepare Ru@SiO2-conjugated MC-LR（MC-LR-Ru@SiO2）.The immunosensor was based on the direct competitive immunoassay format between the labeled agent of MC-LR-Ru@SiO2 and the analyte.In the presence of MC-LR-Ru@SiO2,tripropylamine（TPA） was used as coreactant.MC-LR in solution was determined by electrochemiluminescence（ECL） method.The ECL intensity（I） decreases with the increase of MC-LR concentration after antigen-antibody reaction.A good linear relationship between the change of ECL intensity（ΔI） and the logarithm of MC-LR concentration was obtained in the range of 0.100-100 μg/L with a detection limit of 0.007 μg/L.The developed ECL immunosensor was used to determine MC-LR in real water samples with recoveries of 95.5%-105%.关键词：Ru@SiO2;nanoparticles;microcystins;immunosensors;electrochemiluminescence
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发布时间：2023-05-18 - 摘要：A method for the quantitative analysis of 18 active components in Bansha herbal tea（BHT） by ultra high performance liquid chromatography coupled with tandem mass spectrometry（UHPLC-MS/MS） was developed.BHT samples were extracted with methanol,and the extracts were separated on an RRHD SB-C18 column with 0.5% formic acid aqueous solution-acetonitrile as mobile phase by gradient elution.Quantitative analysis was performed by a triple quadrupole MS system operated under multiple-reaction monitoring（MRM） mode in negative ion detection mode.The method showed a good linearity with correlation coefficients（r） not less than 0.996 4 for 18 investigated analytes.The limits of detection and quantitation were in the ranges of 0.001-0.08 μg/mL and 0.002-0.27 μg/mL,respectively.In addition,high precision,good accuracy,and desirable stability were also obtained.The developed method was then used for the determination of the contents of 18 active components in 11 Huangzhenlong（HZL） and 8 Pingantang（PAT） BHT samples.The results showed that the concentrations of 18 investigated active components ranged from 0.7 to 149.8 μg/mL and 0.9 to 110.3 μg/mL for HZL and PAT samples,respectively.Principal component analysis（PCA） was performed to evaluate the quality stability and consistency and trace the origins of the 19 batches of investigated BHT samples.PCA results showed that two manufactures BHT samples were easy to differentiate by using the PCA score plot,indicating that the formulas and the production processes of the two BHT products were different.The proposed method was a desirable approach for the quality assessment and control of BHT.关键词：ultra high performance liquid chromatography coupled with tandem mass spectrometry（UHPLC-MS/MS）;Bansha herbal tea（BHT）;active components;quantitative analysis
- 2026
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- 502
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发布时间：2023-05-18 - 摘要：A rapid method for the simultaneous determination of polyoxyethylene octylphenol ether（OPEO） and polyoxyethylene nonylphenyl ether（NPEO） was developed by using high performance liquid chromatography-mass spectrometry（HPLC-MS）.The samples were ultrasonically extracted with methanol.Chromatographic analysis was carried out on an Agilent Eclipse Plus C18（4.6 mm×100 mm,3.5 μm） column with 5 mmol/L ammonium acetate solution-methanol as mobile phase in gradient program,and the quantitation was performed by the matrix-matched external standard method.The standard addition recovery experiments were conducted on two different kinds of wall coating（A and B）.The calibration curves showed good linearities in the concontration range of 0.1-5.0 mg/L with correlation coefficients greater than 0.99.The recoveries of alkylphenol ethoxylates at three spiked levels ranged from 83.8% to 114.5%,with relative standard deviations（RSDs,n=6） of 1.3%-9.8%.The quantitation limits were between 4.0 mg/kg and 5.5 mg/kg.The method is simple,time-saving and environmental friendly with high sensitivity and good reproducibility,and has a practical application value due to its low-cost and short-circle.关键词：high performance liquid chromatography-mass spectrometry(HPLC-MS);coating;alkylphenol ethoxylates
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发布时间：2023-05-18 - 摘要：A gas chromatography-tandem mass spectrometric（GC-MS/MS） method was developed for the analysis of 20 polychlorinated biphenyls（PCBs） and polycyclic aromatic hydrocarbons（PAHs） in milk.The sample was cleaned up with Cleanert BaP SPE column.The target compounds were eluted by n hexane,and then analyzed by GC-MS/MS.The results showed that target analytes displayed good linear relationships over concentration range of 5-200 μg/L,with correlations coefficients more than 0.99.The quantitation limits were all 1.0 μg/kg.The average recoveries of 20 compounds at three spiked levels of 1.0,2.0,5.0 μg/kg ranged from 67.3% to 106.9%,with relative standard deviations（RSD） of 3.1%-13.9%.With the advantages of simplicity,rapidness and accuracy,the method is applicable for the determination of PCBs and PAHs in milk,and provides a guarantee for quality control and safety evaluation of milk.关键词：gas chromatography-tandem mass spectrometry（GC-MS/MS）;polychlorinated biphenyls（PCBs）;polycyclic aromatic hydrocarbons（PAHs）;milk
