最新刊期
卷 36 ， 期 4 ， 2017
- 摘要：An analytical method for the simultaneous determination of 322 pesticides and chemical pollutants in Pinellia was established based on optimized dispersive solid phase extraction sample preparation method with gas chromatography-quadruple time of flight mass spectrometry（GC-Q-TOF/MS）.The influences of different extraction solvents,buffer salt systems and purifing agents on the recoveries of pesticides and chemical pollutants were investigsted.The pesticides and chemical pollutants in the samples were extracted with acetonitrile containing 1% acetic acid and acetic acid-sodium acetate，then cleaned up with mixed sorbents and analyzed by GC-Q-TOF/MS under TOF mode.The results showed that 84.2% of the 322 pesticides and chemical pollutants were limited to 5μg/kg and 14.6% of the pesticides and chemical pollutants were screened to 10 μg/kg. The recoveries at the spiked levels of 10，50,100 μg/kg were in the ranges of 70.2%-119.5%,70.6%-119.8% and 70.2%-119.9%, respectively. The relative standard deviations（RSD） were 0.2%-19.7%,0.2%-19.5% and 0.5%-20.0%，respectively. Compared to the original DSPE method,the proposed method was more efficient,rapid,sensitivie and accurate. It is suitable for the rapid screening and quantitative analysis of 322 pesticide residues and chemical pollutants in Pinellia.关键词：dispersive solid phase extraction（DSPE）;GC-Q-TOF/MS;Pinellia;multi-residue pesticides
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发布时间： -
Determination of Mycotoxins in Cereals by UPLC-Quadrupole/Orbitrap High Resolution Mass Spectrometry
摘要：A UPLC-Quadrupole/Orbitrap high-resolution mass spectrometric(HRMS) method with stable isotope dilution technique was established for the determination of 16 mycotoxins in cereals.The sample was extracted with acetonitrile-water-acetic acid(70∶29∶1,by volume).The mycotoxins were separated on a C18 column, and quantified in full scan mode.The method showed good linearities(r2＞0.999) in a certain concentration range.The average recoveries and RSDs of mycotoxins in 4 kinds of cereals(wheat,maize,rice and barley) were in the range of 75.3%-123.5% and 0.41%-14.7%,respectively.The method was simple and accurate,and was suitable for the daily monitoring of mycotoxins.关键词：mycotoxins;high resolution mass spectrometry(HRMS);cereals;stable isotope dilution- 940
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发布时间： - 摘要：A method was established to analysis volatile components in pulp and peel of bananas based on cryogenic frozen liquid-liquid extraction/GC-MS combined with retention index.The volatile components in bananas were extracted by a cryogenic frozen liquid-liquid extraction pretreatment method.39 kinds of volatile components in banana pulp and 32 volatile components in banana peel were identified, respectively. The main ingredients were esters. However,there were differences in the types and relative contents of the volatile components between pulp and peel.The main components in banana pulp were propionic acid ethyl ester(11.88%),isoamyl acetate(9.45%),hexadecanoic acid(8.71%),isovaleric acid butyl ester(7.79%), secondary amyl acetate(5.29%),while the major components in banana peel were isoamyl butyrate(22.85%), hexadecanoic acid(15.91%), stearic acid(6.86%), 4-allyl-2,6-dimethoxy phenol(6.83%),linolenic acid(6.34%).There were 19 kinds of components in both banana pulp and banana peel,such as isoamyl alcohol,isobutyl acetate,butyric acid,acetic acid and isoamyl para amyl.关键词：low temperature frozen liquid-liquid extraction;gas chromatography-mass spectrometry(GC-MS);retention index;banana pulp;banana peel;volatile components
