最新刊期
卷 30 ， 期 12 ， 2011
- 摘要：A multi-residue method was developed for the simultaneous determination of 8 estrogens,5 androgens,6 progesterones,8 glucocorticoids and 3 chloramphenicols in fish using QuEChERS sample preparation and liquid chromatography-tandem mass spectrometry（LC-MS/MS）.The homogenized sample was dispersed by water,then the analytes were extracted with acetonitrile.The separation were performed on a ZORBAX Extend-C18 column（100 mm×2.1 mm，3.5 μm） by gradient elution after dispersive-solid-phase extraction（d-SPE） purification.The qualitative and quantitative analysis of 30 analytes were operated by electrospray ionization mass spectrometry under the positive or negative mode using multiple reaction monitoring（MRM）.Acetonitrile and water were used as the mobile phase in the positive mode.Acetonitrile and 0.1% ammonia hydroxide were used as the mobile phase in the negative mode.The correlation coefficients of calibration curves were over 0.99 in the corresponding concentration range.The average recoveries of the 30 analytes at three spiked concentration levels varied from 63% to 118% with relative standard deviations（RSDs） of 3.8%-18.2%.The limits of detection（LOD,S/N≥3） and quantitation（LOQ,S/N≥10） were 0.03-1.6 μg/kg and 0.1-5.0 μg/kg,respectively.The real sample tests showed that the proposed method was simple,rapid,sensitive,reliable and cost-effective,and was suitable for the simultaneous determination of hormones and chloramphenicols in fish samples.关键词：QuEChERS;liquid chromatography-tandem mass spectrometry（LC-MS/MS）;estrogens;androgens;progesterones;glucocorticoids;chloramphenicols;fish
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- 3
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- 47
发布时间： - 摘要：An ultra performance liquid chromatography-tandem mass spectrometric（UPLC/TUV-MS/MS） method was developed for the determination and validation of laccaic acids in juice.The juice samples were cleaned by solid-phase extraction technique with Oasis? HLB cartridge.The targeted compounds were separated on a Waters Acquity UPLC BEH Shield RP C18 column with acetontrile-0.1% formic acid as mobile phase by gradient elution,and detected with TUV detector at 286 nm.A quadrupole mass spectrometer with atmospheric electrospray ionization source was used for the identification under SIR mode and the collision induced dissociation analysis.The external standard method was used for quantitation analysis.It was found that the lac dye extract consisted of laccaic A,laccaic B,laccaic C and laccaic E,of which the relative contents were 57.95%,31.33%,6.12% and 2.96%,respectively,based on the area normalization method,and the calibration curves for four laccaic acids showed good linearities in the range of 0.029-11 mg/L with correlation coefficients higher than 0.999.The average recoveries of high,medium and low three spiked concentration levels were between 83% and 111%,with relative standard deviations（RSDs） of 2.3%-9.2%.The limits of detection（LOD） were in the range of 0.008 7-0.17 mg/kg for the four components in juice matrix,and their limits of quantitation(LOQ) were 0.029-0.58 mg/kg.The results demonstrated that the proposed method for laccaic acids determination in juice could meet the requirements for the natural color analysis in food safety.关键词：UPLC/TUV;UPLC-MS/MS;natural pigment;laccaic acids;juice
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- 1411
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- 4
发布时间： - 摘要：Using the method of chemical co-precipitation，the super paramagnetic nanoparticles with the key component of Fe3O4 were synthesized.The magnetic beads reacted with the silane coupling agent 3-aminopropyl triethoxysilane and connected with amino groups.After activated by the agent glutaraldehyde，the magnetic beads took along the aldehyde group and coupled with aflatoxin B1 polyclonal antibody to form the immune magnetic beads.A method was established to detect the aflatoxin B1 in vegetable oil by using the organic solvent for preliminary extraction，the aflatoxin B1 immune magnetic beads system to purification and HPLC to quantification.The method showed a good linearity in the range of 5-50 μg/L with correlation coefficient of 0.999 4 and detection limit of 0.5 μg/L.The average recovery was up to 96% and the RSD was 12.5%.With the advantages of simplicity，sensitivity and high accuracy，the method could be applied in the determination of aflatoxin B1 in vegetable oil.关键词：immune magnetic beads;vegetable oil;aflatoxin B1
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- 917
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- 12