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- 431
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发布时间：2023-05-18 - 摘要：A novel method was proposed for the determination of oxytetracycline by capillary electrophoresis（CE） with electrochemiluminescent（ECL） detection based on the enhancement effect of ECL intensity in the tris（2,2’-bipyridine） ruthenium（Ⅱ）（Ru（bpy）2+3-ECL） system by oxytetracycline.The sensitivity was further improved by 3.5 fold by the field amplified sample injection technique.The best result was achieved with a sampling voltage of 10 kV and an injection time of 6 s in 8 mmol?L-1 borate buffer（pH 8.0） at a detection voltage of 1.22 V.The consumed time for one run was about 9 min.A linear range of 20-200 μg?L-1（r=0.995 3） with a limit of detection（S/N=3） of 5 μg?L-1 was obtained by the proposed method.The intra-day relative standard deviations（RSDs） of relative ECL intensity and migration time for five replicated trials of 100 μg?L-1 oxytetracycline were 2.4% and 2.1%,respectively,and the inter-day RSDs of relative ECL intensity and migration time for five replicated trials of 100 μg?L-1 oxytetracycline were 3.6% and 2.8%,respectively.The developed method was successfully applied in the detection of oxytetracycline residue in a honey sample.The average recoveries were in the range of 91.5%-105.2% at spiked levels of 200,1 000,2 000 μg?kg-1.The limit of detection for the proposed method was 10 μg?kg-1 in honey matrix,which was lower than the maximum residue limit of oxytetracycline in food.The results indicated that the proposed method had an application potential in food analysis.关键词：capillary electrophoresis-electrochemiluminescence;tris（2,2’-bipyridyl） ruthenium（Ⅱ）;oxytetracycline;honey
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发布时间：2023-05-18 - 摘要：In this paper,a novel method to detect single DNA molecule was proposed.A sandwich-type hybridization assay was performed on a streptavidin-coated substrate.A large number of biotinylated capture DNAs（c-DNAs） were first covalently bound to the substrate through the interaction between streptavidin and biotin.Then,the complementary target DNAs（t-DNAs） were hybridized with the c-DNAs attached to the substrate,followed by hybridization between t-DNAs and biotinylated first probe DNAs（p-DNAs） conjugated to streptavidin coated magnetic microparticles（MMPs）.In this case,one t-DNA binding one MMP could be observed with an optical microscope.The number of the MMPs is linearly proportional to concentration of t-DNA in the range of 5×10-16-1×10-14 mol/L.This size amplification method was simple and could be applied in other biomolecules.关键词：magnetic sphere;volume amplification;DNA;single molecule detection
- 1900
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- 406
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发布时间：2023-05-18 - 摘要：A gas chromatography-mass spectrometric（GC-MS） method was developed for the simultaneous determination of toluene,o-xylene,m-xylene,p-xylene,N,N-dimethyl formamide(DMF) and dimethyl sulfoxide(DMSO) residues in agro products.The target compounds were extracted from various vegetables and crops by acetonitrile solution,and further analyzed by GC-MS in selected ion monitoring after chromatographic separation on an Agilent DB-624（30.0 m×250 μm×1.4 μm） column.Identification was achieved by the retention time and the ion ratio,and quantification was done by the external standard method.The results showed that the calibration curves were linear in the range of 0.005-0.500 mg/L for toluene,p-xylene,o-xylene and m-xylene,0.025-0.125 mg/L for DMF,and 0.050-0.500 mg/L for DMSO,with correlation coefficients of 0.992 0-0.997 1.The spiked recoveries of six organic solvents residues were in the range of 60.1%-115.2% with relative standard deviations（RSDs） not more than 11.0%.The limits of detection were in the range of 0.002-0.050 mg/kg for benzene series,0.010-0.025 mg/kg for DMF,and 0.060-0.150 mg/kg for DMSO.The method is simple,rapid,sensitive and accurate,and could be used for the simultaneous determination of volatile organic solvents residual in agricultural products.关键词：gas chromatography-mass spectrometry（GC-MS）;organic solvents;agricultural products;liquid-liquid extraction
- 2126
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- 483
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发布时间：2023-05-18 - 摘要：The reaction between NaHSO3 and H2O2 produced ultra-weak chemiluminescence(CL).Riboflavin could greatly enhance the CL from NaHSO3-H2O2 system.The CL intensity was linearly increased with concentration of riboflavin in the range of 0.02-2.0 μg/mL.Based on the phenomenon,a high sensitive chemiluminescent method was developed for the determination of riboflavin in tablet samples.The detection limit was 0.007 μg/mL and the relative standard deviation was not more than 1.6%.Furthermore,fluorescent and chemiluminescent spectrum was utilized to illustrate the chemiluminescent mechanism,which would extend the application of NaHSO3-H2O2 system.关键词：chemiluminescence;sodium bisulfite;hydrogen peroxide;riboflavin