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发布时间： - 摘要：The magnetic polystyrene-chloromethyl styrene material（Fe3O4@SiO2@DVB-VBC） was synthesized by in situ polymerization initiated with 2,2-azobisisobutyronitrile(AIBN).4-chloromethyl styrene(VBC) and divinylbenzene(DVB) were chosen as monomer and crosslinking agent, respectively. Magnetic γ-methacryloxypropyltrimethoxysilane（MPS） modified silica microspheres were used as the cores. The mixture of toluene and polyethylene glycol 2000（1∶2,by mass） was used as the combined porogen. The structure and composition of Fe3O4@SiO2@DVB-VBC material were characterized by Fourier transform infrared spectroscopy（FT-IR）,X-ray diffraction（XRD） and nitrogen physical adsorption.The enrichment performance of Fe3O4@SiO2@DVB-VBC material was investigated by using anthracene as the target compound.The result indicated that the adsorption ability of the material could be affected by the mass ratio of monomers and crosslinking agent.Under the condition that the mass ratio of monomers and crosslinking agent was set by 1∶4,the prepared material showed the best adsorption performance for anthracene.The pore structure of the material could affect the adsorption equilibrium time.The adsorption equilibrium for authracene was achieved within 30min,and the adsorption rate was calculated to be 95%.The adsorption mechanism between aromatic compounds and the prepared adsorbentis depended mainly on the hydrophobic interaction.The study of adsorption kinetics indicated that the adsorption behavior fitted well with the pseudo first-order kinetics model.99% anthracene could be eluted from the absorbent by using 2mL of acetonitrile within 15min.关键词：magnetic polystyrene-chloromethyl styrene material;anthracene;adsorption
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发布时间： - 摘要：Two methods,including Mg(OH)2 co-precipitation and direction dilution,were compared in the determination of multiple major/trace elements in sea water by inductively coupled plasma mass spectrometric (ICP-MS) method.Suitable analytical methods were defined respectively to provide practical means for the determination of these elements in seawater by ICP-MS.The results showed that,Mg(OH)2 co-precipitation could achieve the separation,enrichment and accurate determination of 19 elements including V,Cr,Mn,Co,Cd and rare elements(La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu)， while 10 fold direct dilution method could be accurately and simultaneously used to determine 13 major/trace elements including B,Sr,Li,Rb,I,V,Cr,As,Cd,U,Mo,Cu,Mn,but it is not suitable for the detection of Zn,Ni,Co,Pb and low concentration elements like rare earth elements.The two methods are suitable for simple and rapid determination of elements with high accuracy and precision.Combining the two methods together,accurate determination of 28 elements,including Co,La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu(15 elements,by Mg(OH)2 co-precipitation) and B,Sr,Li,Rb,I,V,Cr,As,Cd,U,Mo,Cu,Mn(13 elements,by 10 fold direct dilution) could be achieved with about 50mL of offshore and open sea water.关键词：Mg(OH)2 co-precipitation;direct dilution;ICP-MS;elements determination;sea water
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发布时间： - 摘要：An optical nanosensor based Mn doped ZnS quantum dots（QDs）was synthesized using 6-hydroxynictinic acid（6-HNA） as template via surface molecular imprinting sol-gel method.Fourier transform infrared spectroscopic（FT-IR） spectra and scanning electron microscopic（SEM） images showed that the imprinted polymer was successfully grafted onto MIP-QDs.Adsorption tests revealed that the affinity and selectivity of MIP-QDs for 6-HNA were significantly higher than its analogues nicotinic acid and coumalic acid.Under the optimized conditions,a phosphorescent sensor for detecting 6-HNA was constructed.The linear range for detection of 6-HNA was in the range of 3.4-67.0 μmol/L with a detection limit of 1.03 μmol/L and a correlation coefficient（r2） of 0.996 5.Recoveries of 91.0%-103.9% and relative standard deviations less than 4.5% were achieved in real samples,which were in good agreement with that of the high performance liquid chromatographic（HPLC） method（P>0.05）.The proposed method had good veracity and feasibility.关键词：quantum dots;molecular imprinting;phosphorescence detection;6-hydroxynicotinic acid（6-HNA）;nicotinic acid