发布时间： - 摘要：A method was developed for the determination of 11 triazole pesticides residues in fruits and vegetables using gas chromatography-mass spectrometry（GC-MS）.The samples were homogeneous extracted with acetonitrile and then cleaned up by a solid phase extraction（Sep-Pak CarbonNH2） cartridge,eluted with acetonitrile-toluene（3∶1）.The elution solvent was concentrated,solvent exchanged to constant volume,then determined by GC-MSD/SIM with the internal standard method.The calibration curves of 11 triazole pesticides were linear in the range of 0.05-5 ng with correlation coefficients of 0.996-1.000.The spiked recoveries of 11 triazole pesticides from five matrices（e.g.cabbage,tomato,apple,orange,spinach） at three spiked levels of 0.01,0.05，0.10 mg/kg were in the range of 80%-97% with relative standard deviations（RSDs,n=10） of 2.5%-8.4%.The limits of detection were 0.01 mg/kg for 11 triazole pesticides.The method is simple,sensitive,accurate and reliable.关键词：gas chromatography-mass spectrometry（GC-MS）;vegetables;fruits;triazole pesticides
- 2110
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- 1053
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- 11
发布时间： - 摘要：A dispersive solid phase extraction coupled with high performance liquid chromatographic（HPLC） method was established for the determination of robenidine in fishery products.The sample was extracted with acidified ethyl acetate as extraction solvent and C18 as the sorbent，then purified by alumina-N.After evaporated to dryness，the residue was redissolved in acetonitrile water solution and defatted with n-hexane.The external standard method was used to quantify robenidine.The optimization chromatographic conditions were as follows：separation column：Agilent ODS-C18 chromatographic column（250 mm×4.6 mm，5 μm），mobile phase：pH 6.8 acetonitrile-ammonium dihydrogen phosphate buffer（65∶35，by volume），flow rate：1.0 mL/min，column temperature：40 ℃，sample volume：20 μL，detection wavelength：353 nm.Under the optimal conditions，the calibration curve showed a good linearity in the range of 0.01-1.00 mg/L with a correlation coefficient of 0.999 9.Four common representative samples（tilapia，eel，shrimp and turtle） were chosen for the validation of the method by recovery and precision.The obtained recoveries were 76%-106% and the relative standard deviations were 0.81%-8.2%.The limit of detection was 10 μg/kg，and the limit of quantitation was 30 μg/kg.Results of three inter-laboratory validation tests showed that the recoveries of robenidine in fish，shrimp and turtle samples at three spiked concentration levels were greater than 70% with relative standard deviations not more than 11%.With the advantages of simple operation，good sensitivity，accuracy and reproducibility，the proposed method was successfully used in the determination of robenidine in real samples,which can be recommended as the related test method for application.关键词：fishery products;robenidine;dispersive solid phase extraction;high performance liquid chromatography（HPLC）
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- 1133
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- 7
发布时间： - 摘要：A rapid and environmental-friendly analytic method was established for the determination of deoxynivalenol(DON)in grain samples.The samples were extracted with water, cleaned up with immunoaffinity column（IAC）.The separation of targeted compound was performed on a Waters Acquity UPLC BEH C18（2.1 mm×50 mm, 1.7 μm） using methanol-water（10∶90） as mobile phase with a flow rate of 0.1 mL/min at 25 ℃.The injection volume was 1 μL for UV detection at 220 nm and the retention volume was less than 0.5 mL.The whole process from sample pretreatment to analysis took less than 45 min.The linear range of deoxynivalenol was in the range of 0.5 -10.0 mg/L with a correlation coefficient of 0.999 96.The limit of detection（LOD） was 0.15 ng and the limit of quantitation（LOQ） was 0.5 ng.The average recoveries were between 84% and 98% with RSDs of 2.9%- 5.9%.The method was suitable for the determination of DON in the raw grain, with advantages of simplicity, rapidness, sensitivity, good reproducibility and environment friendly.关键词：grain;deoxynivalenol;UPLC;immunoaffinity column(IAC)
- 2045
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- 1120
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- 8
发布时间： - 摘要：A comprehensive analytical method based on high performance liquid chromatography tandem mass spectrometry（HPLC-MS/MS） was developed for the determination of aldicarb,aldicarb sulfone and aldicarb sulfoxide residues in ginger,tomato,spinach,rice,peanut,soybeans,almonds,apples,citrus,tea,liver and chicken samples.Various samples were extracted with acetonitrile.The extract was purified with soild phase extraction（SPE） column,and then separated on an Agilent（3.5 μm,100 mm×2.1 mm） column.The detection was performed by MS/MS under positive electrospray ionization and multiple reaction monitoring（MRM） mode,with the external standard method.The result indicated that the calibration curves showed good linearities for aldicarb,aldicarb sulfone and ablicarb sulfoxide in the range of 0.01-0.2 mg/L.The limit of detection for the method was 0.002 mg/kg and the limit of quantitation was 0.01 mg/kg.The mean recoveries at three spiked concentration levels（low,middle,high） were between 68% and 89%.The method is reliable,sensitive and reproducible,and could be rapidly applied in the determination of aldicarb,aldicarb sulfone and aldicarb sulfoxide residues in different foods.
