最新刊期
卷 33 ， 期 8 ， 2014
- 摘要：The new matrix of Nd2Fe14B powders with high magnetic and super paramagnetic properties was used as a muddler magnetic supply in order to prepare sorptive extraction stir bars based on the molecular imprinting technique.It was carried out by a stepwise polymerization using malachite green（MG） as template,methacrylic acid（MAA） as functional monomer,ethylene glycol dimethacrylate（EGDMA） as cross linking agent.The experimental conditions such as extraction and desorption times,pH value and salt concentration were optimized in stir bar sorptive extraction（SBSE） process.Coupled with high performance liquid chromatography（HPLC），the SBSE was applied in the extraction and determination of MG in real samples.The experimental results indicated that under the optimized experimental conditions,the method showed good linearity in the range of 10-500 μg/L with detection limits of 103-215 ng/L and spiked recoveries of 87.3%-94.1%.关键词：malachite green;molecularly imprinted polymer;HPLC;stir bar sorptive extraction
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发布时间： - 摘要：A method for the determination of nine nitrosamines in water by ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS） was proposed.After comparison of effects on detection signals of different mobile phases,different SPE cartridges as well as different reconstitution solvents,methanol and 10 mmol/L ammonium bicarbonate water solution were selected as mobile phases.A coconut charcoal cartridge was selected as pre-treatment SPE cartridge and pure water was selected as reconstitution solvent.Based on the optimum sample pretreatment procedures and instrument conditions,standard calibration curves for the analytes were obtained.The linear calibrations ranged from 5 ng/L to 150 ng/L with correlation coefficients（r2） of 0.997-0.999.The limits of detection（LODs） and limits of quantitation（LOQs） for nine nitrosamines were in the range of 1.3-2.8 ng/L and 4.0-8.5 ng/L,respectively.The intra- and inter-day relative standard deviations（RSDs） were in the range of 3.5%-8.4% and 2.8%-7.5%,respectively.The method recoveries were in the range of 80.4%-109.6% for the three different types of water samples at two spiked concentration levels.Nine nitrosamines in drinking water from three water treatment plants as well as effluents from three wastewater treatment plants were detected.The results showed that,among the nitrosamines，the NDMA concentration was the highest,with 10.2 ng/L and 45.6 ng/L in drinking water and wastewater effluent,respectively.关键词：UPLC-MS/MS;nitrosamines;solid phase extraction;reconstitution solvent
- 1993
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- 1100
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- 15
发布时间： - 摘要：A method was developed for the determination of 33 kinds of steroid hormones（including androgens,estrogens,progestogens,corticosteroids and steroids-like chemicals） in porcine plasma.The analytes in samples were extracted with methyl tert-butyl ether by vortex oscillation.The separation of analytes was achieved by gradient elution on a Xselect-C18 column（3.5 μm,2.1 mm×100 mm） under positive mode and an Extend-C18 column（3.5 μm,2.1 mm×100 mm） under negative mode.All steroids were detected by high performance liquid chromatography combined with tandem mass spectrometry（HPLC-MS/MS） and quantified by the external standard method.The calibration curves of 33 steroids were linear in the certain concentration range with correlation coefficients（r） more than 0.99.The average recoveries of steroids at three spiked levels ranged from 50.9% to 119.5% with relative standard deviations（RSDs） of 2.3%-9.8%.The limits of quantitation（LOQ,S/N≥10） were in the range of 0.05-40.00 ng/mL.The method was used for the determination of steroids in real samples collected from the large scaled livestock farms in Beijing and 10 kinds of steroids（including testosterone,progesterone,cortisone,androstenone,hydrocortisone,4-androstenedione,corticosterone,cortexolone,21-hydroxyprogesterone and 17α-hydroxyprogesteron） were detected.The results showed that the method was simple,sensitive and reproducible,and could be applied in the determination of steroids in porcine plasma.关键词：steroids;hormone;high performance liquid chromatography tandem mass spectrometry(HPLC-MS/MS);porcine plasma