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发布时间： - 摘要：Basic nitrogen compounds in diesel distillated from Xinjiang Baoming shale oil were concentrated by methods of solvent extraction refining and column chromatography,etc.The solvent refining method was used to separate diesel distillated from Xinjiang Baoming shale oil into extract oil.The solvent in the method of solvent extraction refining was furfural.The basic nitrogen compounds in the extract oil were concentrated preliminarily.Basic nitrogen compounds were obtained from the extract oil by column chromatography,and analyzed by Fourier transform infrared spectroscopy（FT-IR） and gas chromatography-mass spectrometry（GC-MS）.The results showed that basic nitrogen compounds in diesel distillated from Xinjiang Baoming shale oil were gradiently concentrated by methods of solvent refining and column chromatography.The percentage content of basic nitrogen compounds was increased from 12.08% in the extract oil to 69.48% in the product of enrichment,and 60 kinds of basic nitrogen compounds in the concentrated products were identified.The main components in the basic nitrogen compounds were aniline,quinoline and pyridine compounds,and their percentage contents were 25.85%,23.56% and 16.52%,respectively.关键词：shale oil;solvent refining;column chromatography;concentrated;GC-MS;basic nitrogen compounds
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发布时间： - 摘要：An analytical method was developed for the identification and detection of semicarbazide(SEM) residues in flour and flour products by high performance liquid chromatography coupled to quadrupole/linear ion trap mass spectrometry(HPLC-QTRAP/MS).Samples were reacted with o-nitrobenzaldehyde in HCl with assistant of ultrasonic to produce stable derivative,and then the derivative was cleaned up with PLS SPE cartridge,eluted with ethyl acetate.The separation of analytes was carried out on a Shim-pack XR-ODS Ⅲ C18 column(2.0 mm×50 mm,1.6 μm) using mobile phases of 0.1%(by volume) formic acid in ultrapure water and methanol solution by gradient elutionA multiple reaction monitoring(MRM) scan mode and an enhanced product ion(EPI) scan mode as dependent in an information dependent acquisition(IDA) experiment were used in mass spectrometry acquisition．Lab-built EPI library and the internal standards were adopted for the identification and quantification．The results indicated that the calibration curve of SEM showed a good linearity(r=0.996) whithin the range of 0.5-40 μg/L.The limit of detection(LOD,S/N=3) for SEM was 0.10 μg/kg,and the limit of quantitation(LOQ,S/N=10) was 0.25 μg/kg．The average recoveries of SEM at four spiked levels of 0.25,0.5,2.0,10.0 μg/kg were in the range of 89.1%-112.8% with relative standard deviations(RSDs) of 1.4%-8.6%.With high sensitivity and good recovery,the proposed method was effectively used to identify and detect the residues of semicarbazide in flour and flour products.关键词：quadruple/linear ion trap mass spectrometry(HPLC-QTRAP/MS);semicarbazide;ultrasonic assisted derivatization;flour and flour products
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发布时间： - 摘要：A method was developed for the simultaneous determination of eight fat soluble colorants(para red,sudan Ⅰ,Ⅱ,Ⅲ,Ⅳ,sudan red 7B,sudan red G and sudan yellow) in feed by liquid chromatography-tandem mass spectrometry(LC-MS/MS) combined with dispersive solid phase extraction.The samples were extracted with acetonitrile.Then the extract was purified by dispersive solid phase extraction method with N propylethylenediamine(PSA) sorbent.After purification,the extract was diluted with 0.2% formic acid solution.Before analysis by LC-MS/MS,the samples were separated on an Acquity BEH C18 column with a mixture of 0.2% formic acid solution and acetonitrile as mobile phase under gradient elution conditions.The mass spectrometer was operated under multiple reaction monitoring(MRM) mode in the positive mode.The samples were quantified by the isotope dilution and the internal standard method.Good linearities were obtained for the eight fat soluble colorants in the concentration range of 1.0-200 μg/L with correlation coefficients more than 0.998.The recoveries of the analytes at fortified levels of 10-500 μg/kg were in the range of 102%-111%.The limits of detection and the limit of quantitation for eight fat soluble colorants were 5.0 μg/kg and 10 μg/kg,respectively.The relative standard deviations of intra-assay were between 2.8% and 8.0%.The relative standard deviations of inter assay were between 2.8% and 7.8%.The method is suitable for the determination of eight fat soluble colorants in feed.关键词：dispersive solid phase extraction;feed;fat soluble colorants;liquid chromatography with tandem mass spectrometry(LC-MS/MS);residue
