最新刊期
卷 35 ， 期 10 ， 2016
- 摘要：In this study，Bt-transgenic and parental rice from two places(Wuhan and Hainan) was analyzed using gas chromatography-mass spectrometry-based metabolomics.774 chromatographic peaks were detected using GC-TOF/MS.Among them，278 metabolites，including carbohydrates，amino acids，fatty acids，organic acids and other compounds，were identified.The results showed that the difference of metabolome was not significant between the Bt-transgenic and parental rice using the principal component analysis method.Further partial least squares discriminant analysis，only two concentrations of glycerol and rhamnose were changed between Bt-transgenic and parental rice,rising 1.55 times and 3.32 times, respectively, compared to that of parental rice. The factor of producing origins of rice was investigated.15 metabolites have significant between two origins rice from Wuhan and Hainan. GC-TOF/MS-based metabolomic method was successfully used in comparative analysis of Bt-transgenic and parental rice,which suggested that it has no significant effect to transform exogenous Bt gene into rice cells，and the factor of rice producing origin is more noticeable.关键词：genetically modified rice;metabolomics;differential metabolites;multivariate statistical analysis;GC-TOF/MS
- 1774
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- 1056
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发布时间： - 摘要：The study aims to illustrate the effect of diphenylheptane A on the glycerophospholipids metabolism in the inflammatory process through analyzing glycerophospholipids components of RAW264.7 cells under different status(control，inflammation，administration) and screening potential pathological and pharmacological biomarkers.RAW264.7 cells were randomly divided into four groups：control group(C)，inflammation group(L)，diphenylheptane A(D)，ibuprofen(B，positive control).C and L were treated with fresh medium while D and B were treated with medium containing 20μg/mL diphenylheptane A or 100μg/mL ibuprofen，respectively.1 h later，lipopolysaccharide(LPS) was added to L，D and B at a final concentration of 0.5μg/mL.24 h later，glycerophospholipids in RAW264.7 cells of four groups were extracted by modified Bligh-Dyer method and analyzed by ultra performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry(UPLC-Q/TOF MS) in both positive and negative ion modes.Then，glycerophospholipids components were identified by combination of MS/MS fragment ions information，element composition in MassLynx 4.1 and the Lipid Maps database.Finally，potential pathological and pharmacological biomarkers were screened by unsupervised principal component analysis(PCA)，supervised partial least squares-discriminate analysis(PLS-DA)，supervised orthogonal partial least squares discriminate analysis(OPLS-DA)，and Student’s t-test(P<0.05).The results showed that 27 potential pathological biomarkers were found by comparing C and L，23 potential pharmacological biomarkers were found by comparing D and L，and 17 potential pharmacological biomarkers were found by comparing B and L.The biomarkers mainly included phosphatidylcholine(PC)，lysophosphatidylcholine(lysoPC)，phosphatidylethanolamine(PE) and lysophosphatidylethanolamine(lysoPE).It was found that diphenylheptane A led to obvious changes of glycerophospholipids metabolism during the process of inflammation，which were closely related to the occurrence and development of inflammation.关键词：inflammation;glycerophospholipids;diphenylheptane A;ibuprofen;biomakers;ultra performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry(UPLC-Q/TOF MS)
- 2007
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- 1081
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- 2
发布时间： - 摘要：A method based on microwave-assisted extraction combined with liquid chromatography-tandem mass spectrometry(MAE/LC-MS/MS) was established for the simultaneous determination of 14 antipsychotic and sedative substances in human nails.About 20 mg of decontaminated and pulverized nail samples was microwave-assistedly extracted for twice in the presence of clozapine-d4 used as the internal standard, and the supernatant was determined by LC-MS/MS using the Allure PFPP column with a mobile phase of methanol(containing 20mmol/L ammonium acetate)-20mmol/L ammonium acetate buffer. Multiple reaction monitoring(MRM) mode was used to analyze 14 antipsychotic and sedative substances. Good linearities(r2≥0.990) over the corresponding range were obtained for