最新刊期
卷 33 ， 期 3 ， 2014
- 摘要：A method was developed for the screening and confirmation of 28 illegally added phosphodiestrase-5 inhibitors（PDE-5） including sildenafil，tadalafil，vardenafil and analogues in health foods by liquid chromatography-ion trap-time of flight tandem mass spectrometry（LC-MS-IT-TOF）．The accurate mass and multiple-stage mass spectrometry databases of 28 compounds were established.The analytes in samples were extracted with methanol and separated on a C18 column（150 mm×4.6 mm,3.5 μm） by gradient elution using acetonitrile-0.1% acetic acid as mobile phase.The results showed that the limits of detection（LOD，S/N≥3） were in the range of 0.2-7.0 μg/L.The limits of quantitation（LOQ，S/N≥10） were in the ranges of 0.04-1.18 mg/kg for capsule and 0.007-0.235 mg/L for oral solution,respectively．The method validation was carried out by LOQ levels，and the recoveries were in the range of 31.0%-114.0% with relative standard deviations（RSDs） of 25%-149%．The screening of analytes was performed by precision mass matching and library searching.The retention time,isotopic abundance and multiple-stage ion mass spectra were employed for the confirmation.This method is simple,rapid,credible and sensitive,and could be applied in the simultaneous screening and identification for illegally added PDE-5 and analogues in health foods.Moreover,the ion fragmentation patterns of these drugs could be exploited to predict the chemical formulas and structures of the unknown derivatives and structural analogs of phosphodiestrase-5 inhibitors.关键词：health food;phosphodiestrase-5 inhibitor;analogue;screening;liquid chromatography-ion trap-time of flight tandem mass spectrometry（LC-MS-IT-TOF）
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发布时间： - 摘要：A comprehensive analytical method based on ultra performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry（UPLC-Q-TOF-MS） was developed for the rapid screening of 18 coumarin compounds（e.g.dihydrocoumarin,7-hydroxycoumarin,6-methoxy-7-hydroxycoumarin,6,7-dimethoxycoumarin,coumarin,7-methoxycoumarin,4-methyl-7-hydroxycoumarin,psoralen,8-methoxypsoralen,7-methylcoumarin,isopsoralen,5-methoxypsoralen,4-methyl-7-ethoxycoumarin,imperatorin,2′,4,8-trimethylpsoralen,8-hydroxypsoralen,isoimperatorin and cyclocumarol） in cosmetics.Various cosmetic samples,including cream,lotion,shampoo,powder and lipstick,were extracted under ultrasonication.The extract was centrifuged,and the upper solution was concentrated with rotary evaporator.The reconstructed solution was then cleaned up with Oasis HLB solid phase extraction cartridge.The screening analysis was carried out by atmospheric chemical ionization-quadrupole-time-of-flight mass spectrometry after the chromatographic separation on a Waters ACQUITY UPLC BEH C18（150 mm×2.1 mm,1.7 μm） column within 10 min.The limits of quantitation（LOQs） for 18 coumarin compounds ranged from 10 μg/kg to 60 μg/kg.The mean recoveries at three spiked levels ranged from 85.2% to 95.1%,with relative standard deviations of 3.2%-8.6%.The method is accurate,rapid and sensitive,and can provide a reliable and effective technique for the high-throughput screening of cosmetics.关键词：ultra performance liquid chromatography-quadruple time-of-flight mass spectrometry（UPLC-Q-TOF-MS）;cosmetics;coumarin compounds;rapid screening
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发布时间： - 摘要：An ultra performance liquid chromatography tandem quadrupole time-of-flight mass spectrometric method(UPLC/Q-TOF MS） was developed for rapid separation and identification of phospholipids in rat plasma.The classical Bligh-Dyer was used as extraction method.The target compounds were separated on a BEH C18 column by gradient elution using 10 mmol/L ammonium formater(A）-10 mmol/L ammonium formate acetonitrile/isopropanol(1∶1） (B） as mobile phase,and detected by MS under ESI+ and ESI- mode. 81 compounds were identified by UPLC/Q-TOF MS based on MS/MS fragment ions information,elemental composition in Masslynx 4.1 and the Lipid Maps database,among which 7 PE,7 PI and 1 SM were obtained,and the rest were all PC.The method was rapid，simple and credible for the identification of phospholipids in rat plasma,and could provide a foundation for the research of phospholipids metabonomics.关键词：UPLC/Q-TOF MS;plasma;phospholipids