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发布时间： - 摘要：A multiresidue analytical method was developed for the rapid detection of 36 pesticides in peanut using ultra high performance liquid chromatography-tandem mass spectrometric technique(UHPLC-MS/MS).Peanut samples were extracted with acetonitrile,and then cleaned up with QuEChERS EMR-Lipid.The extract was detected by UHPLC-MS/MS.The positive ion mode and multiple reaction monitoring(MRM) mode were used to identify and quantify 36 pesticide residues in peanut.All pesticides had good linearity with correlation coefficients above 0.994.The average recoveries of the 36 pesticides ranged from 70.4% to 119% with relative standard deviations(RSDs) of 1.3%-19.4% at spiked levels of 0.005,0.01,0.10 mg/kg.The quantitation limits of this method were in the range of 0.002 5-0.05 mg/kg. With the advantages of simplicity,rapidness,sensitivity and good purifying effect,the method was suitable for the rapid determination of pesticide residues in peanut.关键词：pesticide residues;peanut;enhanced matrix removal;ultra high performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS)
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发布时间： - 摘要：In this work,based on the continuous heating measure by DXR laser microscopic Raman spectrometry,the change regulations of the Raman feature peaks of ester base oils,such as trimethylolpropane trioleate（TMPTO）,tridecyl trimellitate（TDTM） and dioctyl adipate（DOA） were investigated under online heating condition.Changing characteristics of ester oil molecular structure during the thermal oxidation process were studied.The results showed that some Raman peak positions and Raman intensity of ester oil varied with the increase of heating temperature.The C—H stretching vibration peak of methyl and methylene and the shear vibration peak of methylene of ester base oil are very sensitive to temperature.With the increase of temperature,the peak intensity has different degrees of weakening but could basically recover after cooling down.There is no obvious variation on C‖O vibration peak with the increase of temperature.The C‖C stretching vibration peak position of TMPTO ester base oil gradually shifts to higher wave region with the increase of temperature and will recover after cooling.Under the isothermal condition,the Raman intensity of TDTM base oil has no obvious change,the Raman intensity of C—H stretching vibration peak of methylene of DOA ester base oil and the Raman intensity of ‖C—H,C‖C and—CH2— of TMPTO ester base oil decrease with the increase of oxidation time.Therefore,in situ Raman spectroscopy could be used to monitor the continuous thermal oxidation process of unsaturated ester oils,but it has some limitations in the monitoring of high temperature oxidation of saturated ester oil and aromatic ester oil.关键词：ester base oils;thermal oxidation;molecular structure;Raman spectroscopy
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发布时间： - 摘要：This work describes the development of a sensitive and reliable method using QuEChERS sample preparation and high performance liquid chromatography-diode array detector(HPLC-DAD) for simultaneous determination of phytohormones, zeatin(Z), gibberellic acid(GA), paclobutrazol(PBZ), 4-fluorophenoxyacetic acid(4-FPA), 4-chlorophenoxyacetic acid(4-CPA), 3-indolyl-acetic acid(IAA), 3-indolyl-butyric acid(IBA), 6-benzylaminopurine(6-BA), abscisic acid(ABA), 1-naphthyl acetic acid(NAA), forchlorfenuron(CPPU), 2,4-dichlorophenoxyaceticacid(2,4-D), 2,4,5-trichlorophenoxyacetic acid(2,4,5-T), in fruits and vegetables.The samples were extracted with 80% acetonitrile containing 0.5% acetic acid,and the extract was cleaned up with dispersive solid phase extraction adsorbent(powder of C18 and diatomaceous earth).The phytohormones were separated on a Waters XBridge C18,and eluated utilizing a gradient elution program of acetonitrile and water containing 0.05% acetic acid(by volume) as mobile phase.The correlation coefficients of calibration curves were over 0.99 in the corresponding concentration ranges.The average recoveries of the 13 analytes at three spiked concentration levels varied from 68.4% to 95.1% with relative standard deviations(RSD) less than 5%.The limits of detection(LOD) and quantitation(LOQ) were in the ranges of 0.005-0.020 mg/kg and 0.01-0.09 mg/kg,respectively.The real sample tests showed that the proposed method was simple,rapid,reliable and cost-effective,and was suitable for the simultaneous determination of phytohormones in fruits and vegetables.关键词：QuEChERS;high performance liquid chromatography(HPLC);phytohormones;fruits and vegetables