all the analytes.The limits of detection(LOD) were in the range of 0.1-50pg/mg and the limits of quantitation(LOQ) were 100pg/mg for most of the analytes.The deviations of intra- and inter-RSD were not more than 7.8%.Accuracies were within ±10.16%.Positive results were obtained from 7 authentic nail samples,which were in good accordance with the drug administration of the corresponding antipsychotic and sedative substances.The developed method presents a simplified,efficient and rapid procedure for sample preparation,and shows high sensitivity and selectivity,which is suitable for the simultaneous analysis of 14 antipsychotic and sedative substances at pg/mg levels in nail samples.关键词：microwave-assisted extraction(MAE);liquid chromatography-tandem mass spectrometry(LC-MS/MS);nails;antipsychotic and sedative substances
- 2453
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- 1129
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- 3
发布时间： - 摘要：A gas chromatography-tandem mass spectrometric(GC-MS/MS) method was developed for the determination of 6 plant growth regulators(PGRs),including 4-CPA,2,4-D,NAA,IAA,2,4-D butyl ester and IBA in bean sprout and tomato.The sample was firstly extracted with acided acetonitrile.The extract was concentrated and redissovled with methanol.And then, the solution was methyl esterified with 14% boron trifluoride methanol solution.The esterified solution was extracted with ethyl acetate-hexane(2∶8,by volume) after adding 2,4-D butyl ester solution.The treated extract was determined by GC-MS/MS under multiple reaction monitoring(MRM) mode,and quantified by the external standard method.The limits of quantitation(S/N>10) of 6 PGRs in bean sprout and tomato were 15μg/kg.The recoveries of PGRs in bean sprout and tomato at three spiked levels of 15,30,60μg/kg ranged from 70.0% to 127% with relative standard deviations(RSDs) of 4.1%-11.4%.The developed method is easy, fast and accurate,and could be applied in routine test of plant growth regulators in bean sprout and tomato samples.关键词：bean sprout;tomato;plant growth regulator;gas chromatography-tandem mass spectrometry(GC-MS/MS)
- 1990
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- 1157
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- 12
发布时间： - 摘要：Currently existing national standards for honey adulteration are based on one type or certain types of compounds.Therefore,it is necessary to develop a multi-component and multi-index method to identify the honey adulteration.In this research,the changes of fingerprint between pure and adulterated honey were explored based on the NMR fingerprinting analysis and chemometrics method.Unsupervised method of principal component analysis（PCA）,supervised method of partial least squares discriminant analysis（PLS-DA） and orthogonal-PLS-DA（OPLS-DA） were all used to extract the useful information from NMR signals.The results showed that OPLS-DA model could distinguish the adulterated honey from pure honey.The explanation abilities based on the OPLS-DA model was 90.5%.The prediction and recognition abilities were 75.5% and 89.7%，respectively.Through permutation test,the chemometric model showed good stability,accurate predictability and high reliability.Several significant markers were found to distinguish honey from the loading plot and correlation coefficient analysis of OPLS-DA model.Combined with the correlation coefficient analysis,multiple linear regression equation was established to distinguish the adulterated honey from pure honey.The proposed method was simple and sensitive.This method provided an effective approach to control the honey quality and detect the honey adulteration.关键词：nuclear magnetic resonance technology(NMR);chemometrics method;pattern recognition technology;honey adulteration
- 2043
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- 1005
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- 6