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发布时间： - 摘要：Electrochemical behaviors of salbutamol on glassy carbon electrode modified by graphene/polymerized thionine were investigated by cyclic voltammetry and differential pulse voltammetric method.A good voltammetric response to salbutamol was obtained on the modified electrode.Under the conditions of pH 7.0，scan range of-0.6-0.4 V and scan rate of 80 mV/s,a good linear relationship between peak current and salbutamol concentration was obtained in the range of 3.1×10-7-8.5×10-5 mol/L,and the detection sensitivity could reach to 9.6×10-8 mol/L(S/N=3).The results showed that the graphene/polythionine modified electrode displayed excellent reproducibility and stability.关键词：graphene;thionine;salbutamol;electrochemical behavior
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发布时间： - 摘要：Using phoxim as template,α-methacrylic aid(MAA) as monomer,ethylene glycol dimethacrylate(EDMA) as cross-linker and 2,2-azobisisobutyronitrile(AIBN) as initiator,the phoxim molecular imprinted polymers(MIPs) was synthesized by polymerization in acetonitrile.MIPs were characterized by infrared spectroscopy and scanning electron microscopy.Scatchard plot analysis revealed that two kinds of different binding sites existed in MIPs,in which the maximum amounts of apparent binding and dissociation constants of binding sites were as follows:Qmax1=70.58 μmol/g,KD1=0.72 mmol/L;Qmax2=531.8 μmol/g,KD2=7.80 mmol/L.5 mg polyvinyl chloride(PVC) and 15 mg imprinted polymer were ultrasonically dispersed in 20 mL of tetrahydrofuran(THF),phoxim molecularly imprinted polymer modified electrode was prepared by adding 32 μL the dispersion dropwise onto the surface of glassy carbon electrode(GCE).Linear sweep voltammetry(LSV) was employed in the process of electrochemical measurements.The experimental results showed that the optimum acidity of 0.03 mol/L HCl-0.02 mol/L KCl solution is pH 2.2,and the optimum incubation time is 5 min.A highly linear response to phoxim in the concentration of 1.2×10-7-6.0×10-3 mol ?L-1 was observed,with a detection limit of 60×10-8 mol/L estimated at a signal-noise ratio of 3.The sensor was applied in the analysis of phoxim in real sample with recoveries of 93.8%-96.2%.The electrode modified with phoxim molecular imprinted polymer exhibited a good selectivity and sensitivity to phoxim when it was exposed to a series of closely related compounds with similar electrochemical characteristics,e.g.triazophos,chlorpyrifos and dimethoate.关键词：molecular imprinted polymer;phoxim;modified electrode
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发布时间： - 摘要：According to the special properties of functionalized ionic liquid modified graphene （IL-GR） and nano Au,IL-GR was firstly immobilized on the glass carbon electrode via chitosan （CHIT） cross linking,and then a layer of nano Au was adsorbed to form Au/IL-GR-CHIT composite film.Finally,acetylcholinesterase（AChE） was immobilized on the composite film by adsorption.A novel biosensor for detection of organophosphorus pesticides enzyme was developed,and used for the determination of trichlorfon.Different technologies were employed to study the construction process and the electrochemical properties of the biosensor.The results showed that the nanocomposite not only provided a biocompatible microenvironment to keep the bioactivity of AChE,but also exhibited a strong synergetic effect improving the sensing properties of biosensor.Linear relationship between inhibition percentage（A） and logarithm of concentration of trichlorfon was found in the range of 2.0×10-10 -1.0×10-6 mol/L,and the detection limit（S/N=3） was calculated to be 2.1×10-12 mol/L.The recoveries of trichlorfon in vegetable ranged from 97.5% to 107.2%.关键词：graphene;ionic liquid;nano-Au;acetylcholinesterase biosensor;trichlorfon
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发布时间： - 摘要：Lauryl methacrylate（LMA） was grafted on the surface of 5 μm silica by atom transfer radical polymerization（ATRP） using 2-bromoisobutyryl bromide as initiator and CuBr/2,2′-bipyridyl（Bpy） as catalytic system,and a novel Sil-LMA chromatographic stationary phase was obtained.The stationary phase was characterized by elementary analysis.Hydrophobic selectivity of the Sil-LMA was evaluated by using aromatic compounds as analytes and methanol-water as binary mobile phase.Effects of methanol content in the mobile phase and temperature on chromatographic property of the stationary phase were investigated.The chromatographic property of the stationary phase was evaluated using hydroxybenzene compounds and amine compounds as solutes,and parameters of kinetics and the thermodynamics were also determined.The amount of monomer was calculated to be 2.323 3 mg/m2 on the surface of silica.The results demonstrated that the stationary phase can effectively separate five hydroxybenzene compounds and five amine compounds in RPLC mode.Compared with that of C18 column under the same chromatographic conditions,the separation efficiency of the stationary phase was better,and the analysis time was shortened.The stationary phase possessed a good reversed-phase chromatographic behavior,which was found to be well consistent with reversed-phase retention mechanism.关键词：atom transfer radical polymerization;reversed phase liquid chromatography（RPLC）;hydroxybenzene and amine compounds;chromatographic property