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发布时间： - 摘要：A nano-silver/poly quercetin composites modified paraffin-impregnated graphite electrode was prepared by electrochemical method(Ag/Qu/WGE).A mixture of L-Thr,chitosan and Nafion was coated on the surface of Ag/Qu/WGE,L Thr(template molecule) was removed by electrochemical cleaning using potentiostatic method.As a result,a molecular imprinted polymer modified electrode based on chitosan/nano-silver/poly quercetin composites could be obtained for L-Thr detection(TMIP/WGE).The characteristics of the modified electrode were investigated by means of field emission scanning electron microscope technique,X-ray photoelectron spectroscopy,infrared spectra and electrochemical technique.The result indicated that the TMIP/WGE displayed a good electro-catalysis towards the oxidation of L-Thr,which could be used for sensitive and quick detection of L-Thr.The differences of oxidation peak current of L-Thr(1.45 V) showed a good linearity in the concentration range of 0.1-1.0 μmol/L with a detection limit(3σ) of 0.01 μmol/L.The electrode was successfully applied in the determination of L-Thr in fermentation broth.关键词：L-threonine(L-Thr);molecular imprinted polymer;nano-silver
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发布时间： - 摘要：A simple and sensitive electrochemical sensor was fabricated for the detection of Pb2+ based on L-cysteine（L-Cys）/CdTe quantum dots（QDs） hybrid nanocomposites modified gold electrode（GE）.CdTe QDs were synthesized in aqueous phase.Then,carboxyl labeled CdTe QDs were covalently bonded to L-cysteine on gold electrode,depending on connection between-COOH on MPA-CdTe surface and —NH2 in L-cysteine.The morphology and composition of CdTe QDs and hybrid nanocomposites were characterized by fourier transform infrared spectroscopy（FTIR）,X-ray powder diffraction（XRD）,transmission electron microscopy（TEM）,UV-Vis and fluorescence spectrometry.The electrochemical performance of L-Cys/CdTe nanocomposite and the optimized self-assembly time of CdTe QDs on electrode were investigated by cyclic voltammetry（CV）.The electrochemical behavior of lead ions at L-Cys/CdTe nanocomposite modified gold electrode was investigated by different pulse stripping voltammetry（DPSV）.Under the optimal hybridization conditions,different pulse stripping voltammetric responses of L-Cys/CdTe/GE sensor were in linearity with Pb2+ in the concentration range of 1.0×10-6-1.0×10-2 mol/L with a detection limit of（3σ,n=5） 4.0×10-7 mol/L and a correlation coefficient（r2） of 0.993 8.Therefore,the electrochemical sensor modified with L-Cys/CdTe/GE nanocomposites exhibited the advantages of high sensitivity,good reproducibility and stability,providing a potential platform for the fabrication of other electrochemical sensors.关键词：CdTe QDs;L-cysteine;modified electrode;electrochemical sensor;lead ions
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发布时间： - 摘要：The on-line detection technology of heavy metals in surface water was established by the on-line preconcentration and the on-line thermal digestion method based on microwave plasma atomic emission spectrometry（MP-AES）.The heavy metal elements（Cd,Cu,Cr,Ni,Pb,Fe,Mn and Zn） in water samples were in situ monitored simultaneously in Xijiang River,one of the Pearl River main streams.The results showed that the on line detection technology could meet the requirements of surface water environment quality standard（GB 3838-2002） for quantitative detection of those heavy metals.According to the analytical results of heavy metal elements in the environmental standard samples,the determination results were consistent with the standard values.The recoveries of spiked water samples ranged from 81.5%to 102%.The detection limits of this detection technology for heavy metals ranged from 1.14 μg/L to 5.34 μg/L,and the RSDs of the detection results were in the range of 0.79%-9.4%.The method could meet the requirements for rapid,continuous and accurate monitoring of heavy metal element contents in surface water.关键词：microwave plasma atomic emission spectrometry（MP-AES）;surface water;heavy metal;online monitoring