发布时间： - 摘要：A simple and rapid method was established for the preconcentration and determination of 13 sulfonamide residues in water samples by ultrasonic-assisted dispersive liquid-liquid microextraction(UA-DLLME) coupled with ultra performance liquid chromatography-tandem quadrupole mass spectrometry(UPLC-MS/MS)．The target compounds in water samples were synergistically extracted in ultrasonic dispersed mode and separated on a C18(100 mm×2.1 mm,1.7 μm) column with acetonitrile-0.1% formic acid solution as mobile phase，and determined by UPLC-MS/MS under multiple reactions monitoring(MRM) mode．The kind and dosage of extraction agent and dispersing agent，extraction time，dosage of sodium chloride and pH conditions were optimized．Under the optimized conditions，the calibration curves of 13 sulfonamides were linear in the certain concentration range with correlation coefficients greater than 0.998.The detection limits of the method(S/N＝3) were between 0.6 ng/L and 2.4 ng/L.The average recoveries of sulfonamides at three spiked levels in water sample ranged from 80.3%to 101.8%with relative standard deviations(RSD，n＝5) of 0.7%-4.5%.The developed method was simple，environment-friendly and sensitive,and was suitable for the determination of multiple sulfonamide residues in water.关键词：ultrasonic assisted dispersive liquid-liquid microextraction(UA-DLLME);ultra performance liquid chromatography coupled with tandem quadrupole mass spectrometry(UPLC-MS/MS);sulfonamide;water
- 1962
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- 1091
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- 9
发布时间： - 摘要：A new approach was established for the simultaneous determination of 29 restricted drugs,including quinolones,sulfoamides,trimethoprim,tetracyclines,lincosamides,macrolides in urine of swine supplied to Hong Kong by high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS).The analytes were extracted with ammonium acetate and EDTA buffer,and followed by cleanup using an HLB solid phase extraction cartridge.The sample matrix-matched calibration was used to determine the residue.Electrospray ionization mass spectrometry was operated in the positive mode. The analysis of 29 restricted drugs was achieved under the multiple reaction monitoring(MRM) mode.The results indicated that correlation coefficients of the calibration curves were more than 0.99.The average recoveries of 29 analytes at three spiked concentration levels ranged from 58% to 108%.The intra-day relative standard deviations(RSDs) were in the range of 1.9%-18.9%,and the inter.day RSDs were 3.4%-20.9%.The limits of quantitations(LOQs,S/N≥10) were in the range of 1.0-10.0 μg/L.The method is economic,high efficient and reliable,and is suitable for the simultaneous determination of multiple residues of veterinary drugs in swine urine．关键词：high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS);swine urine;restricted drug;multiple residues
- 1952
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- 1244
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- 2
发布时间： - 摘要：A method of gas chromatography(GC) coupled with solid phase extraction was established for the simultaneous determination of 8 kinds of organophosphorus pesticide residues，including ethopropophos,sulfotep,terbufos,monocrotophos,parathion methyl,fenitrothion,isofenphos methyl and isocarbophos in xinhui dried orange peel and its products.The factors affecting extraction，purification and detection efficiency were optimized，and the optimal conditions were as follows：the samples were extracted with ethyl acetate，and purified on a homemade double solid phase extraction column packed with N-propylethylenediamine and multi-walled carbon nanotubes.The separation of target compounds were performed on a film thickness of Shimadzu Rtx-1701 capillary column(30 m×0.25 mm×0.25 μm)，and the quantitative analysis of organophosphorus pesticides was carried out by GC with flame photometric detector and the external standard method.Under the optimized conditions，the calibration curves of 8 organophosphorus pesticides were linear in the range of 0.020-1.0 μg/mL with correlation coefficients of 0.997 0-0.999 2．The detection limits(S/N=3)were in the range of 3.6-8.8 μg/kg．The recoveries of the pesticides in Xinhui dried orange peel and its products at three spiked levels ranged from 72.5%to 106%，with relative standard deviations of 2.8%-8.7%. With the advantages of accuracy,sensitivity，easy operation and rapidness,the method is applicable in the simultaneous determination of 8 kinds of organophosphorus pesticides in Xinhui dried orange peel and its products.The homemade column is worthy of popularization and application as it is inexpensive,and could largely reduce the detection cost.关键词：organophosphorus pesticides;pesticide residues;homemade double solid phase extraction column;gas chromatography(GC);xinhui dried orange peel
- 1921
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- 1114
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- 6