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- 946
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- 4
发布时间： - 摘要：A multi residue analytical method by liquid chromatography-high resolution mass spectrometry was developed for the simultaneous detection of gymnodimine(GYM),spirolides(SPX1),okadaic-acid(OA-C),pectenotoxins(PTX 2),chloroamphenicol,florfenicol and 14 sulfonamides in shellfish tissues.The samples were extracted with methanol,defatted with n-hexane,and back-extracted with ethyl acetate and purified by votexing with ODS.The extract was separated on an Agilent ZORBAX SB-C18 column(3.0 mm×100 mm,1.8 μm) and detected with high resolution mass spectrometry.The results showed that high correlation coefficients(r2＞0.99) of the anaytes were obtained within their respective linear ranges.The limits of quantitation(LOQ) of 4 shellfish biotoxins(SPX1,OA-C,GYM and PTX 2) were 0.1,2.0,0.5，0.5 μg/kg,respectively.The average recoveries for low,intermediate,and high spiked levels ranged from 70.1% to 105.8% with RSDs of 10.1%-14.8%．The proposed method was accurate,rapid and reliable,and could be applied in the qualitative and quantitative analysis of shellfish biotoxins and other toxic substances in shellfish.关键词：shellfish;liquid chromatography-high resolution mass spectrometry;shellfish iotoxin;chloroamphenicol;florfenicol;sulfonamide;QuEChERS
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发布时间： - 摘要：The pyrolysis behavior of latent fragrant compound N-(2,3-pyrazinediformyl) alanine methyl ester was investigated by on-line pyrolysis-gas chromatography-mass spectrometry(Py-GC-MS).Firstly,the new compound N-(2,3-pyrazinediformyl) alanine methyl ester was synthesized by amidation using 2,3-pyrazinedicarboxylic acid as material,and its structure was confirmed by X-ray single crystal diffractometry(XRD),1H NMR,13C NMR,IR and HR-MS.In air atmosphere,the compound was pyrolyzed at 300,600 and 900 ℃,respectively.The pyrolysis products were directly introduced into GC-MS to analyse qualitatively and semi-quantitatively.The results indicated that 48 pyrolysis products were detected,including the flavorous substances such as pyrazines,4-methoxy-benzenemethanol and 4-methoxy-benzaldehyde.The pyrolysis temperature affected the pyrolysis pattern and the relative content of the products.The relative content of acetic acid was the highest at 300 ℃ and 600 ℃,and that of pyrazine was the highest at 900 ℃.Compared with that of the pyrolysis at 300 and 600 ℃,the generated pyrazine derivatives sort and the relative content of pyrazine were the highest when pyrolyzing at 900 ℃.On the other hand,in the pyrolysis products with aroma characteristics,the relative contents of 4-methoxy-benzenemethanol increased monotonically with increase of pyrolysis temperature,while the relative content of 4-methoxy-benzaldehyde and benzaldehyde showed a decreasing tendency with a rise of temperature.The possible pyrolysis mechanism of N-(2,3-pyrazinediformyl) alanine methyl ester was preliminarily discussed based on the determined pyrolysates and quantitative changes with the temperature.It is a simple and rapid way to use Py-GC-MS technology in the separation and identification of pyrolysis products.关键词：pyrolysis-gas chromatography-mass spectrometry(Py-GC-MS);latent fragrant compound;N-(2,3-pyrazinediformyl) alanine methyl ester;pyrolysis behavior
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- 2
