最新刊期
卷 36 ， 期 3 ， 2017
- 摘要：A method was developed for the determination of Nε-（carboxymethyl）lysine（CML） and Nε-（carboxyethyl）lysine（CEL） in baking food using ultra performance liquid chromatography-quadrupole Time-of-flight mass spectrometry（UPLC-Q-TOF/MS）.CML and CEL were released from the baking foods through the process of sample degreasing, reduction reaction，precipitation and acid hydrolysis of acquired protein，treated by pre-column derivation with FMOC-Cl，and purified with HLB solid-phase extraction（SPE） column.Then the contents of CML and CEL in pretreated samples were determined by UPLC-Q-TOF/MS. All the target compounds exhibited good linearity（r>0.999） over the concentration range of 1-700ng/mL.The detection limits of CML and CEL were all 0.1mg/kg and the mean recoveries were in the range of 94.4%-108.3% with relative standard deviations（RSD,n=6） of 0.4%-6.2%.The method was accurate and sensitive，and was suitable for the detection of CML and CEL contents in baking foods.关键词：ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry（UPLC-Q-TOF/MS）;baking foods;Nε-（carboxymethyl）lysine（CML）;Nε-（carboxyethyl）lysine（CEL）
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发布时间： - 摘要：A multi-residue method was established for the simultaneous determination of 16 sedative residues（e.g. xylaznie，methaqualone，diazepan，promethazine，oxazepam，carazolol，chlordiazepoxide，zolpidem，chlorpromazine，acetopromaizine，azaperone，azaperol，propionylpromazin，haloperidol，droperidol，perphenazine） in pork using solid phase extraction/ultra performance liquid chromaography-tandem mass spectrometry（LC-MS/MS）.The homogenized samples were hydrolyzed with NaOH,then the analytes were extracted with HCl and cleaned up with an Oasis MCX SPE column. After evaporated to dryness under nitrogen and reconsituted，the reconstituted solution was filtrated through a 0.22μm syringe filter. Chromatographic separation was performed on a Waters ACQUITY UPLC BEH C18（2.1mm×100mm,1.7μm） column. The qualitative and quantitative detections of 16 analytes were operated by electrospray ionization-tandem mass spectrometry under the positive mode using multiple reaction monitoring（MRM） mode，with the external standard method. The matrix matching external standard method was used for quantitation analysis. All sedative residues have good linear relationship in the certain concentration range with correlation coefficients（r2） not less than 0.9968.The limits of detection（LOD） and quantitation（LOQ） for 16 sedative residues were in the range of 0.01-0.05μg/kg and 0.1-0.5μg/kg，reapectively. The average recoveries at three spiked concentration levels varied from 71.6% to 112%，and the relative standard deviations（RSD） were 2.9%-15.8%.The method was of high sensitivity，simplicity，reliability and low cost, and was suitable for the simultaneous determination of 16 sedative residues in livestock products.关键词：solid phase extraction;ultra performance liquid chromatography-tandem mass spectrometry;sedative;livestock products
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发布时间： - 摘要：A UPLC-Q-TOF-MS method was developed for the analysis and identification of main chemical constituents in the extract of Cordyceps liangshanensis, by an Agilent SB-C18（50mm×4.6mm，1.8μm） column with gradient elution using of 0.1% formic acid in water and acetonitrile as mobile phase at a flow rate of 0.25mL/min.The column temperature was set at 30℃.MS analysis was based on information associated mode（IDA） with positive and negative ions collection. By using feature of PeakView such as Formula Finder，matching the mass spectrometry data of each chromatographic peak in the database and the cleavage law of each peak′s level two fragment，total of 27 compounds in Cordyceps liangshanensis were identified，in which 8 compounds in Cordyceps substance had never been reported before. The main chemical constituents include alkaloids，glycosides，nucleosides，amino acids，etc. The method is accurate，reliable and efficient，and is suitable for the rapid identification of ingredients in Cordyceps liangshanensis. It provides a reference for the development and utilization of Cordyceps liangshanensis and clarification of its efficacy and material basis.关键词：Cordyceps liangshanensis;UPLC-Q-TOF-MS;cleavage law;chemical constituents