发布时间： - 摘要：A new method using TurboFlow online cleanup combined with tandem mass spectrometry was developed for the rapid and simultaneous determination of six polyether antibiotics residues,e.g.lasalocid,salinomicin,monensin,narasin,maduramycin and nigericin in animal-originated foods of animal origin.The milk，chicken and egg samples were extracted with acetonitrile，and the extracts were purified on a Cyclone-p column.After being eluted from the clean-up column，the analytes were separated on a Thermo Scientific Hypersil-Gold C8(150 mm×2.1 mm，5 μm) column and detected by electrospray mass spectrometry in positive ionization mode with multiple reaction monitoring.Under the optimized conditions，the linear ranges of six polyether antibiotics were in the range of 1-100 μg/L with correlation coefficients higher than 0.999.The limits of quantitation(LOQ) for all samples were 1 μg/kg.The recoveries from milk，chicken and egg samples were in the range of 71.9%-109.0% with relative standard deviations of 1.5%-14.9%.关键词：TurboFlow on-line cleanup;liquid chromatography-tandem mass spectrometry;polyether antibiotics;animal-originated foodstuffs
- 1962
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- 1127
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- 1
发布时间： - 摘要：A molecularly imprinted solid phase extraction coupled with ultra high performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method was developed for the determination of eleven beta blocker residues in animal derived foods.The sample was enzymed with β-glucuronidase/aryl sulfatase.The supernatant fraction was adjusted to the optimal pH value，and then extracted with isopropanol-ethyl acetate (5∶5，by volume).The organic solvent was first evaporated to dryness, and then redissolved，finally purified by molecularly imprinted solid phase extraction.The analyte was separated with a BEH C18 column by gradient elution using methanol-5 mmol/L ammonium acetate (containing 0.1% formic acid) as mobile phase，and detected by MS under ESI+ ionization and multiple reactions monitoring mode.The quantification of the analytes was performed by the matrix standard addition method.The limits of detection and limits of quantitation were in the ranges of 0.02-0.1 μg/kg and 0.05-0.25 μg/kg，respectively.The calibration curves of 11 β-blockers were linear in the range of 0.05- 10 μg/kg，with correlation coefficients not less than 0.991.Under three spiked levels，the average recoveries of the analytes in pork and liver were 73.2%-108.3% and 70.2%-98.2%，respectively，with relative standard deviations of 1.3%-9.5% and 3.7%-9.8%，respectively.The method is rapid，sensitive and precise，and is suitable for the determination of β-blocker multi residues in animal derived foods.关键词：molecularly imprinted solid phase extraction;liquid chromatography-tandem mass spectrometry (LC-MS/MS);β-blocker;residue determination
- 2377
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- 1034
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- 3
发布时间： - 摘要：The optimum reducing sugar determination conditions of 3,5-dinitrosalicylic acid colorimetry(DNS colorimetry) were investigated using the Response Surface Method(RSM).The reducing sugar content in apple was obtained under the optimum extraction conditions.Based on the results of the single factor experiments，an optimization procedure was carried out in order to investigate the effects of key parameters on reducing sugar determination.Optimization was conducted using a Central Composite Design(CCD) with three key factors of DNS amount，reaction temperature and coloration time.The quadratic term model of the determination conditions was established and the reliability was checked.The results of regression analysis presented a non-significant lack of fit(P=0.133 7) and a high coefficient of determination value(R2) of 0.957 4 for the response surface model,which showed a satisfactory agreement of the polynomial regression equation with experimental data.The influence of three factors followed the sequence as：DNS amount > reaction temperature > coloration time.The optimum determination conditions of reducing sugar using DNS colorimetry were DNS amount：4.0 mL，coloration time：5.0 min，reaction temperature：87.0 ℃.The actual concentration of reducing sugar was obtained to be 94.66 mg/L,which was consistent with the theory predicts under the optimal conditions.According to the optimum determination conditions，the precision，repeatability and accuracy of the method were verified using apple，peach，grape，hami melon，navel orange and pineapple as representative fruits.The standard deviations，relative standard deviations and recoveries of the reducing sugar contents in the 6 fruit species were in the range of 0.1%–0.5%，2.0%–4.8%，90.6%–104.2%，respectively.The study provided a reliable method for accurate，efficient and cost-effective detection of reducing sugar contents in fruits.关键词：reducing sugar;response surface methodology(RSM);3,5-dinitrosalicylic acid(DNS) colorimetry;optimization;fruit