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发布时间： - 摘要：A multistage liquid-liquid microextraction(LLME) coupled with GC-MS method was developed to determine squalene in Chinese liquor.After diluting the liquor sample,a multistage microextraction was carried out using pentane-diethyl ether mixture(1∶3,by volume),then the organic phase was concentrated with nitrogen,and analyzed by GC-MS.The result indicated that squalene had a good linearity in the range of 0.62-159.88 μg/L,with a correlation coefficient of 0.995 5.The detection limit of squalene was as low as 0.17 μg/L.The average recoveries of squalene at spiked levels of 2,20,40 μg/L were 78.1%,85.0%,103.5%,respectively,with relative deviations of 12.1%,8.9%,7.0%,respectively.With the advantages of simplicity,accuracy,high-extraction efficiency and low consumption of organic solvent,this method was suitable for the quantitative analysis of squalene in Chinese liquor.关键词：squalene;Chinese liquor;multistage LLME;GC-MS;quantitation analysis
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发布时间： - 摘要：A method was developed for the determination of amitraz,chlordimeform and their metabolites in blood by gas chromatography-tandem mass spectrometry(GC-MS/MS).The conditions for sample pretreatment and GC-MS/MS parameters were optimized.The samples were pretreated by solid supported liquid extraction(SLE),and eluted with acetonitrile-dichloromethane(1∶1).The detection was carried out by GC-MS/MS in multiple reaction monitoring(MRM) mode.Good linear relationships for 2,4-dimethylaniline(DMA),4-chloro-2-methylaniline and amitraz were obtained in the range of 1.0-1 000 ng/mL,and those for other three compounds were obtained in the range of 2.0-1 000 ng/mL,with correlation coefficients more than 0.99.The limits of quantitation were in the range of 1.0-2.0 ng/mL,and the recoveries ranged from 88.6% to 113%.With the advantages of simplicity,rapidness,low sample consumption,accuracy and reliability,this methed is suitable for the determination of six compounds in blood.关键词：gas chromatography-tandem mass spectrometry(GC-MS/MS);solid supported liquid extraction;blood;chlordimeform;amitraz;metabolites
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发布时间： - 摘要：Synthesis methods of hydroxyapatite with different calcium sources under hydrothermal conditions were compared.From SEM,XRD and FT-IR results,it is concluded that the eggshell could be used as an effective source of Ca2+,and its porous structures could also be selected as a hard template in the formation of flower like hydroxyapatite.Sodium dihydrogen phosphate was used as the sources of PO3-4 to corrode the CaCO3 to hydroxyapatite.The result indicated that the sodium phosphocreatine would have a wide application prospect in the synthesis of high purity hydroxyapatite by hydrothermal decomposition.关键词：hydroxyapatite;eggshell;sodium phosphocreatine;hydrothermal reaction
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发布时间： - 摘要：A method was developed for the determination of 8 kinds of dinitroaniline herbicides,including trifluralin,pendimethalin,butralin,isopropalin,dinitramine,nitralin,oryzalin and prodiamine in complex matrices(tea,soybean and chicken livers) by ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).Qualification and confirmation were achieved by electro spray ionization(ESI) in positive mode using multiple reaction monitoring(MRM),and the external standard method was uesd for quantitation.The limits of quantitation were all 0.010 mg/kg.The recoveries of dinitroaniline herbicide residues were between 75.9% and 113% at spiked levels of 0.010-0.100 mg/kg.The RSDs of the method were between 1.7% and 19.0%.The method is precise and sensitive,and is suitable for both confirmation and quantification of trifluralin,pendimethalin,butralin,isopropalin,dinitramine,nitralin,oryzalin,prodiamine in tea,soybean and chicken livers.关键词：dinitroaniline herbicides;complex matrix;ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)