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发布时间： - 摘要：A simple and sensitive electrochemical method was developed for the determination of chlorogenic acid based on Nb2O5/reduced graphene oxide（RGO） nanocomposites modified glassy carbon electrode（Nb2O5/RGO/GCE）.Nb2O5/RGO composite was synthesized by a hydrothermal reduction using NbCl5 and graphene oxide（GO），and its morphology was characterized by scanning electronic microscopy（SEM）.Electrochemical behaviors of chlorogenic acid on Nb2O5/RGO/GCE were studied by cyclic voltammetry（CV） and square wave voltammetric(SWV) methods.The results showed that the Nb2O5/RGO composite displayed a remarkably enhanced electrochemical activity toward the oxidation of chlorogenic acid.Conditions influencing the detection process，such as pH value of buffer solution，scan rate and accumulation time，were optimized．Under the optimized conditions, the oxidation peak current of chlorogenic acid has a good linear relationship with concentration of chlorogenic acid in the range of 5.0×10-7-1.2×10-5mol/L，with a detection limit（S/N=3） of 2.0×10-7mol/L.The proposed method was applied in the determination of chlorogenic acid in pharmaceutical products，and the spiked recoveries were in the range of 96.6%-101.5%．With good sensitivity and stability，the developed method was successfully applied in the determination of chlorogenic acid in pharmaceutical products.关键词：nanocomposite;reduced graphene oxide;chlorogenic acid;Nb2O5 nanorod
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发布时间： - 摘要：A molecularly imprinted polymer to recognize four flavanones（hesperetin，hesperidin，naringenin，naringin） was prepared via precipitation polymerization using hesperetin as template molecule，2-vinylpyridine（2-VP） as functional monomer，and ethylene glycol dimethacrylate（EGDMA） as cross-linking agent. The optimal functional monomer and ratio were selected by UV spectrum method，and the optimized synthesis conditions were obtained. The molecularly imprinted polymer（MIP） and non-molecularly imprinted polymer（NIP） were characterized by scanning electron microscopy（SEM），Fourier transform infrared spectroscopy（FTIR） and static adsorption experiments. The MIP and NIP were used as selective sorbents for the comparative determination of naringin，hesperidin，naringenin，hesperetin.The results showed that the MIP had higher selective adsorption capacity to four flavanones than the NIP，and the relative selectivity coefficients（Ie） were 1.40，1.39，1.59 and 2.89，respectively. A molecularly imprinted solid phase extraction（MISPE）column filled with the polymer material was prepared to enrich and separate four flavanones in Citrus aurantium.In the optimum conditions，four flavanones of the Citrus aurantium was extracted by solid phase extraction.The results showed that the extraction efficiencies for four flavanones were 72.6%（naringin），61.1%（hesperidin），95.4%（naringenin） and 93.5%（hesperetin），respectively. The MISPE with neglectable matrix interference exhitited a good separation effect and greatly improved the extraction efficiencies for four flavanones in Citrus aurantium.关键词：molecularly imprinted polymer(MIP);high performance liquid chromatography（HPLC）;flavanones;hesperetin;citrus aurantium
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发布时间： - 摘要：A new method was developed for the rapid determination of diclazuril，toltrazuril，toltrazurilsulfone and toltrazurilsulfoxide residues in foods of animal origin by on line cleanup liquid chromatography-high resolution benchtop quadropole/obitrap mass spectrometry（HRMS） .The samples were extracted with acetonitrile，and purified on a Cyclone column.The analytes were eluted from the exaction column and put into a C18 analytical column prior to chromatographic separation and detection in full scan/ddMS2 mode.The calibration curves were linear in the range of 0.5-50 ng/mL with correlation coefficients more than 0.999 4.The limits of quantitation（LOQ） were 2 μg/kg.Average recoveries of the analytes in four matrices ranged from 80.2% to 110.5%，with relative standard deviations of 2.8%-9.7%.With simple pretreatment，low matrix effects,this method could be used for the rapid confirmation with accurate mass of quasi molecular ion，retention time，isotope ratio and qualitative fragments.关键词：on-line cleanup;obitrap high resolution mass spectrometry;diclazuril;toltrazuril;toltrazurilsulfone;toltrazuril sulfoxide;foods of animal origin