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发布时间： - 摘要：In this paper,Concentration-Synchronous-Matrix-Fluorescence Spectroscopy(CSMF) was applied to characterize the chemical fingerprint information more comprehensively by adding concentration as a new dimension to fluorescence spectroscopy.Two tiered petroleum related sample sets(including the different spill oil types and different source crude oil sample set,and the closely-related source sample set with disturbance of weathering and seawater adulteration) were analyzed by principal component analysis(PCA).The results showed that for the crude oil samples from China,the weathering have no significant effect on the CSMF,and the PCA can classify the samples into different oil types in the principal components space according to the oil heaviness.Support Vector Machine(SVM),along with Leave-One-Out Cross-Validation,was used for confirmation of the validity of this method.100% accuracy was obtained for the different spill oil types and different source crude oil sample set,and 77% accuracy was for the closely related source sample set with disturbance of weathering and seawater adulteration.Detailed discussion indicated that pair-wise classification,can acquire higher accuracy than multi classification,and a tiered classification method from multi classification of different oil spill types to pair wise classification of closely related crude oil is then recommended for oil species identification.All the results suggested that the CSMF can be used as a rapid and reliable detection and characterization method for petroleum oil contaminants.关键词：concentration dependent synchronous fluorescence spectroscopy;concentration-synchronous-matrix-fluorescence spectroscopy(CSMF);oil spill fingerprinting;principal component analysis(PCA);support vector machine(SVM)
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发布时间： - 摘要：A new method using TurboFlow online cleanup(TFC) liquid chromatography combined with tandem mass spectrometry(MS/MS) was developed for the determination of carbendazin,imidacloprid,acetamiprid and thiophanate-methyl residues in vegetables and fruits.Samples were extracted with acetonitrile,and purified on a Cyclone-p column.The analytes were eluted from the extraction column and put into the analytical column(Betasil Phenyl-hexyl C18) prior to chromatographic separation and electrospray MS/MS detection.The calibration curves were linear in the range of 1-50 ng/mL with correlation coefficients more than 0.999 7.The limits of quantitation(LOQs) were 10 μg/kg.Average recoveries of the analytes at three spiked concentration levels ranged from 80.3% to 109.9%,with relative standard deviations of 1.5%-7.8%.关键词：TurboFlow on-line cleanup liquid chromatography-tandem mass spectrometry;carbendazin;imidacloprid;acetamiprid;thiophanate methyl;vegetables and fruits;pesticides residues
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发布时间： - 摘要：A new method was developed for the group analysis of toxaphene mixtures using a comprehensive two-dimensional gas chromatography coupled with micro electron-capture detector(GC×GC-μECD).Different polarity and selectivity columns,including DB-XLB,DB-1MS and BP-1,were used as first dimension and combined with columns of increasing polarity in the second dimension,i.e.BPX-50.An DB-1MS(20 m×0.25 mm×0.25 μm) combination with BPX-50(2 m×0.1 mm×0.1 μm) yielded highly structured chromatograms and revealed a complex mixture of 923 compounds.GC×GC-μECD parameters,including temperature programs,carrier gas flow rate and modulation period were also optimized.Toxaphene congeners were well separated with the optimized methods.The peak areas of all congeners of different chlorinated toxaphene were calculated.It is found that hepta ,octa and nona chlorinated compounds were the major components and contribute 85% of the total toxaphene mass.The matrix-matched external standard calibration curves were used for quantitative analysis.Linear range of this method were 10-500 μg/L and limit of detection were 0.2-0.6 μg/L of the different chlorinated toxaphene.The repeatability and reproducibility at a concentration of 10 μg/L evaluated with RSDs(n=7) of 9%-20%.It can be seen the use of comprehensive two-dimensional GC substantially improves the quality of toxaphene analysis compared to one-dimensional gas chromatography (1D-GC),hundreds congeners could be separated in toxaphene after a run which took less than 2 h.The results illustrate the potential of the GC×GC-μECD developed for the fast analysis of trace amount of complex compounds.关键词：comprehensive two-dimensional gas chromatography;different chlorinated toxaphene;electron capture detector;group separation
