最新刊期
卷 34 ， 期 11 ， 2015
- 摘要：A rapid,sensitive and accurate method for the simultaneous determination of 5 kinds of chlorophenols(CPs) in seawater samples by dispersive magnetic solid phase extraction-liquid chromatography(dMSPE-HPLC) was developed.The seawater samples were firstly enriched with pentachlorophenol-imprinted amino-functionalized nano-Fe3O4-polymer magnetic composite material(nFe3O4@MIPNH2-polymer),then separated on a C8 analytic column(250 mm×4.6 mm×5.0 μm) using methanol-NH4Ac solution(70∶30) as mobile phase and detected at 230 nm via UV detector.The results showed that under the optimal condition,the calibration curves were linear in the range of 1-5000 ng/L with correlation coefficients(r2) higher than 0.9989 for target chlorophenols.The spiked recoveries were between 86.5% and 98.8% with relative standard deviations(RSDs) of 0.8%-8.6%.The limits of detection(LODs) were in the range of 0.18-1.20 ng/L and the limits of quantitation(LOQs) were between 0.6 ng/L and 4.0 ng/L.The developed method could be applied in the routine analysis of chlorophenols in seawater samples.关键词：amino-functionalized;molecular-imprinted magnetic material;chlorophenols;seawater;dispersive solid phase extraction(dMSPE)
- 2320
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- 1188
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- 10
发布时间： - 摘要：Different concentrations（0-9%） of inorganic salts,such as NaCl，MgSO4，NaOH,were added into the ethanol-water system,and principal component analysis（PCA） was used to analyze the LF-NMR（T2） relaxation characteristics of the samples.The results indicated that the type and concentration of the inorganic salts could change the relaxation characteristics of the ethanol-water system.For the inorganic salt-water system,there was only one relaxation peak,and the relaxation time followed the order like this,MgSO4>NaOH>NaCl.When the inorganic salt was added into the water-ethanol system,two relaxation peaks appeared on the map,and the relaxation peaks of NaCl/NaOH-ethanol-water system appeared at 200-330 ms and 1300-1600 ms,while that of MgSO4-ethanol-water system located about 250-335 ms and 1620-1707 ms.After principal component analysis on the LF-NMR data,good differentiations among inorganic salt,water system and ethanol-water system could be found.And the distribution of samples moved regularly on the principal component scores with the increase of concentration.Therefore,the LF-NMR relaxation characteristics could be used to reflect the interaction of inorganic salt in water and ethanol-water systems with the aid of PCA.关键词：LF-NMR;inorganic salt;ethanol-water system;relaxation characteristics
- 1869
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- 1248
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- 0
发布时间： - 摘要：A method of HPLC-quadrupole/electrostatic field orbitrap HRMS（HPLC-QE HRMS）was established to analyze 10 polyphenols in wine with the help of qualitative confirmation of HRMS.The samples were extracted with ethyl acetate after acidized.The qualitative confirmation was carried out by full scan and target MS2 spectra after separation on an ACQUITY UPLC BEH C18 column（2.1 mm×100 mm,1.7 μm）.An external standard method was used for quantitative analysis.The limits of quantitation（LOQs） of 10 polyphenols ranged from 0.0005 mg/L to 0.0025 mg/L.The spiked recoveries were between 82.0% and 109.1% with RSDs less than 10%.关键词：high performance liquid chromatography（HPLC）;high resolution mass spectrometry;polyphenols;wine
- 2037
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- 974
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- 4
发布时间： -
Spectroscopic Studies and Molecular Docking of the Interaction between Myricetin and Calf Thymus DNA
摘要：The interaction between myricetin and calf thymus DNA（ct-DNA） at physiologic pH was investigated by ultraviolet and fluorescence spectroscopy in conjunction with fluorescent probe methylene blue（MB）,circular dichroism（CD） and molecular modeling methods.Thermodynamic parameters（ΔH<0 and ΔS<0） indicated that hydrogen bond and van der Waals play main roles in the binding of myricetin to ct-DNA.The results of spectroscopic experiments suggested that the intrinsic fluorescence of myricetin was quenched in the presence of ct-DNA by static quenching mechanism.The binding constant and the corresponding number of binding sites（n） were calculated to be 1.86×103 mol-1 and 1,respectively.In competition experiments,myricetin was unable to replace MB（an intercalator） from MB-DNA complex,which is indicative of groove binding.Circular dichroism spectra of DNA showed that the attendance of myricetin was not able to change the formation of DNA,which is in agreement with groove binding mode of interaction.Moreover,from molecular modeling methods,a docked structure with minimum energy was obtained,in which myricetin was located in minor grooves preferentially surrounding with A and T rich regions.The results of docking showed that 7-O in A ring and 3’-O in B ring of myricetin were bound with DA18 and DA6 of DNA double helix by hydrogen,respectively.The binding distances were 2.061 ? and 1.918 ?,respectively.关键词：myricetin;calf thymus DNA（ct-DNA）;groove binding;spectroscopy;molecular modeling- 1864