- 2227
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- 997
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- 20
发布时间： - 摘要：In this paper，prussian blue(PB) coated gold nanoparticles(Au NPs) were firstly prepared by in situ method.Then，polydopamine(PDA) wrapped Au-PB was synthesized based on the characteristic of one-step oxidative polymerization of dopamine.The bioinspired surface enriched amino and hydroxyl groups were further used as a support to anchor active platinum nanoparticles(Pt NPs).Horseradish peroxidase(HRP) functionalized Au-PB-PDA-Pt nanocomposites was also used for the fabrication of H2O2 biosensor.By taking advantages of the excellent biocompatibility and film forming ability of PDA，the large surface area and high biocompatibility of Pt NPs，and the synergistic employ of PB，Pt and HRP，the HRP functionalized nanocomposites modified electrode exhibited an excellent electroreduction activity to H2O2.Under the optimum conditions，the linear detection range from 2.0×10-7-1.0×10-3 mol?L-1 was observed,and a detection limit was 1.2×10-7 mol?L-1.关键词：H2O2 sensor;nanocomposites;prussia blue;polydopamine;horseradish peroxidase
- 1740
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- 957
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- 1
发布时间： - 摘要：A technique for the analysis of the meat fatty acid was established,and through the analysis of the content,type and characteristic fragment fingerprint of the fatty acid,the identification method of the pig-derived conponents based on differences of fatty acids were realized.A large number of meat products were determined by gas chromatography(GC),and 35 kinds of fatty acids were identified by retention time and mass spectrometry.The differences of different fatty acids were determined by selecting 18 kinds of the fatty acids which are more stable for statistical analysis.Combined with feature maps,8 kinds of fatty acids were used in the identification of pig-derived conponents in meat.According to this method,it can be determined whether the meat products contain pig-derived conponents.This method is simple,rapid,low cost and high discriminable,and has a certain application prospect in the identification of pork.关键词：fatty acid;pork;identification;gas chromatography(GC)
- 1767
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- 925
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- 1
发布时间： - 摘要：Using 3-mercaptopropionic acid(MPA) as surface modifiers,Mn doped ZnS quantum dots with stable and good optical properties were synthesized via water phase method.In phosphate-buffered saline solution,the addition of promethazine could obviously quench the room temperature phosphorescence of MPA-capped Mn-doped ZnS quantum dots.Thus,a new method for the detection of promethazine was established.The quenched phosphorescence intensity(ΔRTP) was linearly proportional to concentration of promethazine.The linear ranges of promethazine were 3.2-32 μmol/L and 32-160 μmol/L,with correlation coefficients of 0.998 and 0.999,respectively.The limit of detection for the method was 0.553 μmol/L.This method was used to detect promethazine in human serum and urine samples with satisfactory results,and the recoveries ranged from 96.4%to 103.1%.关键词：MPA-capped Mn-doped ZnS;quantum dots(QDs);room temperature phosphorescence(RTP);promethazine(PMZ)
- 1785
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- 962
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- 3