发布时间： - 摘要：A high performance liquid chromatographic method was developed for the simultaneous determination of ten synthetic cannabinoids in novel“spice”drugs.A Shim-pack XR-ODS C18（4.6 mm×250 mm，5 μm） column was used at 45 ℃.The mobile phase system contained methanol-acetonitrile（50∶50） and water,and the percentage of organic phase changed between 66% and 89.1% in a linear gradient elution.The flow rate was set at 1.0 mL/min,and the detection wavelength was 220 nm.Under the optimized conditions,ten synthetic cannabinoids were completely separated and determined in 33 min.Good linear relationships were obtained in the range of 1-100 mg/L with correlation coefficients of 0.999 9.The LODs were in the range of 0.10-0.50 mg/L.The intra-day relative standard deviations（RSDs） were in the range of 0.15%-1.37% and the inter-day RSDs were 0.55%-1.96%.The sample showed good stability under room temperature,freeze and three cycles of freeze-thaw conditions.This method was accurate,sensitive and rapid for the determination of common synthetic cannabinoids in novel“spice”drugs.关键词：high performance liquid chromatography（HPLC）;spice;synthetic cannabinoids
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发布时间： - 摘要：Water-soluble thioglycollic acid capped CdS quantum dots（QDs） were prepared using a simple method.CdS QDs were assembled on the surface of tin indium oxide（ITO） electrode through the electrostatic interaction between negatively charged thioglycollic acid on the surface of CdS and positively charged poly dimethyl diallyl ammonium（PDDA）.The CdS QDs modified ITO electrode showed a stable anodic photocurrent in the presence of triethanolamine（TEA） as an electron donor（or hole scavenger）.When the CdS QDs modified ITO electrode was immersed in Hg2+solution,an obviously enhanced photocurrent of CdS QDs was observed.The in-situ formation of HgS,a p-type semiconductor,on the surface of n-type CdS semiconductor led to the formation of a p-n junction,which facilitated the charge carrier transport and promoted electron-hole separation,triggered an obviously enhanced anodic photocurrent of CdS QDs.Effects of synthetic conditions such as molar ratio of Cd/S,pH value of reaction solution and reflux time on photoelectrochemical response of CdS QDs to Hg2+were investigated.Effects of pH value of the supporting electrolyte,applied potential and reaction time between CdS and Hg2+on photocurrent enhancement（I/I0） of CdS QDs by Hg2+were also investigated.Based on this,a sensitive Hg2+photoelectrochemical sensor was developed.The sensor showed a linear response to Hg2+in the concentration range of 4.0×10-8-2.0×10-5 mol/L,with a detection limit of 2.4×10-8 mol/L.The method was applied in the detection of Hg2+in lake water samples with recoveries of 98.3%–103.5%.关键词：CdS quantum dots（QDs）;photoelectrochemical sensor;mercury（Ⅱ） ion;p-n junction
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发布时间： - 摘要：A method was developed for the determination of residual amantadine,rimantadine and memantine in eggs by dispersive solid phase extraction and liquid chromatography with tandem mass spectrometry.The satisfactory separation was obtained after optimizing composition of mobile phase and column temperatures for rimantadine and memantine isomers.The samples were extracted with acetic acid acetonitrile,then purified by dispersive solid phase extraction method with PSA and C18 sorbent.After purification,the extract was dried under nitrogen,and the residues were dissolved in 0.1% formic acid-methanol(90∶10) and filtered through a 0.22 μm filter.The target compounds were analyzed by LC-MS/MS on an Acquity BEH C18 column using a mixture of 0.1% formic acid-methanol as mobile phase with gradient elution.The mass spectrometer was operated under multiple reaction monitoring(MRM) mode in positive mode.The samples were quantified by the isotope dilution and internal standard methods.Good linearities were obtained for amantadine,rimantadine and memantine at a concentration range of 0.10-10.0 μg/L with correlation coefficients more than 0.999.The limits of detection for three drugs were all 0.15 μg/kg,and the limits of quantitation were 0.50 μg/kg.The recoveries of three drugs in eggs at three spiked levels(0.50,0.75 and 1.0 μg/kg) were in the range of 96.2%-105.9%,with intra-assay relative standard deviations of 2.7%-4.5% and inter-assay relative standard deviations of 4.1%-5.3%.The results demonstrated that the method was suitable for the determination of amantadine,rimantadine and memantine in eggs.关键词：amantadine;rimantadine;memantine;liquid chromatography with tandem mass spectrometry;egg;residue