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发布时间： - 摘要：A method was developed for the rapid and simultaneous determination of 11 penicillins in fishery products by pass-through SPE purification with liquid chromatography tandem mass spectrometry（LC-MS/MS）．The samples were extracted with acetonitrile-water（80∶20，by volume），and then cleaned up with an Oasis PRiME HLB pass through SPE column.The separation of 11 penicillins were performed on a Kinetex XB-C18（2.1 mm×100 mm，2.6 μm） column by using a mixture of 0.05% formic acid and acetonitrile containing 0.05% formic acid as mobile phase.Qualitative and quantitative analyses of the analyte were carried out under the multiple reaction monitoring（MRM） mode with positive electrospray ionization．And the isotope internal standards were employed for the quantification.The calibration curves were linear well in corresponding concentration ranges,with correlation coefficient over 0.99.The detection limits ranged from 0.30 μg/kg to 1.5 μg/kg.The average spiked recoveries for 11 penicillins were between 85.5%and 110% with relative standard deviations（RSDs） of 5.9%-14.3%．The proposed method is accurate，sensitive and high-efficient，and is practical for the determination of penicillins in fishery products．关键词：penicillins;pass through solid phase extraction;liquid chromatography tandem mass spectrometry（LC-MS/MS）;fishery products
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发布时间： - 摘要：The application effect of isoelectric points（pI） of peptide and protein drugs containing different molecular weights and complex charge heterogeneity was evaluated by capillary isoelectric focusing electrophoresis-whole column imaging detection（cIEF-WCID ）.The pI of standard polypeptide was mensured repeatedly to verify that cIEF-WCID had a high accuracy and a good repeatability（RSD<0.50%）.Four serum protein isomers had achieved baseline separation.Gan Lai insulin was detected only a single characteristic peaks（pI 5.95±0.01） when repeating the test.The proportion differences of the characteristic peakPI were significant，when comparing the recombinant human growth hormone bulk and final，and the final appeared new characteristic peaks.Comparing the imported and domestic Avastin，manufacturer 1 and 3 were found to be consistent with the innovator drug，and the migration behavior of main component in manufacturer 1 was highly consistent with the innovator drug，however，the charge heterogeneity of manufacturer 2 was influenced because of lose K，N-term pyro-Glu.The optimized pI detecting conditions of the recombinant human follicle stimulating hormone were obtained by studying co-solvent concentration，electrolyte and focusing time,namely Co-solvent:2 mol/L urea，ampholytes at pH 2.5-5.0 and pH 3.0-10.0 mixing by 1∶1，and focus voltage:1 000 V（1 min） to 1 800 V（4 min） and to 2 200 V（1 min）.cIEF-WCID was fast and accurate，and it owned excellent resolution and reproducibility，especially，it could trace the focusing process of the analytes.Therefore，it was fit for analysing complex charge heterogeneity of protein drugs .关键词：capillary isoelectric focusing electrophoresis-whole column imaging detection（cIEF-WCID）;charge heterogeneity;recombinant protein drug;antibody;pharmaceutical research
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发布时间： - 摘要：In this paper，Au nanoparticles（Au NPs）/reduced graphene oxide（RGO） was used as the matrix of immunosensor to immobilize c reactive protein（CRP） antibody on the surface of glassy carbon electrode.A sandwich immunosensor was constructed using quinone dicarboxylic acid as tag.Under the optimal experiment conditions，the concentration of CRP was detected by differential pulse voltammetry.The linear range is 0.25-100 ng/mL with a detection limit of 0.08 ng/mL and a correlation coefficient of 0.997.This immunosensor provides a new simple means for the determination of c reactive protein.关键词：sandwich immunosensor;c reactive protein（CRP）;reduced graphene oxide;electrochemistry