发布时间： - 摘要：The di-O-methylcurcumin L as a molecular probe was directly synthesized by using curcumin and iodomethane.The title compound was characterized by X-ray single-crystal diffraction,1H NMR，13C NMR and ESI-MS.The crystal structure of the compound belongs to monoclinic system with a space group of C2/c.The cell parameters were as follows：a=22.317(6) nm,b=8.703 8(19) nm，c=23.039(5) nm，β=93.378(10) °，V=4 467.4(18) nm3，Z=4，Dc=1.206 g?cm-3，F(000)=1 720，μ(MoKα)=0.088 mm-1，R=0.080 9，ωR=0.216 3.The probe L exhibited a selective and sensitive absorption response toward Fe3+ over a wide range of metal ions in ethanol-water solution(9∶1，Tris-HCl buffer，pH 7.2).The results of ultraviolet titration and mass spectrometry showed that the probe L and Fe3+ formed a 1∶1 complex,and the association constant K was determined to be 1.089×106 L/mol.The mothod showed good linearity(r2= 0.997 8) for Fe3+ concontration in the range of 5.5×10-6– 3×10-5 mol/L with a limit of detection of 2.2×10-6 mol/L.关键词：di-O-methylcurcumin;molecular probe;Fe3+ ion;recognition;ultraviolet spectra
- 1814
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- 910
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- 3
发布时间： - 摘要：An ultrasonic extraction-solid phase extraction-reversed phase high performance liquid chromatographic method was developed to determine sulfonamides and tetracyclines antibiotics in surface sediments by optimizing condition of pretreatment.The sediment samples were extracted with a mixture of methanol-EDTA/McIlvaine buffer(1∶1) under ultrasonication after freeze-dried,then blowed at 40 ℃ under nitrogen to remove the organic solvent.After purified with a Poly-Sery HLB solid-phase extraction cartridge,the extract was determined with ODS-P C18 column and UV-detector.The results showed that the calibration curves of 7 sulfonamides were linear(r2>0.999) in the concentration range of 0.025-0.5 mg/L,and the recoveries of three spiked levels ranged from 71.4% to 107.6% with relative standard deviations(RSDs,n=3) of 14%-52%.The method detection limits(MDL) ranged from 0.07 ng/g to 0.29 ng/g.The calibration curves of 3 tetracyclines were linear(r2>0.999) in the concentration range of 0.05-1 mg/L,the recoveries at three spiked levels ranged from 62.2% to 87.9%,with RSDs(n=3) of 1.1%-4.6%,and the method detection limits(MDL) were in the range of 0.45-0.58 ng/g.The developed method was applied to analyze the surface sediments of an urban lake and its inflowing rivers,in which 10 kinds of target antibiotics were all detected.The results showed that the method was simple,rapid and accurate,and was suitable to determine the sulfonamides and tetracyclines antibiotics in the sediments.关键词：surface sediment;reversed phase high performance liquid chromatography(RP-HPLC);solid-phase extraction;antibiotics;sulfonamides;tetracyclines
- 1869
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- 990
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- 3
发布时间： - 摘要：A method of high performance liquid chromatography(HPLC) with fluorescence detector(FLD) was developed for the simultaneous determination of 5 substances in the microbial enzymatic reaction system of L-alanyl-L-glutamine,including L-alanyl-L-glutamine,L-glutamine,L-alanine methyl ester,L-glutamic acid and L-alanyl-L-alanine.Standard substances and samples were derivated with phthaldialdehyde(OPA) by online automated precolumn derivatization.The analytes were separated on a C18 column using acetonitrile(12%) and 12.5 mmol/L potassium phosphate buffer(88%,pH 7.4) as mobile phase by isocratic elution and analyzed quantitatively by the external standard method at an excitation wavelength of 338 nm and an emission wavelength of 450 nm.The flow rate was set at 1 mL/min and the column temperature was 40 ℃.The calibration curves for five standard substances were all linear in a broad range with correlation coefficients more than 0.999 4.The average recoveries of five substances at three spiked levels ranged from 93.5% to 104.9% with relative standard deviations(RSDs) less than 7%.Injecting six times every two hours one day,the RSD values of retention time for five substances were all less than 0.12%,and the RSD values of peak area of five substances were all less than 1.2%.The method was simple,sensitive,accurate and repeatable with a high resolution.关键词：high performance liquid chromatography(HPLC);online automated precolumn derivatization;the reaction system of L-alanyl-L-glutamine;sample preparation
- 1845
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- 971
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- 1