- 2257
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- 443
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- 1
发布时间：2023-05-18 - 摘要：A method of aptamer-based detection of kanamycin was established by using a graphene modified glassy carbon electrode.Kanamycin specific aptamer(Kana-aptamer) could be adsorbed onto the graphene(Gr) modified electrode,which prevents the electron transfer between the probe［Fe（CN）6］3-/4- and the electrode.However,after incubation with samples containing kanamycin,kanamycin could bind with aptamer and replace it from the electrode,which in turn declines the resistance of the electron transfer and recovers the electrochemical signal.The procedure was firstly characterized by cyclic voltametry（CV） and atomic force microscopy.Then this replacement effect was utilized-to-electrochemically determine kanamycin.Under the optimized conditions,kanamycin could be determined by differential pulse voltammetry（DPV）,and the calibration curve was linear in the range of 1×10-6-1×10-5 mol/L,with a detection limit of 5×10-7 mol/L.The method was successfully applied in the detection of kanamycin in milk samples with satisfactory result.关键词：kanamycin;aptamer;graphene;glassy carbon electrode
- 2057
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- 350
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发布时间：2023-05-18 - 摘要：A method of extraction for heliotrine and lasiocarpine was developed using microwave irradiated solvent reflux extraction(MISRE).The single factor test was used to optimize the experimental conditions.The optimum extraction conditions were as follows:100 mesh size of material，microwave power：60%,microwave irradiated time：90 seconds；solvent-materail ratio：1∶25;extraction temperature：90 ℃;extraction time:45 min.Heliotrine and lasiocarpine were determined by HPLC using acetonitrile-0.1% acetic acid（pH 5.6，5∶95） as mobile phase at a detection wavelength of 220 nm.The linear ranges of lasiocarpine and heliotrine were in the range of 50-900 mg/L，with detection limits of 1.50 mg/L and 1.52 mg/L,respectively.The recoveries were in the ranges of 95.0%-98.5% and 96.5%-101%,with RSDs of 1.8% and 2.4%，respectively.The method was simple and highly sensitive.关键词：microwave irradiated solvent reflux extraction(MISRE);Cynoglossum amabile Stapf et Drumm;heliotrine;lasiocarpine;high performance liquid chromatography（HPLC）
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发布时间：2023-05-18 - 摘要：A high performance liquid chromatography-tandem mass spectrometric method with on-line SPE(solid phase extraction) was established for the determination of 5 quinoxaline residues in feed.2 g feed was extracted with 10 mL 0.1% HCl-CH3OH(1∶1).The extract was 10 times diluted with 0。2% formic acid.The dissolution was enriched and purified with a reverse phase on-line SPE column on a double ternary liquid chromatograph.Target compounds were eluted with 0.2% formic acid and acetonitrile by gradient elution,and separated with an octadecyl silica bonded column.Target compounds were then determined by tandem mass spectrometry.The results showed that the linearities of 5 quinoxalines were good in the range of 50-25 000 μg/kg(r＞0.999).The LOD of the method was 25 μg/kg,and LOQ was 50 μg/kg.Recoveries of 5 quinoxalines were in the range of 72.6%-84.6%,while RSDs of both in the batch and between the batch were all lower than 10%.The method was proved to be more convenient,economical and stable than the traditional column SPE method.关键词：on-line SPE;double ternary liquid chromatography-tandem mass spectrometry;quinoxalines;feed
- 2140
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发布时间：2023-05-18 - 摘要：In recent years,more and more attention has been focused on dispersive liquid-liquid microextraction（DLLME） which appeared as a new liquid-phase microextraction（LPME） technique.DLLME has been widely applied in the extraction of both inorganic and organic analytes from different matrices due to its simplicity of the procedure,low solvent consumption,and high enrichment factors from a wide gap between acceptor and donor phases.However,several innate drawbacks of DLLME like toxic extractant solvents used or a poor selection has restricted the technique’s use in certain fields.Recent developments in DLLME operation mode,e.g.,low density solvent-based DLLME,DLLME based on solidification of floating organic drop,the use of an auxiliary solvent for adjustment of density of extraction mixture,the application of ionic liquid-based DLLME,and reversed-phase DLLME by using water as extractant in determination of some species in food are presented in the review.This work also describes the principle,procedure and influence factors including the type and volume of extractants and dispersers,the sample solution pH value,addition of salt and extraction time of this method.关键词：dispersive liquid-liquid microextraction（DLLME）;food analysis;application;review
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发布时间：2023-05-18
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