- 2511
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- 1192
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- 6
发布时间： - 摘要：A QuEChERS with high performance liquid chromatographic（HPLC） method was developed for the determination of 17 phthalate esters（PAEs），e.g.DMEP，DMP，DEEP，DEP，DPhP，BBP，DIBP，DBP，DBEP，DPP，DCHP，BMPP，DHXP，DEHP，DNOP，DINP and DNP，in food samples．The targeted compounds were extracted with acetonitrile，and purified by PSA-based QuEChERS（50 mg PSA and 150 mg MgSO4）.The extract were separated on a C18 column with mobile phase composed of water and acetonitrile by gradient elution at a flow rate of 1.0 mL/min.The UV detection wavelength was set at 224 nm.Under the optimal conditions，the calibration curves of phthalate esters were linear in the ranges of 0.5-10 mg/L for DINP and 0.05-10 mg/L for the others with correlation coefficients（r2） more than 0.99.The average recoveries of 17 analytes from 5 kinds of food matrixes were in the range of 70%-120% with RSDs（n=6）less than 15%．The detection limits（LODs，S/N=3） of phthalate esters were 0.001-0.02 mg/L and the quantitation limits（LOQs，S/N=10） were 0.05-0.5 mg/kg．The proposed procedure was applied in the analysis of 432 real samples from Xiamen，Fujian province（China），in which 18 positive samples were found.The proposed method was simple and accurate，and could be applicable for the routine analysis of monitoring PAEs residues in foodstuffs.关键词：phthalate esters（PAEs）;QuEChERS;high performance liquid chromatography（HPLC）;food
- 2997
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- 1189
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- 13
发布时间： - 摘要：A rapid analytical method was developed for the determination of 14 heterocyclic aromatic amines（HAAs） in meat products by liquid chromatography-ion trap-time of flight tandem mass spectrometry（LCMS-IT-TOF）.The samples were extracted with acetonitrile.The extract was cleaned up with Phenomenex strata-X-C,eluted with methanol-ammonia（9∶1）,then evaporated with a stream of nitrogen to near dryness and redissoved with acetonitrile-water（1∶9）.The separation of HAAs was performed on a Phenomenex Kinetex 2.6μ C18 100A （2.1 mm i.d.×100 mm,2.6 μm）,using 30 mmol/L ammonium formate-acetonitrile as mobile phase by gradient elution.The analytes were detected under positive ion electrospray ionization mode.Results showed that the linear ranges of 14 HAAs were 5-250 μg/L with limits of detection（S/N=3） of 0.59-3.27 μg/kg．The mean recoveries of all the compounds at three spiked levels of 10,50,250 μg/kg were in the range of 69%-107%,67%-106% and 76%-113%,respectively,with the corresponding RSDs（n=6） of 1.5%-15.6%,1.3%-11.8% and 1.8%-9.7%,respectively.The established method showed a wide liner range and a high sensitivity,and could meet the requirements for the simultanous analysis of the HAAs in meat products.关键词：liquid chromatography-ion trap-time of flight tandem mass spectrometry（LCMS-IT-TOF）;meat products;heterocyclic aromatic amines（HAAs）
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- 1044
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发布时间： - 摘要：A method was developed for the determination of zoalene and its metabolite(3-amino-5-nitro-o-toluamide,3-ANOT) in chicken muscle by dispersive solid phase extraction and liquid chromatography tandem mass spectrometry(LC-MS/MS).The samples were extracted with acetonitrile and purified by dispersive solid phase extraction method.After diluted with 0.1% formic acid,the extract was filtered through 0.22 μm filter and 10 μL of the filtrate was injected into LC for analysis.The target compounds were separated on an Acquity BEH C18 column with acetonitrile-0.1%formic acid as mobile phase with gradient elution,and detected by MS under multiple reaction monitoring(MRM) with positive and negative ionization switching mode.The analytes were quantified by the external standard .Good linearities were obtained for zoalene and 3-ANOT at the concentration of 1-500 μg?L-1,with correlation coefficients of 0.999 5 and 0.999 4,respectively.The recoveries of zoalene and 3-ANOT in chicken muscle at fortified levels of 50-4 500 μg?kg-1 were between 81% and 94%.The intra-assay RSDs were in the range of 2.1%-5.3% and the inter-assay RSDs were 4.3%-6.2%.The limits of detection of zoalene and 3-ANOT were 10 and 14 μg?kg-1,respectively,and their limits of quantitation were both 50 μg?kg-1.The results indicated that the method could meet the requirement for simultaneous determination of zoalene and 3-ANOT in chicken muscle.关键词：chicken muscle;dispersive solid phase extraction;liquid chromatography-tandem mass spectrometry;zoalene;metabolite;residue