- 2009
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发布时间： - 摘要：A homemade desktop atmospheric pressure ionization time-of-flight mass spectrometer was developed,which presented an orthogonal-injection construction consisting of an ionization,an atmosphere-vacuum interface,the area of transmission and mass spectrometer whose length is 550 millimeter.Instrumental performance characteristics were obtained with the electrospray ionization.The mass analyzer provided mass resolving power of 4 200,4 900,6 000 and 7 500 at m/z 38.96,132.91,609.28 and 1 009.58,respectively.Methanol and PEG1500 ion peaks, ［CH3OH+H］+ and ［HO（CH2CH2O）39H+Na］+ were presented with m/z value of 33 and 1 758,respectively.A calibration curve was established by plotting peak area of reserpine at m/z 609 with the sample concentration in the range of 1-200 pg/μL.The detection limit（S/N=3） of the method was 1 pg/μL.As an atmospheric pressure ionization interface,the molecule ion reactor leads to ion decomposition and can be used to investigate the molecular structure.Combined with atmospheric pressure ionization,this instrument is applicable in the fields of pharmaceutical analysis,environmental analysis and food analysis,etc.关键词：electrospray ionization;atmosphere-vacuum interface;time-of-flight spectrometer;collision-induced dissociation
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发布时间： - 摘要：Prussian blue and chitosan（PB-CS） composite film was prepared by potentiostatic deposition.Core/shell structure nano-TiO2@Pt composite was prepared and deposited on the surface of PB-CS composite film,which was utilized to immobilize glucose oxidase（GOD）.nano-TiO2@Pt composite could obviously improve electrical conductivity of biosensor and amount of immobilized GOx.Furthermore,CS can effectively protect PB from leaking out,which could increase the catalytic activity of this biosensor.This novel glucose biosensor shows a good linear relationship with glucose concentration in the range of 1.2×10-6-1.1×10-3 mol?L-1 with a correlation coefficient（r） of 0.998 6.The limit of detection is 4.0×10-7 mol?L-1 and the sensitivity is 13.31 mA?mol?L-1?cm-2.The relative standard deviation for the method was 3.8% at concentration level of 0.3 mmol?L-1 glucose standard solution for 5 determinations.关键词：Prussian blue（PB）;chitosan（CS）;nano-TiO2@Pt composite;glucose oxidase（GOD）
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发布时间： - 摘要：A poly L-leucine（L-LEU） modified single-walled carbon nanotube/glass carbon electrode（SWCNT/GCE） was fabricated by electrochemical polymerization method.The electrochemical behaviors of hydroquinone（HQ） and catechol（CC） on the modified electrode（poly L-LEU/SWCNT/GCE） were investigated by cyclic voltammetry（CV）,differential pulse voltammetry（DPV） and electrochemical impedance spectroscopy（EIS）.The experimental results suggested that poly L-LEU/SWCNT/GCE exhibited an obvious electrocatalytic activity and electroseparation.The redox responses of HQ and CC increased significantly,the differences of peak potential of oxidation and reduction were 124 mV and 131 mV,respectively.The linear response ranges for HQ and CC were 2.0×10-7-1.0×10-4 mol/L and 5.0×10-7-1.0×10-4 mol/L,with detection limits of 8.0×10-8 mol/L and 1.0×10-7 mol/L,respectively.The modified electrode showed a good repeatability and stability.The proposed method was applied in the determination of HQ and CC in simulated water samples with satisfactory results.关键词：single-walled carbon nanotube;poly L-leucine;modified electrode;hydroquinone(HQ);catechol(CC)