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发布时间： - 摘要：A new method was established for the determination of thiencarbazone methyl，isoxaflutole and their metabolites RPA203328 and RPA202248 residues in corn and soil by dispersive solid phase extraction（d-SPE） combined with ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）.The samples were extracted with acidified acetonitrile（containing 1% formic acid），and acetonitrile phase was separated from sample solution through salting out phenomenon with sodium chloride.The acetonitrile solution was cleaned up by dispersive solid phase extraction.The analytes were determined by ultra performance liquid chromatography-tandem mass spectrometry.Factors affecting the extraction efficiency，such as type of extraction solvent，cleanup sorbent and instrumental condition，were investigated.The performance of this method was evaluated under the optimal conditions at the same time.The results indicated that the matrix effects of four target compounds in corn were more than 10%,and the matrix effects of the other three target compounds in soil were more than 10% except that for the RPA202248 was less than 10%.The calibration curves for all the analytes were linear in the range of 0.001-1.0 μg/mL with correlation coefficients of 0.994 5-0.999 5.The recoveries at spiked range of 0.005-0.1 mg/kg were in the range of 72.9%-116.5%，with relative standard deviations（n=5） of 0.75%-17.8%.The limits of quantitation were 0.005-0.01 mg/kg.With the advantage of quickness，high performance and environmental friendliness，the developed method is suitable for the determination of thiencarbazone methyl，isoxaflutole and their metabolites residues in corn and soil.关键词：dispersive solid-phase extraction（d-SPE）;ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）;thiencarbazone methyl;isoxaflutole;metabolites;pesticide residue;corn;soil
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发布时间： - 摘要：A method was developed for the determination of azithromycin in formula feed for fattening pigs by liquid chromatography-tandem mass spectrometry（HPLC-MS/MS）.The sample was extracted with acetonitrile under ultrasonic assistance.Oasis MCX solid phase extraction column was used for purification，and the chromatographic separation was performed on a Hypersil BDS C18 column（2.4 μm，100 mm×2.1 mm） with gradient elution using 0.05 mol/L ammonium acetate-methanol（1∶9） as mobile phase.The detection of azithromycin was performed with positive ion under multiple reaction monitoring（MRM） mode.The internal standard isotope dilution method was used for quantification.A good linearity（r2=0.999 1） was obtained for azithromycin in the range of 1-250 μg/L.The limit of detection（LOD，S/N≥3） and the limit of quantitation（LOQ，S/N≥10） of azithromycin in the formula feed were 2.8 μg/kg and 8.4 μg/kg，respectively.Average recoveries ranged from 87.0% to 106.6% for the formula feed at spike levels of 0.5，1，5，10 mg/kg.The intra-RSDs for azithromycin were 0.58%-5.4% and the inter-RSDs were 3.1%-5.4%.The method is accurate and sensitive，and the matrix interference is small.The method could be applied in the determination of azithromycin in formula feed.关键词：liquid chromatography tandem mass spectrometry（LC-MS/MS）;azithromycin;fattening pig;formula feed
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发布时间： - 摘要：A new fiber coating with a large specific surface area was prepared by direct acid pretreatment of NiTi alloy wire.The extraction performance of the prepared fiber was evaluated by high performance liquid chromatography（HPLC） using aromatic compounds as model analytes .Good extraction efficiency and selectivity were achieved for different types of ultraviolet filters.The key parameters influencing the extraction efficiency were optimized for 2-hydroxy-4-methoxybenzophenone(BP-3)，2-ethylhexyl p-methoxycinnamate(EHMC)，2-ethylhexyl-4-（dimethylamino）benzoate(OD-PABA) and 2-ethylhexyl 2-hydroxybenzoate(EHS).Under the optimized conditions，the linearity was obtained in the range of 0.1-300 μg?L-1.The limits of detection ranged from 0.025 μg?L-1 to 0.097 μg?L-1.The intra day and inter day precisions for the proposed method with the single fiber were in the ranges of 4.9%-5.8% and 5.5%-6.4%，respectively.Its fiber-to-fiber reproducibility ranged from 6.3% to 7.1%.The proposed method was successfully applied in the concentration and determination of target UV filters in environmental water samples.The resulting fiber is very stable in SPME procedure,and could be rapidly prepared in a highly reproducible manner.关键词：solid phase microextraction（SPME）;high performance liquid chromatography（HPLC）;ultraviolet filters;enrichment;sample preparation