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- 825
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- 1
发布时间： - 摘要：In order to investigate the migration of aromatic amines from different paper packaging materials into foods,a solvent extraction/gas chromatography-mass spectrometric（GC-MS） method was developed for the detection of aromatic amines in paper packaging materials and food simulants,using modified polyphenylene oxide（Tenax） as food simulant.The pretreatment method of sample and GC-MS condition were studied.The paper packaging material sample was extracted by ultrasonic extraction for 30 min using 10 mL tert-butyl methyl ether as solvent.The Tenax sample was extracted by ultrasonic extraction for 15 min using 10 mL n-hexane as solvent.The extract was separated with a DB-17 capillary column under selected ion monitoring（SIM） mode.The targets were quantitatively analyzed by the internal standard method using naphthalene-d8,2,4,5-trichloroaniline and anthracene-d10 as three internal standards for the corresponding aromatic amines.The calibration curves of 20 aromatic amines were linear in the range of 0.001 4-0.14 mg/dm2,with correlation coefficients（r） greater than 0.998 and detection limits of 0.000 1-0.000 3 mg/dm2.The relative standard deviations（RSD） ranged from 1.9% to 6.9%,and the recoveries were in the range of 80.6%-107.2% for both paper packaging material sample and Tenax.The method was applied in analysis of the migration of aromatic amines in two types of paper packaging materials.The results indicated that the small molecular weight and low boiling point aromatic amines had a certain degree of migration under the investigated conditions.The method was simple,quick,sensitive and reproducible,and could meet the requirement for the determination of the migration of aromatic amines in paper packaging materials.关键词：aromatic amine;migration;simulant;Tenax;paper packaging materials;gas chromatography-mass spectrometry
- 1924
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- 928
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- 4
发布时间： - 摘要：A new magnetic affinity immunoassay（MAIA） method based on gold-magnetic particle and HRP-conjugated phage antibody was developed.Gold-magnetic particle were coated with staphylococcus protein A（SPA） and coupled with polyclonal antibody（pcAb） to construct functionalized capturing probes,and HRP-conjugated phage antibody was then used as specific detecting probe to design MAIA for trace detection of abrin.The calibration curve was linear（r=0.991 0） in the range of 0.008-250 μg/L,with a limit of detection（LOD） of 0.008 μg/L,and a limit of quantitation（LOQ） of 0.008 μg/L.Integrating the unique advantages of functionalized SPA gold-magnetic particle probe and HRP-conjugated phage antibody with its high sensitivity,specificity and anti-interference,the method is proven to be well suited for the analysis of trace abrin in various environmental samples.关键词：gold-magnetic particle;functionalized probe;HRP-conjugated phage antibody;abrin;detection
- 1827
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- 891
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- 0
发布时间： - 摘要：In this paper,SiO2-coated carbon nanotubes（CNTs/SiO2） were synthesized by sol-gel technique.The vinyl groups were introduced onto the surface of CNTs/SiO2 through chemical modification with γ-methacryloxypropyl trimethoxysilane（MAPS）.Through free radical polymerization,CNTs/SiO2-MIPs were successfully obtained by the copolymerization in presence of MAPS-CNTs/SiO2 as support,rutin as template molecule,acrylamide as functional monomer and ethylene glycol dimethacrylate as crosslinker.CNTs/SiO2-MIPs were characterized by infrared spectrometry,thermal gravimetric analysis and scanning electronic microscopy.CNTs/SiO2-MIPs were coated onto glassy carbon electrode to construct an electrochemical sensor.The electrochemical characteristics of CNTs/SiO2-MIPs modified electrode were investigated by cyclic voltammetry and differential pulse voltammetry.The results showed that CNTs/SiO2-MIPs had a good specific adsorption property.DPV peak current response of CNTs/SiO2-MIPs sensor was nearly 2.84 times that of the non-imprinted polymers.In addition,the CNTs/SiO2-MIPs sensor could recognize rutin from its relatively similar molecules of quercetin,naringenin and ascorbic acid.The CNTs/SiO2-MIPs sensor had a wide linear range over rutin concentration range of 0.1-100.0 μmol/L with a detection limit（S/N=3） of 0.032 μmol/L.The CNTs/SiO2-MIPs imprinted sensor was successfully used for the determination of rutin in tablets.