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发布时间： - 摘要：A liquid chromatography-tandem mass spectrometric(LC-MS/MS) method was developed for the simultaneous determination of benzo(a)pyrene and aflatoxins(B1,B2,G1,G2) in vegetable oil.The sample was extracted with ethyl acetate-hexane(1∶1),cleared up by GPC.The separation of target compounds were performed on an XDB C18 column(4.6 mm×50 mm,1.8 μm) at 25 ℃ with methanol and 10 mmol/L ammonium acetate solution as mobile phase by gradient elution at a flow rate of 0.25 mL /min.Then the samples were ionized using atmospheric-pressure photoionization ion source ionization,examined under multiple reaction monitoring(MRM) mode and quantified by the external standard method.The quantitation limits of benzo(a)pyrene and aflatoxins(B1,B2,G1,G2)were 0.3,0.5,1.0,1.0,1.0 μg/kg，respectively.The linear ranges of benzo(a)pyrene and aflatoxins(B1,B2,G1,G2) were 0.3-25,0.5-30,1.0-10,1.0-30,1.0-10 μg/kg,respectively,with correlation coefficients(r) of 0.999 6-0.999 9.The spiked recoverie of target compounds in vegetable oil were in the range of 80.3%-106.8%，with relative standard deviations of 4.0%-10.0%.The real sample tests showed that the method was simple and accurate,and could be used for the determination of benzo(a)pyrene and aflatoxins(B1,B2,G1,G2) in vegetable oil.关键词：LC-MS/MS;GPC;benzo(a)pyrene;aflatoxins;vegetable oil
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发布时间： - 摘要：A turbidimetric method which could verge on a homogeneous reaction system was obtained.The method was applied in study of recombinant human lysozyme activity,and the related operation procedures and quality standards were established.In this research,microscopic counting method was used for the quality control of substrate bacteria liquid.The mixing manner of enzyme and bacteria liquid was improved,so as the amount of enzyme used for detection.“Double line method” was adopted to optimize the reaction time interval for activity detection.Also,the content of recombinant human lysozyme was detected accurately.By means of microscope count method,the bacteria number in reaction substrate was kept at about 1.1×108/mL,and the concentration of the reaction substrate was 0.3 mg/mL.To approach the homogeneous system,the reaction liquid of lysozyme and bacteria was mixed by sucking-expelling method in the sample pool.The optimum amount of lysozyme was 3 μg,the optimum reaction time was confirmed as 0-60 s.According to the operation procedure of enzymatic activity detection,the standard for activity of recombinant human lysozyme was confirmed as 45 000-65 000 U/mg,the RSD of intra-day and inter-day were both less than 5%.Lowry method was chosen for the content determination of recombinant human lysozyme,and the protein content was （1.0±0.1） mg/mL.Stability of the optimized method was improved obviously,also,the operation was convenient and the detection result was reliable.Furthermore,the optimized method was verified and accepted by three research institutes and enterprises.The quality standards and operational procedures were established with important practical reference value.关键词：recombinant human lysozyme;turbidimetry;double line method;Lowry method
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- 4
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发布时间： - 摘要：Tyrosinase(Tyr) was stably immobilized on the glassy carbon electrode modified with functional graphene oxide(GO) with ethylenediamine as arm molecule.The physical and chemical behaviors of Tyr immobilized on functional GO were characterized by X ray photoelectron spectrum and electrochemical impedance spectroscopy,which demonstrated that functional GO could facilitate the electron exchange between the active center of Tyr and modified electrode.The direct electrochemistry and electrocatalysis behaviors of Tyr on the modified electrode were characterized by cyclic voltammetry,which indicated that Tyr immobilized on the modified electrode displayed a direct and adsorption-controlled redox reaction.Under the optimum conditions,the oxidation current was proportional to hydroquinone(HQ) concentration in the range of 3.0-200.0 μmol/L with correlation coefficient of 0.999 5 and detection limit(S/N=3) of 1.0 μmol/L.Moreover,the proposed electrochemical biosensor also exhibited a good reproducibility，stability and selectivity，and was used to detect HQ in real water samples with satisfactory results.关键词：graphene oxide;tyrosinase;ethylenediamine;hydroquinone;biosensor