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发布时间： - 摘要：To establish an effective analysis method for evaluating the quality of edible oil is of great significance to ensure the safety of edible oil market.Principal component analysis（PCA）and cluster analysis（CA）were used to analyze the low field nuclear magnetic resonance（LF-NMR） T2 relaxation characteristics of 9 kinds of normal edible oil and 100 catering waste oil samples.The results indicated that good classification of refined edible oil according to their vegetable types could be achieved by PCA,and the distributions of different vegetable oils on the PCA plot have clear boundaries.While for the discrimination of authentic vegetable oil and the catering waste oil,good identification results could be achieved by CA（Euclidean distance=5）.After the introduction of 30 testing samples,the overall correct classification rate was still as high as 94.49%,and the misjudgment rate was only 5.51%.Therefore,LF-NMR combined with chemometrics method is feasible for rapid classification of edible vegetable oils and discrimination of catering waste oils.关键词：low-field nuclear magnetic resonance（LF-NMR）;edible oil;catering waste oil;principal component analysis(PCA);cluster analysis(CA)
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发布时间： - 摘要：A high performance liquid chromatography-tandem mass spectrometric（HPLC-MS/MS） method was developed for the rapid determination of metronidazole（MNZ），metronidazole-OH（MNZOH）,dimetridazole（DMZ），hydroxydimetridazole（HMMNI）,ronidazole（RNZ）,ipronidazole（IPZ）,ipronidazole-OH（IPZOH） residues in feed.The samples were extracted with 0.1 mol/L pH 8.0 phosphate buffer and ethyl acetate-acetone（70∶30，by volume），then cleaned up with matrix solid phase dispersant primary secondary amine（PSA）.The extracts were defatted with hexane and cleaned up by liquid-liquid partition.The target compounds were detected by electrospray ionization（ESI） in positive mode using multiple reaction monitoring,and quantified by the isotope internal standard method.No solid phase extract（SPE） procedure was adopted，which made sample preparation simple and efficient.The calibration curves for seven target compounds were linear in the range of 2.0-100.0 μg/L with correlation coefficients more than 0.99.Average recoveries at spiked levels of 5.0-25.0 μg/kg were between 72.4% and 95.6%，with relative standard deviation less than 12.5%.The limits of detection（LOD） were 2.5 μg/kg，and the limits of quantitation（LOQ） were 5.0 μg/kg.关键词：high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS);feed;nitroimidazoles;metabolites
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发布时间： - 摘要：The concentrations of heavy metals（Cd，Cr，Cu，Fe，Mn，Ni，Pb，Sr，Zn） in several South China Medicines were investigated，the speciation of heavy metals were analyzed by the continuous extraction method，and the impact of decoction on contents and speciation of heavy metals were also studied.The results showed that，the concentrations of Cr，Pb，Zn were high in several medical herbs，and the total concentrations of heavy metals in Morinda officinalis were higher than the values of the limit standard.Cr，Cu，Mn，Ni，Pb and Zn in raw medicinal herbs mainly existed as the organic fraction and residual fraction，Fe and Sr mainly existed as residual fraction.A large amount of heavy metals in South China Medicine released to the medicine soup by decocting.Cu，Mn，Cr，Pb and Zn in medicine soup mainly derived from the exchangeable，carbonate bound and organic speciation in the medicinal herbs.Sr，Ni and Fe in medicine soup mainly derived from their residual fraction.The total concentrations and non residual amounts of Cu，Mn，Cr，Pb and Zn were required to keep in control to reduce the concentrations of heavy metals in the medicine soup，and the total concentrations of Fe，Ni and Sr were required to be in control in minority herbs.关键词：south China medicine;heavy metal;speciation;decoction;quality control
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发布时间： - 摘要：A pressurized capillary electrochromatographic（pCEC） method was developed for the determination of the main anthraquinones,including rhein，emodin，aloe emodin，chrysophanol and physcion in root of Polygonum cuspidatum.The separation was performed on a reversed phase EP-100-20/45-3-C18 column（total length of 45 cm,effective length of 20 cm，diameter of 100 μm，ODS packing inside for 3 μm）.The mobile phase was composed of 20 mmol/L NaH2PO4（pH 4.7）-acetonitrile（15∶85） at a flow rate of 0.04 mL/min.Under the optimum conditions including running voltage of +5 kV，UV detection wavelength of 254 nm，the limits of detection（S/N=3）were in the range of 0.60-2.54 μg/mL for rhein，aloe emodin，emodin，chrysophanol and physcion，respectively,and the linear detection ranges were 3.57-162.68 μg/mL with correlation coefficients not less than 0.998 2.The established method was used in the analysis of anthraquinones in polygonum cuspidatum with good results.The recoveries at three spiked levels ranged from 91.1% to 101.2%，with relative standard deviations（RSD） of 0.03%-3.6%.关键词：pressurized capillary electrochromatography;polygonum cuspidatum;anthraquinone