关键词：CNTs/SiO2;surface imprinting;rutin;electrochemical sensor
- 2405
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- 1146
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- 7
发布时间： - 摘要：Low-abundance proteome of chicken egg white were studied by using combinatorial peptide ligand libraries(CPLL) and the linear ion trap quadrupole(LTQ) mass spectrometry.The effect of salt concentration and elution order on the enrichment efficiency of CPLL was investigated.The results showed that the higher salt concentration，the stronger interaction between the egg white protein solutions，which effected CPLL enrichment efficiency significantly.The lysozyme could be separated effectively in the order of urea CHAPS(3-［3-cholamidopropyldimethylammonio］-1-propansulfonate) elution first ，HOS(hydro-organic solution) the second elution.High effective enrichmental conditions of CPLL were chicken egg white with 150 mmol/L NaCl,25 mmol/L KH2PO4，pH 8.8，urea CHAPS elution.Through the analysis of the SDS-PAGE band difference with 60 μg protein loaded after CPLL enrichment，45 species of low abundance proteins from chicken egg white were identified by LTQ mass spectrometry，of which two species were not reported yet.The result of subcellular localization analysis showed that egg white protein secreted protein was 19 species，which was in the majority.The number of unknown subcellular location of proteins from chicken egg white was taken the second placeThis paper shows that the CPLL technology is rapid，simple and sensitive，and is suitable for the determination and confirmation of the low-abundance protein in chicken egg white，that the depth of which reach the sub cellular level.关键词：chicken egg white;combinatorial peptide ligand libraries(CPLL);low abundance proteins;linear ion trap quadrupole(LTQ)
- 1880
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- 1025
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- 1
发布时间： - 摘要：A reflective surface plasmon resonance（SPR） optical fiber sensor based on silver mirror reaction was developed,and a quick surface biological functionalization on the silver nanofilm was realized by dopamine self polymerization for monitoring of antigen-antibody interaction.A homemade SPR instrument was applied to investigate the effect of sensing length and various modification on the SPR signals.In order to enhance the sensitivity of the SPR optical sensor,the length of the sensing area was optimized.As the length of the sensing area increased,the sensitivity based on wavelength shift showed an obvious increase,while the sensitivity based on reflectivity shift did not have a distinctive change.The results showed that the fabricated SPR optical fiber sensor has a high sensitivity.When the sensing length is 1.5 cm,the sensitivity based on wavelength shift is 4 166 nm/RIU,while the sensitivity based on reflectivity shift is 99%/RIU.In addition,the SPR optical fiber sensors were further modified with antigen,and used to monitor the process of IgG antigen binding on biosensors.Significant wavelength shifts were found after every surface modification step,which indicated that dopamine modification to realize quick surface biological functionalization on silver nanofilm was feasible and the further biological functionalization was successful.By monitoring the binding process of IgG antigen and IgG antibody,a gradual red shift of the wavelength was found during the binding process,demonstrating the potential biological application of this biosensor.关键词：optical fiber;surface plasmon resonance（SPR）;silver mirror reaction;biosensors;interaction
- 1915
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- 902
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- 1