发布时间： - 摘要：A kind of porphyrin-spiropyrane derivative was synthesized and detailedly characterized.On this basis,the photoisomerization and ionic response behaviors of the compound were studied by UV-Vis spectrometry,and a new mechanism to explain the coupling behavior between porphyrin ring and spiropyrane was proposed.The experiental results showed that metal ions could induce porphyrin-spiropyran molecule to generate a new conformation which will affect the photoisomerization properties of spiropyrane.In addition,with the changes of ionic radius and electrophilic ability,the optical properties of the porphyrin-spiropyrane derivative presented significant differences.This study provides an idea for constructing a new ionic probe.关键词：spiropyrane;porphyrin;photoisomerization;ionic response
- 1792
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- 882
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- 1
发布时间： - 摘要：An ultra-performance liquid chromatography-tandem mass spectrometric(UPLC-MS/MS) method was developed for the analysis of three triphenylmethane bactericides in sediment by accelerated solvent extraction(ASE).The analytes were extracted from the dispersed samples with neutral alumina by ASE using acetonitrile-McIlvaine buffer(10∶2，by volume) as solution.The extract were analyzed by UPLC-MS/MS in multiple-reaction monitoring(MRM) mode,quantified by the internal standardization.The calibration curves of three triphenylmethane dyes were linear in the range of 0.5-50.0 μg/L with correlation coefficients more than 0998.Under the optimal extraction conditions of 60 ℃ temperature and 1 500 psi pressure,the recoveries of three compounds ranged from 65.8% to 112%,with RSDs(n=6) of 5.1%-14.4%.The limits of detection and quantitation were in the range of 0.006-0.007 μg/kg and 0.024-0.028 μg/kg,respectively.The method was successfully used to detect the sediment samples from Gehu Lake.关键词：triphenylmethane;ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS);accelerated solvent extraction(ASE);sediment
- 1886
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- 1075
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- 1
发布时间： - 摘要：Rapid determination of CH4，C2H4，C3H6 contents in cracked gas could help grasp the reaction depth in ethylene cracking furnaces and optimize process operations.The most commonly used analytical methods for cracked gas is gas chromatography(GC).Through multiple valves，columns and detectors，full components quantitative information is available by GC.But this takes a long period for analysis，which means 20 min between 2 tests.In contrast，the established laser Raman spectroscopy for 6 main components(H2，CH4，C2H4，C2H6，C3H6 and C3H8) in cracked gas can shorten the analytical time to nearly 2 min.In the meantime，Raman analysis method consumes no cost of carrier gases or chromatographic columns，and sharply cuts the analytical cost.It utilizes concentration curves for quantitative analysis of 6 single component,using 3 times of signal to noise ratio(3 S/N) to correct the cross interferences for quantitative analysis of 6 component in mix gas.In the quantitative analysis of gas mixture，it has a good measurement accuracy in the quantitative analysis of H2，C2H4，C3H6 and C3H8，with relative errors smaller than 2%.But the measurement accuracy on CH4 and C2H6 by Raman analysis method needs to be improved，which means the established Raman analysis method needs further optimization.关键词：laser Raman spectroscopy;gas analysis;cracked gas;gaseous hydrocarbons
- 1917
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- 1018
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- 1
发布时间： - 摘要：A novel method was established to separate and purify alkaloids from Cynoglossum amabile Stapf et Drumm with cation exchange resin(CER) coupled with macroporous adsorption resin(MAR) based on dynamic tests.The result indicated that the alkaloids extracted were eluted with water and NaCl through CER and twice with ether and 50%ethanol through MAR,then the purities of heliotrine and lasiocarpine were up to 81.6%and 79.2% from 0.73%and 2.2%,respectively.Extraction yields were up to 50.6 mg/g and 92.7 mg/g from 4.6 mg/g and 10.7 mg/g,respectively.The method has the advantages of low cost,low pollution,short cycle，high efficiency and simple operation,and is suitable for popularization in industry production.关键词：cation exchange resin;macroporous adsorption resin;Cynoglossum amabile Stapf et Drumm alkaloid;heliotrine;lasiocarpine;separation;purification
- 1768
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- 952
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- 2