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发布时间： - 摘要：A liquid chromatography-tandem mass spectrometric（LC-MS/MS） method was developed for the determination of dimethyl yellow and diethyl yellow in dried bean curd，chili sauce，tofuru，dried beancurd sticks and biscuit.In this study，based on the chemical structures of dimethyl yellow and diethyl yellow，the sample was first extracted using acetonitrile solution，and the extract was then acidified and purified with a Bond Elut Plexa PCX cation anion exchange cartridge.After drying and re dissolvation，the analytes were separated by reverse phase LC using a C18 column,followed by detection using triple quadrupole mass spectrometry with positive electrospray ionization in multiple reaction monitoring（MRM） mode.The limits of quantitation were both 0.50 μg/kg.The recoveries of dimethyl yellow and diethyl yellow in food samples at three spiked levels of 0.50，5.0，80 μg/kg were in the range of 76.1%-93.0% with relative standard deviations（RSDs） of 1.7%-7.4%.The method could meet the requirement for rapid screening and quantitative analysis of dimethyl yellow and diethyl yellow in foods.关键词：dimethyl yellow;diethyl yellow;solid phase extraction;liquid chromatography-tandem mass spectrometry（LC-MS/MS）
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发布时间： - 摘要：A modified glassy carbon electrode（GCE） was prepared by electrodeposition of platimum nanoparticles（Pt NPs） and electropolymerization of 3，4-ethoxylenedioxythiophene（EDOT） onto the surface of GCE，and scanning electron microscope was employed to investigate its surface morphology.The result showed that the uniform film of poly-3，4-ethoxylenedioxythiophene（PEDOT） and aggregated Pt NPs adhered to the electrode surface.The electrochemical behaviors of chlorogenic acid（CGA） at different electrodes indicated that this modified electrode could significantly improve the electrochemical redox signal of CGA compared with the bare GCE.The experimental conditions e.g.pH value,scan rate and accumulation time were optimized.Under the optimal conditions，the oxidation peak current of CGA was linear in the concentration range of 0.2-100 μmol/L，with a detection limit of 0.05 μmol/L.The sensor was successfully used to detect CGA in real sample of Shuanghuanglian injection，with spiked recoveries of 97.7%-1021%.Furthermore，the interaction between CGA and DNA was investigated，and the binding number and the binding constant were calculated to be 3 and 1.62×103 L/mol,respectively.The result could provide not only a reference for the pharmacological research of CGA，but also a theoretical guidance for the selection of similar drugs.关键词：chlorogenic acid;modified electrode;PEDOT;platimum nanoparticles;DNA
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发布时间： - 摘要：A method was established for the detection of 10 whitening and 2 prohibited components in cosmetics by high performance liquid chromatography（HPLC）.Low fat cosmetics samples such as make up water and lotion were extracted directly with 0.02 mol/L potassium dihydrogen phosphate solution（pH 6.0）.High fat cosmetics samples and wax based and powder cosmetics were well dispersed with 2.5 mL dichloromethane first,then extracted with 0.02 mol/L potassium dihydrogen phosphate solution（pH 6.0）.The sample solution were centrifuged at a speed of 9 500 r/min,then filtered through a 0.22 μm syringe filter.The filtrate were analyzed on an Eclipse XDB-C18 column （250 mm×4.6 mm,i.d 5 μm） using 0.02 mol/L potassium dihydrogen phosphate （pH 6.0）-methanol as mobile phase at a flow rate of 1.0 mL/min.The temperature of the column was set at 25 ℃.The detection wavelengths were 230 nm and 250 nm.The standard working curves of 12 compounds had good linear relationships（r>0.999 0） in concentration range of 2.5-100 mg/L.The quantitation limits（S/N=10） of 12 compounds were in the range of 0.006 5%-0.025%.The recoveries of 12 analytes at spiked levels of 0.025%-0.5% were in the range of 87%-102%with relative standard deviations less than 4%.With the advantages of simplicity,high recovery and good precision, this methed was suitable for the determination of 10 whitening and 2 prohibited components in cosmetics.关键词：cosmetics;whitening component;high performance liquid chromatography（HPLC）