发布时间： - 摘要：Based on reaction of o-phthalaldehyde（OPA）-NH3-sulfite system,a solid-phase fluorescence spectrometric method was established for the determination of ammonia nitrogen in natural water sample using filter paper as solid support.Experimental parameters such as soaked time of the filter paper,pH value and reaction time were optimized.The optimal conditions were as follows:soaked time of filter paper:＞4 h;pH value:11.5-13.0;reaction equilibrium time:165 min.Under the optimized experimental conditions,the calibration curve was linear in the range of 2.00-12.0 μmol/L,with a detection limit of 0.746 μmol/L.The spiked recoveries were in the range of 89.6%-101.6% for spring water and river water.The proposed method was applied in the detection of ammonia nitrogen in fourteen river water samples,and the results were consistent with those obtained from the indophenol blue method.关键词：ammonia nitrogen;o-phthalaldehyde;fluorescence;solid-phase
- 2074
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- 844
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- 3
发布时间： - 摘要：A rapid method was developed for the determination of ethylenethiourea（ETU）residues in fruits by ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）under multiple reaction monitoring mode.The samples were extracted with alkaline acetonitrile containing 1.5% NH3?H2O,cleaned-up by adding Florisil,separated on an HSS T3 column using acetonitrile-0.2% formic acid as mobile phase by gradient elution at a flow rate of 0.4 mL/min,and confirmed by positive electrospray ionization tandem mass spectrometry under multiple reaction monitoring（MRM）mode.The detection was quantified by the external standard method.The results indicated that the calibration curves of ETU were linear in the range of 5-200 μg/L with correlation coefficients more than 0.999.The average recoveries of ETU in five fruit samples at three spiked levels of 5,20,50 μg/L were in the ranges of 93.6%-101.4%（apple）,91.2%-98.4%（peach）,84.6%-95.1%（grape）,86.8%-97.9%（citrus）,and 79.5%-96.3%（banana）,respectively.The limits of detection（LOD）for these five fruits were 0.08,0.13,0.11,0.23,0.26 μg/L,and the limits of quantitation（LOQ）were 0.28,0.42,0.37,0.75,0.86 μg/L,respectively.The method is simple,accurate,economic and friendly to the environment,and could meet the requirements for rapid determination of ETU residues in fruits.关键词：fruits;ethylenethiourea（ETU）;residues;ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）
- 1922
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- 979
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- 6
发布时间： - 摘要：A novel adsorbent material,triethylenetetramine modified β-cyclodextrin crosslinked resins（TETA-β-CDP）was synthesized,and the synthesized material was characterized by Fourier transform infrared spectrometry（FT-IR）.The conditions of adsorption and desorption of the adsorbent material for Pb2+ and Cd2+ were optimized，and a new method was developed for the determination of trace lead and cadmium in rice by atomic absorption spectroscopy.It was found that,in the conditions of pH 5.5 and flow rate of sample solution of 1.0 mL/min,the lead and cadmium could be quantitatively preconcentrated on TETA-β-CDP separation resin with adsorption capacities of 22.8 mg/g and 31.3 mg/g,respectively.The adsorbed lead and cadmium could be eluted with 0.1 mol/L HCl at a flow rate of 0.8 mL/min.Under the optimum conditions,the calibration curves were linear over Pb2+ and Cd2+ concentrations in the ranges of 0.2-20 mg/L and 0.05-2.5 mg/L,with detection limits（3σ,n=11）of 0.038 mg/L and 0.016 mg/L,respectively.The relative standard deviations（RSDs）for the determination of 0.5 mg/L Cd2+ and 5 mg/L Pb2+ were 1.7%and 2.8%,respectively.The spiked recoveries of lead and cadmium were in the ranges of 97.5%-101.0%and 95.0%-102.5%,respectively.The method was applied in the determination of trace lead and cadmium in rice samples with satisfactory results.关键词：β-cyclodextrin（β-CD）;separation and preconcentration;flame atomic absorption spectrometry(FAAS);rice;lead;cadmium
- 1901
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- 1281
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- 1
发布时间： - 摘要：Preparation of a silica based sulfonated hypercrosslinked polystyrene-divinylbenzene strong cation exchanger was reported.Silica beads of an average particle size of approximately 5 μm were first reacted with divinyltetramethyl disiloxane to prepare the vinylated silica phase.The vinylated silica phase was then copolymerized with a monomer mixture of styrene-divinylbenzene(2∶1),and the hypercrosslinked polystyrene-divinylbenzene(HCL PS-DVB)derivated silica phase was prepared.And at last,the HCL PS-DVB silica phase was sulfonated to prepare the cation exchanger in an ice water bath.The strong cation-exchanger was characterized using infrared spectra.The cation-exchanger was proved to be stable in extreme acidic and in extreme basic solutions.The strong cation-exchanger was applied in the separation of basic organics with a good separation result.关键词：polystyrene-divinylbenzene;hypercross linked polymer;strong cation exchanger;ion chromatography