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- 1
发布时间： - 摘要：A method based on high performance liquid chromatography-hydride generation-atomic fluorescence spectrometry（HPLC-HG-AFS） for simultaneous determination of organotin compounds,e.g.dimethyltin（DMT）,trimethyltin（TMT） and diphenyltin（DPhT） in plastic samples was established.Various experimental parameters were optimized.DMT,TMT and DPhT were chromatographically separated on an Agela-C18 column by using mobile phase of methanol-water-acetic acid-triethylamine（60∶40∶1∶0.03） at a flow rate of 0.7 mL?min-1.The hydrogenation of organotin compounds reacted in the environment of 5% HCl and 2% KBH4.The different concentration mixed organotin compounds（DMT,TMT and DPhT） standard were tested.The experimental results indicated that the calibration curves were linear in the range of 10-200 μg/L with correlation coefficients（r） more than 0.992.Different plastic samples were dissolved completely in tetrahydrofuran（THF）,the impurities of high molecular weight were deposited by mixing methanol in THF solutions.The solutions were tested by HPLC-HG-AFS after high speed centrifugation and filtration.The average recoveries of DMT,TMT and DPhT in PVC,PC,PS,AS and ABS samples ranged from 75.1% to 109.1%,with relative standard deviations of 3.7%-10.7%.The detection limits of DMT,TMT and DPhT were 0.009 ,0.012 mg/kg and 0.025 mg/kg,respectively.关键词：organotin compounds;plastic products;high performance liquid chromatography（HPLC）;atomic fluorescence spectrometry
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- 962
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发布时间： - 摘要：A reversed phase high performance liquid chromatography-fluorescence detection(RP-HPLC/FLD) method was developed for the determination of thiamine(T) and thiamine monophosphate(TMP),thiamine diphosphate(TDP) in human plasma，erythrocytes and urine.After deproteinization with perchloric acid and derivation with potassium ferricyanide,the sample was separated on a C18 column(250 mm×4.6 mm,5 μm i.d.) at 20 ℃.A gradient programme was carride out at flow rate of 0.8 mL/min using 0.2 mol/L KH2PO4( including 0.000 3 mol/L TBAH,pH 7.0 )-methyl alcohol and methyl alcohol-water as eluent.The excitation and emission wavelengths were set at 365 nm and 435 nm,respectively.The results showed that T,TMP and TDP could be completely separated within 18 min.The calibration curves were linear in the range of 0.5-20.0 μg/L for T and TMP,and 5.0-200.0 μg/L for TDP,with correlation coefficients of 0.99,0.98,0.99,respectively.The spiked recoveries of three compounds in plasma,erythrocytes and urine were in the range of 86.8%-110.2% with relative standard deviations(RSDs) of 2.5%-10.9%.The limits of detection(LODs) and limits of quantitation(LOQs) for T,TMP,TDP in plasma and erythrocytes were in the range of 0.03-0.35 μg/L,and 0.09-1.18 μg/L,respectively.The LODs and LOQs of T in urine were 1.58 μg/L and 5.26 μg/L,respectively.The developed method was sensitive and precise,and could meet the demands for clinical application.关键词：reversed phase high performance liquid chromatography-fluorescence detection(RP-HPLC/FLD);thiamine and its phosphate ester;plasma;erythrocytes;urine
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- 1068
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- 0