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发布时间： - 摘要：A high sensitive and selective electrochemical DNA sensor for E-coli was prepared by using NaOH etched glassy carbon electrode(GCE) as the substrate.Carboxyl was brought to the surface of GCE via NaOH etching,which improved DNA probes surface density.DNA probes was immobilized on the surface of GCE through the peptide bond.The sensitivity and selectivity of the sensor were characterized by cyclic voltammetry(CV) and differential pulse voltammetric(DPV) methods.The sensor shows a high sensitive and selective response to ssDNA of E-coli,and its linear range was 12.5-62.5 nmol/L with a detection limit of 1.20×10-9 mol/L.关键词：E-coli;NaOH etching;electrochemical biosensor
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发布时间： - 摘要：A gas chromatography-tandem mass spectrometric method was developed for the determination of 9 nitrogen containing compounds in marine fuel oil.The sample was purified with SPE cartridge to remove the saturated hydrocarbon,and then eluted with a mixed solution composing of dichloromethane and ethanol(5∶1).The target ingredients were separated on a DB-5MS column(30 m×0.25 mm×0.25 μm),detected in multiple reaction monitoring mode(MRM),and quantified by the external standard method.The method indicated a perfect performance in chromatographic separation.The linear ranges of 9 nitrogen containing compounds were between 1 mg/kg and 1 000 mg/kg,and the limits of quantitation were between 0.18 mg/kg and 0.43 mg/kg.The recoveries ranged from 85.3% to 121.6%,with relative standard deviations(RSDs,n=6) less than 6.8%.This method was rapid,accurate,precise and convenient to operate,and it was appropriate for the determination of 9 nitrogen containing compounds in marine fuel oil.关键词：marine fuel oil;nitrogen-containing compounds;gas chromatography-tandem mass spectrometry
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发布时间： - 摘要：A kind of aptamer biosensor was prepared to detect adenosine,with magnetic microspheres as the carrier immobilizing adenosine binding aptamer,then assembling adenosine aptamer digoxin labeled part complementary strand of adenosine binding aptamer（report DNA） on the surface.After adding adenosine,the anti-digoxin alkaline phosphatase（ALP）reacted with it,which could result in a change of chemiluminescence（CL） signal.Adenosine was quantified according to the change of the CL intensity.Factors affecting the assembly and recognition process,including amount of magnetic microsphere,aptamer,report DNA and ALP labeled anti digoxin, were studied.The results showed that under the optimal conditions,the concentration of adenosine was linear to CL intensity in the range of 1.0×10-7-1.0×10-3 mol/L with a detection limit of 1.0×10-7 mol/L.The result showed that this method had a better specificity to adenosine than other nucleosides,and was capable of selectively detecting quantities of adenosine in a complex environment（serum）.关键词：aptamer;magnetic microsphere;adenosine;chemiluminescence
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发布时间： - 摘要：Chiral compounds have been increasingly applied in many fields such as pharmaceutics,asymmetric synthesis,and biological and clinical analysis.The development of a high efficient and sensitive technique is an urgent demand for the rapid determination of compositions of enantiomers.Chiral fluorescent sensors as a sensitive fast effective detection tool have attracted a high attention.Various chiral fluorescent sensors with high enantioselective and sensitive recognition for chiral compounds have been developed.In this paper,the recent progress of chiral fluorescent sensors with binol derivatives,calixarenes,polymers,nanomaterials,metal orgaic porous materials as the units for chiral enantiomers are reviewed and their applications are summarized.Also,the future trends of chiral fluorescent sensors are proposed.关键词：chiral compound;enantiomer recognition;fluorescent sensor;review
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