- 1927
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- 1265
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- 2
发布时间： - 摘要：An ultra-high performance liquid chromatographic（UPLC）method for the simultaneous determination of furfural,5-hydroxymethylfurfural and 5-methylfurfural in cigarette fragrances was established.After dilution,vibration and filtration,the cigarette additives were separated on a C18（2.1 mm i.d.× 100 mm,1.7 μm） column under isocratic elution mode using acetonitrile-water（10∶90） as mobile phase at a flow rate of 0.3 mL/min.The quantification of these analytes was achieved by the external standard method with a diode-array detector at 280 nm.Baseline separation of these analytes was achieved within 5.0 min.The linear ranges for 5-hydroxymethylfurfural,furfural and 5-methylfurfural were in the ranges of 0.004 2-40.00 mg/kg,0.004 6-30.00 mg/kg,0.006 9-30.00 mg/kg,with correlation coefficients（r2） of 0.999 2,0.999 9 and 0.999 8,respectively.The detection limits（S/N=3） for three analytes were 1.24,1.37,2.06 μg/kg,respectively.Relative standard deviations（RSD,n=11） were in the range of 0.1%-0.4%.The recoveries at spiked concentration of 0.005 0-10.18 mg/kg were 91.7%-106.0%.The proposed method has the merits of easy operation,fast analysis and accurate results,and is suitable for the simultaneous determination of 5-hydroxymethylfurfural,furfural and 5-methylfurfural in cigarette fragrances.关键词：ultra-high performance liquid chromatography（UPLC）;cigarette fragrances;furfural;5-hydroxymethylfurfural;5-methylfurfural
- 1965
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- 3
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- 1
发布时间： - 摘要：A method was developed for the determination of N，Na，Mg，P，Cl，K，Ca in milk powder by wavelength dispersive X-ray fluorescence spectrometric method with pressed powder pellets.Effects of experimental conditions，including X-ray tube Beryllium window thickness，current intensity of instrument，measurement time，and sample preparation，on the determination of nitrogen were studied.Different kinds of milk powder samples were chosen and determined firstly by reference methods，then calibration curves were drawn using both the milk powder samples with known contents and reference materials.To eliminate the effect，the theoretical α influence coefficient method was used to correct matrix effects.It was found that manual grinding could better realize the homogeneous treatment of the sample.Thickness of beryllium window was the main factor restricting the nitrogen determination，but influence of the current intensity of fluorescence intensity was limited.X-ray irradiation could cause milk powder browning，forming the color and smell similar to that of maillard reaction.Furthermore，internal protein also suffered severe damage，and multiple interference could make the contents of P，Cl，K，Ca change according to a certain rule.For nitrogen，limit of detection and RSD（n=9） were 900 mg/kg，29%，respectively，and for other elements，limits of detection and RSDs were less than 10 mg/kg，3.0%，respectively.The measurement results were consistent with the reference method.关键词：milk powder;nitrogen;X-ray fluorescence spectrometry;Maillard reaction
- 1827
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- 945
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- 1
发布时间： - 摘要：Two analytical methods for the detection of iodinated trihalomethanes(I-THMs) in drinking water by purge and trap(P&T) with gas chromatography-mass spectrometry(GC-MS) and liquid-liquid extraction with gas chromatography-electron capture detection(LLE-GC/ECD) were compared.The results showed that the LLE-GC/ECD method using methyl tert-butyl ether(MTBE) as extractant was more suitable for the qualitative and quantitative analysis of I-THMs.The linearity was observed in the range of 0.5-1 000 μg/L for 6 I-THMs quantified by internal standard,with correlation coefficients(r2) more than 0.99.The developed LLE-GC/ECD method showed a good repeatability with relative standard deviations(RSD,n=7)of 3.9%-6.4%.The limits of detection(LODs) were between 0.05 μg/L and 0.11 μg/L.Recoveries of I-THMs in surface water filtered source water,and tap water at spiked levels of 0.5,2.0,10.0 μg/L were in the range of 81.2%-108.6%,with RSDs of 2.6%-7.7%.The method was simple,rapid and sensitive,and could be well suited for the determination of I-THMs in drinking water.关键词：liquid-liquid extraction;gas chromatography-electron capture detector(GC-ECD);iodo-trihalomethane;drinking water