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发布时间： - 摘要：An analytical method was developed for the determination of contents of maleic acid (maleic anhydride) and fumaric acid in starch and related foods by high performance liquid chromatography(HPLC).The samples were extracted with 1% ammonia water-methanol solution(1∶1).The target compounds were separated on an Atlantis-T3 C18 column using 0.03 mol/L ammonium dihydrogen phosphate solution as mobile phase,and detected with diode-array detector.Under the optimized conditions.Two compounds were separated completely.The average spiked recoveries were in the range of 82.5%-103.5% with RSDs less than 4.3%.The limits of quantitation(LOQs) for maleic acid and fumaric acid were both 2.0 mg/kg.With the advantages of convenience,sensitivity,good recoveries and repeatability,the method was suitable for the detection of maleic acid(maleic anhydride) and fumaric acid in starch and related foods.关键词：maleic anhydride;maleic acid;fumaric acid;high performance liquid chromatography(HPLC);starch;related foods
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发布时间： - 摘要：A method was developed for the simultaneous determining of five phenolic compounds，including biphenol A（BPA）,octylphenol（OP）,nonylphenol（NP）,octyl phenoxypoly（ethyleneoxy）ethanol（OPEO） and nonylphenoxypoly（ethyleneoxy）ethanol（NPEO）） in waterborne coatings by QuEChERS/ultra high performance liquid chromatography with fluorescence detector（UPLC/FLD）.Samples were dispersed firstly by QuEChERS（PSA+C18+MgSO4）,and stirred uniformly to reduce the impurity,then extracted ultrasonically with dichloromethane-acetonitrile（1∶3）.The ultimate solution was quantified by UPLC/FLD on a C18 column by gradient elution with water-acetonitrile as mobile phase at a flow rate of 0.2 mL/min.Under the optimized conditions,the method had good linear relationships（r＞0.999 5） in the range of 5-1 300 μg/L for five compounds.The method detection limits(MLOD) for targeted compounds ranged from 0.4 mg/kg to 1.0 mg/kg.The spiked recoveries of five compounds varied from 97.5% to 114% with relative standard deviations（RSDs） of 2.6%-6.5%.The results showed that the method was simple,sensitive and precise,and could meet the qualification and quantification analysis requirements for BPA,OP,NP,OPEO and NPEO residues in waterborne coatings.关键词：UPLC;QuEChERS;waterborne coatings;phenolic compounds
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发布时间： - 摘要：A method was established for the determination of alkaloids in tobacco by gas chromatography-triple quardrupole mass spectrometry（GC-MS/MS）．The samples were extracted by 10% NaOH and CH2Cl2，then determined by GC-MS/MS in multi-reaction monitoring（MRM） mode，and internal standard method was applied to quantify alkaloids．The average recoveries of alkaloids in tobacco samples were in the range of 93.2%-99.0% with relative standard deviations of 2.8%-6.7%.The method was simple,rapid and sensitive,and was suitable for the analysis of alkaloids in tobacco.关键词：gas chromatography-triple quardrupole mass spectrometry;multi-reaction monitoring（MRM）;tobacco;alkaliods
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发布时间： - 摘要：A dynamic coating capillary electrophoresis method with cation exchange chromatography was developed for the determination of bovine lactoferrin（bLF） in milk．The bLF was isolated from milk by using purolite C115-E cation exchange resin,and then quantitatively analyzed in the capillary coated by quaternized celluloses（QC）.Effects of QC concentrations and pH values of the running buffer on the separation of bLF by capillary electrophoresis were investigated.It was shown that the use of QC coating in CE could drastically reduce the adsorption of bLF on the inner surface of fused silica capillary.QC can not only cover the silanol groups on the capillary inner surface,but also repel the basic proteins electrostatically to prevent bLF protein adsorption.After the optimization of analytical conditions,calibration with bLF protein was carried out and linear regression data were presented.Furthermore,the influences of extraction conditions such as incubation time on the extraction efficiencies of bLF were also investigated.The recoveries of bLF in milk at three spiked levels ranged from 87% to 112% with relative standard deviations（RSDs） of 4.4%-12.1%.This method had the advantages of rapidness,high efficiency,low sample and reagent consumption,and was suitable for the determination of bLF in milk.关键词：cation exchange chromatography;capillary electrophoresis;dynamic coating;bovine lactoferrin（bLF）
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发布时间： - 摘要：Based on the theories of heteronuclear single quantum coherence(HSQC) and heteronuclear multiple-quantum coherence(HMQC),1D-nonselective-1H-31P HSQC,heteronuclear single quantum coherence and multiple-bond correlation(HSQMBC)were applied and 1D nonselective 1H-31P HMQC pulse sequences were designed for screening the organophosphorous(OP) compounds.The differences among these methods were studied,especially in peak shape and sensitivity.From results of the analysis on the OP compounds in the OPCW proficiency test,1D nonselective HMQC method has been proved to be the most effective and sensitive in NMR experiments so far.关键词：1H-31P heteronuclear coherence;NMR;organophosphorous compounds