发布时间： - 摘要：A new analytical method was developed for the determination of melamine in milk powder by solid-phase extraction coupled with surface-enhanced Raman spectroscopy.The melamine in sample was extracted with acetonitrile,then adsorbed with activated carbon and eluted with sodium hydroxide solution.The results showed that the linear range for melamine was in the range of 0.005 0-1.6 mg/L,with a limit of detection of 0.100 mg/kg.While the method was applied in the analysis of melamine in milk powder,the recoveries for melamine were in the range of 75.3%-125%,and the relative standard deviations(n=5) were not more than 9.3%.With a remarkable effect in removing impurities,this method is accurate,reliable and sensitive in the rapid determination of melamine in milk powder,showing a great potential in monitoring the quality of milk powder.关键词：surface-enhanced Raman spectroscopy;solid-phase extraction;milk powder;melamine
- 1931
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- 931
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- 5
发布时间： - 摘要：An optimized chemical separation and purification method for measuring Cu and Zn isotopic composition in cobalt-rich crusts was established.A new type of anion exchange resin，AG MP-1M，was successfully applied in the chemical separation of Cu，Co，Fe and Zn from cobalt-rich crusts.Cu，Co，Fe and Zn were separated using 8.2 mol/L HCl+0.01% HF+0.001% H2O2，2 mol/L HCl+0.001% H2O2 and 0.5 mol/L HNO3 as eluents.The recoveries for Cu and Zn were both close to 100%.No mass fractionation during the chemical separation procedure was observed.This method could be applied in the separation of Cu and Zn in Co-rich crusts for high-precision isotope analysis using MC-ICP MS.关键词：cobalt-rich crusts;MC-ICP MS;Cu isotopes;Zn isotopes
- 1813
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- 995
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发布时间： - 摘要：The horseradish peroxidase(HRP) was fixed on the surface of glassy carbon electrode(GCE) modified by chitosan(CTS)-carboxylic multi-walled carbon nanotubes(MWNTs).The modified electrode thus prepared was named abbreviately as HRP-CTS/C-MWNTs/GCE.The HRP imbedded in the complex was characterized by fourier transform infrared spectrometry.The result indicated that its composition had no change.The electrochemical property of HRP-CTS/C-MWNTs/GCE was studied by cyclic voltammetry.It was found that the modified electrode exhibited an excellent electrocatalytic response toward the reduction of H2O2.In 1/15 mol?L-1 PBS(pH 6.98) buffer solution， a pair of redox peaks were observed,and a good linear relationship(r=0.998 6) between values of reduction peak current and H2O2 concentration was obtained in the range of 0.1-12 mmol?L-1.The method was applied in the detection of hydrogen peroxide the commercially available medical hydrogen peroxide，with content of 2.93%关键词：chitosan;carboxylic carbon nanotube;horseradish peroxidase;electrochemical sensor;hydrogen peroxide
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发布时间： - 摘要：Consulting the indirect comparison protocol of Standard Reference Photometer（SRP) from BIPM(Bureau International des Poids et Mesures) and U.S.EPA（Environmental Protection Agency),the indirect comparison technique of SRPs was developed by preparation of pre-comparison,confirmation of comparison procedure,treatment of comparison results and evaluation of comparison index through the ozone transfer standard.Furthermore,SRPⅠand SRPⅡ were indirectly compared,while the slopes of the two indirect comparison equations between SRPⅠand SRPⅡ were 1.003 26 and 1.003 58 with the intercepts of 0.109 05 nmol/mol and 0.080 99 nmol/mol,respectively,which indicated that there was a good consistency between the two SRPs,and the indirect comparison results could meet the comparison index of SRPs by U.S.EPA.The indirect comparison method of SRPs was established,and it was suitable for the comparison between SRPs.关键词：ozone;standard reference photometer;indirect comparison;technique
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发布时间： - 摘要：DNA based biosensors have become increasingly important in hazardous and toxic substances detection.Particularly,the aptamer-based methods have been intensively investigated as potential analytical tools providing desired portability,fast response,high sensitivity and specificity in addition to lower cost against classical methods.Some of the techniques for detection of aptasensors(including colorimetric,fluorescent and electrochemical assays) in the last few years were summarized,and their detection characters and applications were discussed.
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