- 2095
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- 963
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- 3
发布时间： - 摘要：In this paper,cefepime was found to enhance the chemiluminescence(CL)of the luminol-potassium ferricyanide reaction system in alkaline condition.According to this fact,a flow injection chemiluminescence enhencement method for the determination of cefepime was developed.Under the optimum conditions,the linear range for cefepime was 3.0×10-6-4.0×10-5 g/mL,and the limit of detection was 2.8×10-6 g/mL.The relative standard deviation(RSD,n=11) was 1.5%for the determination of 2.0×10-5 g/mL cefepime.The method was applied in the determination of cefepime injection with satisfactory results.关键词：chemiluminescence enhencement;flow injection;cefepime;luminol;potassium ferricyanide
- 2034
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- 1158
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- 1
发布时间： - 摘要：A liquid chromatography-tandem mass spectrometric(LC-MS/MS)method was developed for the simultaneous determination of six pyrazole fungicides,including penflufen,fluxapyroxad,isopyrazam,furametpyr,bixafen and rabenzazole in grape wine samples.The sample was diluted with ultrapure water,and then cleaned up by HLB solid phase extraction.The separation was performed on an Agilent ZOBRAX C18 column(2.1 mm×150 mm,5 μm)using a gradient elution program with a mobile phase of 0.1%acetic acid-acetonitrile.The analyte was determined by electrospray ionization tandem mass spectrometry in multiple reaction monitoring(MRM)mode,and quantified by the external standard method.The results indicated that the calibration curves for pyrazole fungicides were linear(r2≥0999 3) in the range of 1.0-50.0 μg?L-1.The limits of quantitation(LOQs) were in the range of 0.1-0.4 μg?kg-1.The average recoveries at three spiked levels ranged from 72.8%to 92.6%with RSDs not more than 6.7%.This method is simple,rapid and sensitive,and is suitable for the analysis of six pyrazole fungicides in grape wines sample.关键词：grape wine;pyrazole fungicides;solid phase extraction(SPE);liquid chromatography-tandem mass spectrometry(LC-MS/MS)
- 1865
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- 924
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- 3
发布时间： - 摘要：The residue of organophosphorus pesticide(OPPs)is one of the most serious problems of food safety in China.It is urgently necessary to determinate the OPPs in foods.However,foods are a kind of complex matrix,and the OPPs must be extracted and purified by pretreatment method.In this work,the novel pretreatment methods of OPPs for instrumental analysis,including solid phase extraction,liquid-liquid microextraction,ultrasonic extraction,microwave assisted extraction,immune chromatography and enrichment by nano-materials etc,were introduced.The principles,advantages,disadvantages and the applications of these methods were introduced.This review provides a reference for related research projects.关键词：organophosphorus pesticides;pretreatment methods;food;review
- 2107
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- 1041
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- 3
发布时间： - 摘要：Drug screening is to apply the appropriate screening methods and screening technologies to extract the pharmacological active compounds from vast amounts of compounds.Drug screening is the key to improve the drug research efficiency,accelerate research cycle,cut down research cost and reduce investment risk,which makes the new drug research and development can be sustained.Drug screening new technologies have also become the important content of pharmaceutical research.More and more drug screening technologies have been developed,such as high throughput screening technology,high content screening technology,surface plasmon resonance technology and microfluidic chip technology,etc.These new drug screening technologies and their application are reviewed in this article.关键词：drug screening;high throughput screening;high content screening;surface plasmon resonance（SPR）;microfluidic chip
- 2165
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- 922
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- 3
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