发布时间： - 摘要：A method of nuclear magnetic resonance（qNMR） was established for the simultaneous determination of eight kinds of biogenic amine hydrochlorides（e.g.spermine tetrahydrochloride,spermidine trihydrochloride,histamine dihydrochloride,putrescine dihydrochloride,cadaverine dihydrochloride,2-phenylethylamine hydrochloride,tyramine hydrochloride and D1-octopamine hydrochloride）.The hydrogen of eight kinds of biogenic amine hydrochlorides were assigned by 1H and 1H-1H COSY spectra,and the ethyl paraben（certified reference material,GBW（E）100064 ） was selected as the internal standard for the purity detection of biogenic amine hydrochlorides.The experimental parameters of NMR were extensively investigated to achieve optimal conditions.It was found that relaxation delay was the main factor affecting the accuracy of the quantitative analysis of qNMR.Two certified reference materials（CRM）,ethyl paraben and p nitrotoluene,were chosen for the experiments of parameter selection.The experimental results indicated the five times of T1 was not sufficient for the accuracy of quantitative analysis of qNMR.The change of pulse width would not influence the experimental results of qNMR,but the use of narrow pulse width could reduce the time of relaxation delay.The eight kinds of biogenic amine hydrochlorides were detected by qNMR,and the purities for them were 99.0%,99.1%,99.4%,99.1%,99.3%,99.6%,99.6%,93.3%,with relative standard deviations（RSD） of 0.2%,0.2%,0.3%,0.2%,0.2%,0.1%,0.2%,0.3%，respectively.关键词：biogenic amine hydrochloride;biogenic amine;quantitative nuclear magnetic resonance;nuclear magnetic resonance;purity assessment
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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 tyrosine isomers（o-tyrosine and m-tyrosine） in protein-containing functional food.The sample was dissolved with 6 mol/L hydrochloric acid,staying overnight under 110 ℃ acid solution after full of nitrogen,then evaporated with a stream of nitrogen to near dryness and redissolved with water.The LC separation was performed on a Phenomenex Kinetex PFP column with 5 mmol/L ammonium acetate solution and methanol as mobile phases by gradient elution.The tyrosine isomers were determined by MS/MS in negative electrospray ionization（ESI） mode,and quantified by the matrix-matched（MRM） external standard method.Good separations were obtained between the tyrosine isomers and other impurity peaks .In 0.005-1.0 mg/L concentration range,the peak areas of tyrosine isomers against concentration showed good linear relationships with correlation coefficient（r2）more than 0.999.The average recoveries of tyrosine isomers in protein-containing function food at three spiked concentration levels ranged from 81.8% to 98.2%,with relative standard deviations（RSDs,n=6） less than 8.0%.The limit of quantitation（LOQs） were 5.0 μg/kg and 8.0 μg/kg,and the limits of detection（LODs） were 1.5 μg/kg and 2.4 μg/kg,respectively.This method was applied in real samples,and the result indicated that the radiation dose could be quantitatively evaluated by the linear correlation with coefficients of determination（r2） more than 0.98 in individual irradiated protein containing function food samples.The method could be applied in qualitative identification of tyrosine isomers in protein-containing functional food.关键词：protein-containing functional food;o-tyrosine;m-tyrosine;liquid chromatography-tandem mass spectrometry
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- 1153
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- 2
发布时间： - 摘要：A novel method for the determination of copper 8-quinolinolate by ultra-performance liquid chromatography（UPLC） was developed.The sample was extracted with 4% acetic acid solution and cleaned up with a Cleanert PCX cartridge.The cartridge was eluted with 1% ammonium acetate-methanol.The elution was evaporated to near dryness under a stream of nitrogen,and dissolved by mobile phase.The target compound was separated on a Vneusil MP C18 column（150 mm×4.6 mm，5 μm） using 0.1% TFA-acetonitrile（95∶5） as mobile phase.The method had a good linear correlation（r≥0.999 9 ）in the range of 0.05-10 μg／mL.The average recoveries of copper 8-quinolinolate at a spiked range of 0.05-2.0 mg／kg were in the range of 72.3%-84.1% with relative standard deviations（RSDs）of 2.1%-3.8%.The limit of detection（LOD） was 0.024 mg／kg.关键词：copper 8-quinolinolate;ultra-performance liquid chromatography（UPLC）;watermelon;residues
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- 8