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发布时间： - 摘要：A simple method based on microwave extraction coupled with gas chromatography-mass spectrometry was developed for the determination of trace amounts of phthalates esters（PAEs） in environmental particle matter（PM2.5）.The sample was extracted with ethyl acetate-acetone mixed solvent by microwave-assisted extraction.The PAEs were separated on a DB-5MS column and detected by MS under SCAN/SIM mode.The external standard method was used for the quantification.The linear ranges for the calibration curves of PAEs ranged from 100 pg to 1 000 pg.The limits of detection（MDL） ranged from 0.101 ng/m3 to 0.262 ng/m3.The spiked recoveries were in the range of 81.6%-129%.The particle matters of ambient air in the Changzhou chemical industry park were successfully analyzed using the proposed method.15 PAEs were detected in the sample.The concentrations of diisobutyl phthalate（DIBP）,dibutyl phthalate（DBP）,dioctyl phthalate（DEHP） were high.The results showed that this would be a valuable method for the PAEs analysis in particle matter of ambient air.关键词：microwave-assisted extraction;gas chromatography-mass spectrometry（GC-MS）;phthalate esters（PAEs）;particle matter（PM2.5）
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发布时间： - 摘要：Transition metals in highest oxidation state complexes have been considerably used in the analysis of several organic compounds and initiator of graft copolymerization.In this work,it is found that some transition metals in highest oxidation state complexes,for example,dihydroxydiperiodatocuprate(DPC）,dihydroxydiperiodatonickelate(DPN） and dihydroxydiperiodatoargentate(DPA）,are good oxidants which can react with luminol to emit chemiluminescence(CL） in alkaline mediums.The CL intensity could be greatly sensitized by some aminoglycoside antibiotics.The application of the CL system was studied by using luminol-DPC-tobramycin as a model，and a new CL method for the determination of tobramycin in human serum was proposed by combining with the flow injection technology.Effect of reagents concentration on CL intensity was investigated.Under the optimum experimental conditions,the CL intensity was proportional to tobramycin concentration over the range of 6.0×10-8 – 2.0×10-6 g/mL with a detection limit(3σ） of 1.5×10-8 g/mL.The proposed method had a good reproducibility for 5.0×10-7 g/mL tobramycin with relative standard deviation(RSD,n=7） of 2.7%.It was successfully applied in the determination of tobramycin in human serum.关键词：luminol;transition metals in highest oxidation state complex;chemiluminescence;aminoglycoside antibiotics;tobramycin
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发布时间： - 摘要：A method regarding determination of ethoxyquin residue in fruits was presented by liquid chromatography with inhibited oxidation reactionAnother antioxidant was added in order to inhibit the oxidation reaction of ethoxyquin.In this experiment，the samples were added with vitamin C,homogenized,then extracted with hexane,concentrated to dryness and redissolved in acetonitrile.The target compound was separated on a C18 column using acetonitrile-water as mobile phase,and detected by HPLC.The quantitation limits for ethoxyquin in apple and pear were both 0.05 mg/kg.The spiked recoveries were in the range of 79.4%-108% with relative standard deviations of 3.8%-9.3%.The developed method was suitable for the determination of ethoxyquin in apple and pear samples.关键词：fruit;ethoxyquin;inhibited oxidation;vitamin C
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发布时间： - 摘要：The related substances in Entecavir Oral Preparation were separated on a Thermo C18 column（150 mm×2.1 mm×2 μm） by gradient elution，with methanol-0.2%formic acid as mobile phase at a flow rate of 0.3 mL/min and a column temperature of 30 ℃，and the detection wavelength was set at 254 nm.The proposed method was used to detect the related substances in Entecavir Oral Preparations from different pharmaceutical manufacturers.The chemical structures of related substances were analyzed by LC-MS/MS.Two structures of the related primary substances were identified，which both belonged to the isomers of entecavir.This study provided an important basis for the quality and stability control of this product.关键词：entecavir;related substances;LC-MS/MS
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