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发布时间： - 摘要：The pipe tobacco processed with different kinds of water was analysed by low field nuclear magnetic resonance（LF-NMR） technique.The moisture content and changes of water distribution in the samples treated by different processes were studied in detail.The study result showed that the water species has a significant influence on the pipe tobacco processed by moisture content and its distribution.The total moisture contents of the samples treated with reverse osmosis water and magnetized water are generally 0.43% and 0.72% higher than that with tap water,respectively.The appropriate KLK processing temperature is in the range of 140-150 ℃，and the appropriate HXD processing temperature is 180-210 ℃.关键词：LF-NMR;tobacco;water distribution;KLK;HXD
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发布时间： - 摘要：A quantitative nuclear magnetic resonance(qNMR) method was established for the determination of the organic impurities contents in the reference material hexanitrohexaazaisowurtzitane(CL-20).The main impurities in the reference material were confirmed to be ethyl acetate and monoacetylpentanitrohexaazais-owurtzitane(MPIW) by analyzing the NMR spectrum.Hexamethyldisiloxane in CCl4 solution with its NMR peak of δ 0.06 was selected as the internal standard which was added into the CL-20 in acetone-d6 solution without tetramethylsilane(TMS).After investigating the effect of delay time (D1) and number of sampling(NS) on quantitative NMR experiments,the experimental parameters were chosen with D1 of 20 s and NS of 32.Using the optimized experiment parameters,it was found that the contents of ethyl acetate and MPIW were 0.035 16% and 0.156 2%,with RSDs of 0.91% and 0.86%,respectively.关键词：quantitative nuclear magnetic resonance(qNMR);1H NMR;CL-20;organic impurity
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发布时间： - 摘要：Contents of Pb2+ and Ni2+ in soy sauce were determined by the online derivation and HPLC method with wet digestion.Sodium diethyldithiocarbamate（NaDDTC） was used as the derivtive agent for heavy metal ions.The experimental conditions were as follows：chromatography column:a Hypersil ODS2 C-18（5 μm,250 mm×4.6 mm） column，mobile phase：MeOH-H2O-sodium diethyldithiocarbamate（63.5∶35∶1.5）.The calibration curves for Pb2+ and Ni2+ were linear in the range of 0.5-50 μg/mL with correlation coefficients of 0.998 2 and 0.999 0，respectively.The limits of detection were 0.3 μg/mL and 0.2 μg/mL，respectively，with recoveries of 88.1%-91.8%.The method has the advantages of simplicity，good accuracy and precision，and could be used as an alternative method for the determination of heavy metal ions in real soy sauce samples.关键词：high performance liquid chromatography（HPLC）;online derivation;soy sauce;heavy metal ions
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发布时间： - 摘要：Estrogen is a kind of steroid hormone，belonging to endocrine disruptors，which seriously interfere with the normal endocrine function of human and wildlife.Therefore，it is quite necessary to develop a simple and rapid method for the sensitive determination of estrogen present in the environment to protect public and environment health.Aptamers are selected in vitro by systematic evolution of ligands by exponential enrichment（SELEX），and are single stranded DNA or RNA molecules that can bind to various targets with high sensitivity and specificity.Aptamer has been widely used in analysis field because of its several overwhelming advantages over antibodies，such as target diversity，high stability，easy of synthesis and modification for applications.In this review，the researches on estrogen aptamer selection and aptamer based detection methods were summaried，and the development trend of aptasensor application in estrogen detection was also discussed.关键词：estrogen;aptamer;colorimetry;fluorescence;electrochemistry;review
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