发布时间： - 摘要：Two methods,gas chromatography-mass spectrometry（GC-MS） and liquid chromatography-tandem mass spectrometry（LC-MS/MS） were proposed for the study on the trace components in tainted starch noodles（fake starch noodles） and noodles made from real sweet potato.Some impurities such as phenol and pyrrolo［1,2a］pyrazine-1,4-dione,hexahydro-six were detected by GC-MS,and tartrazine,sunset yellow and brilliant blue were found by LC-MS/MS,while such components would not exist in real sweet potato.The existence of these substances could be used to confirm weather starch noodles were tainted or not.关键词：tainted starch noodles;feature components;GC-MS;LC-MS/MS
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- 941
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- 1
发布时间： - 摘要：An in-situ polymerization method was used in the preparation of a novel solid-phase microextraction（SPME） coating，where butyl methacrylate-ethylene glycol dimethacrylate（BMA-EDMA） was directly bonded to the surface of a modified stainless steel wire．Coupled with high performance liquid chromatography（HPLC），the prepared coating was applied in the extraction and determination of sudan Ⅰ,Ⅱ,Ⅲ dyes in fermented bean curd．The experimental conditions for SPME，including extraction time，desorption time and salt concentration were optimized．As a result,the linear relationships（r2≥0.923 2） between concentrations of 50 μg/L and 1 000 μg/L for sudan Ⅰ,Ⅱ,Ⅲ dyes were obtained.The limits of detection ranged from 0.303 μg/L to 1.808 μg/L．the run-to-run（n=3） and fiber-to-fiber（n=6） relative standard deviations of this method were no more than 9.2% and 16.5%,respectively.The spiked recoveries of three dyes were in the range of 79.5%-86.4%.The prepared stainless steel fiber possessed some advantages including high mechanical strength,simplicity,good stability and low cost.The method was fast and sensitive,and was suitable for the determination of sudan dyes in fermented bean curd.关键词：solid-phase microextraction;high performance liquid chromatography;stainless steel wire;sudan dyes
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发布时间： - 摘要：Protein phosphorylation is one of the most important post-translational modifications,and also plays a vital role in cellular metabolism.Aberrant protein phosphorylation states and kinase activity are associated with many human diseases such as cancer,diabetes mellitus and heart disease.Due to the dynamic reversibility of protein phosphorylation and the low abundance of phosphoprotein/phosphopeptide in biological samples,it is a big challenge to the ultrasensitive detection of protein phosphorylation,which is most significant for earlier clinical analysis on disease and drug screening.In this work,the mechanism for selective recognization or capture of phosphoprotein/phosphopeptide was discussed.The main mechanisms for enrichment of phosphoprotein/phosphopeptide or signal amplification in protein phosphorylation analysis based on nanostructured materials were introduced in detail.Based on that mechanism,the recent application and development of nanostructured materials in protein phosphorylation analysis were reviewed.关键词：nanostructured materials;protein phosphorylation;enrichment of phosphopeptide;signal amplification;development
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发布时间： - 摘要：The EU Toy Safety Directive which came into force in 2013 has substaintially increased requirements on chemical substances.Restricted migration elements have been increased from 8 to 19 elements,which include trivalent chromium,hexavalent chromium and organotin.Restricted migration amount of N-nitrosamines and restriction of allergenic fragrances have been added.The limited amounts of lead,cadmium,hexavalent chromium,organotin have been decreased to 3.4,0.5,0.005,0.2 mg/kg respectively,and traditional toy testing methods such as inductively coupled plasma-optical emission spectrometry and gas chromatography-mass spectrometry cannot satisfy the testing requirements of hexavalent chromium,organotin,N nitrosamines and fragrances.This paper has briefly described the chemical requirements of TSD and corresponding testing methods,highlighted the technical progress and difficulties of testing methods of hexavalent chromium and organotin.关键词：toy;EU Toy Safety Directive;hexavalent chromium;organotin;N-nitrosamines
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