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- 1035
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- 1
发布时间： - 摘要：A high performance liquid chromatographic(HPLC) method was developed for the determination of morphine，codeine,thebaine,papaverine and narcotine in three types of food including spices class,halogen soups and cooked food categories.The food samples were ultrasonically extracted with ethanol,and then separated on a C18 column(250 mm × 4.6 mm,0.5 μm) with methanol-0.01 mol?L-1 phosphate buffer as mobile phase at a flow rate of 1.0 mL?min-1.The UV wavelength was set at 250 nm.The result indicated that the standard curves of five alkaloids were linear in the range of 10-600 mg?L-1 with correlation coefficients not less than 0.999 6.The detection limits of five alkaloids were between 0.1 mg?kg-1and 0.6 mg?kg-1.The average recoveries of 5 alkaloids from three matrices at high and low spiked levels ranged from 88% to 108%,with relative standard deviations(RSD,n=6) ranged from 0.77%to 10.7%.The method was simple,sensitive,accurate and repeatable,and could be used for the determination of five alkaloids in food sample.关键词：poppy;alkaloid;HPLC;food
- 2231
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- 1126
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- 10
发布时间： - 摘要：A high performance liquid chromatographic（HPLC） method was established for the rapid determination of formaldehyde in potato starch noodles.The type of derivative reagent，derivative reaction conditions and derivative stability were investigated.The separation of formaldehyde was carried out on an Agilent Zorbax Eclipse XDB-C18column（4.6 mm×250 mm，5 μm），using a mobile phase composed of acetonitrile- water（30∶70） at a flow rate of 0.8 mL/min.The variable wavelength detector（VWD） was set at 412 nm.Under the optimal conditions，the calibration curve was linear in the concentration range of 0.00-0.80 mg/L with a correlation coefficient of 0.999 8.The spiked recoveries of formaldehyde in potato starch noodles were in the range of 92%-94%with relative standard deviations（RSD） of 0.75%-1.5%. The detection limit was 0.043 μg/g.The method is simple，rapid and accurate，and could be used in the determination of formaldehyde content in potato starch noodles.关键词：Nash derivatization;potato starch noodle;formaldehyde;rapid determination;HPLC
- 2578
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- 1327
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- 3
发布时间： - 摘要：A new method was developed for the determination of borax（boric acid） in puffing foods using non-suppressed ion chromatography.The samples were extracted with methanesulfonic acid by ultra-sound.The solution was made passed through OnGuard Ⅱ RP，Ag column，Na column and filter membrane after centrifugation and filtration.The separation of boric acid was performed on an anion exchange column of Dionex Ionpac AG16（50 mm×4 mm） +AS16（250 mm×4 mm） with 5 mmol/L sodium hydroxide by isocratic elution at a column temperature of 30 ℃.The optimum chromatography conditions were investigated.Under the optimal conditions，the calibration curve for boric acid showed a good linearity in the range of 0.3-3.0 mg/g with correlation coefficient of 0.999 5.The spiked recoveries for boric acid were in the range of 78%-105% with RSDs of 1.5%-4.6%.The detection limit was 0.06 mg/g.This method was applicable for the determination of borax（boric acid） in puffing foods.关键词：Non-suppressed ion chromatography;puffing foods;borax（boric acid）
- 3073
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- 1291
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- 0
发布时间： - 摘要：In this study，the binding mode of a synthesized copper（Ⅱ） complex of 2-hydroxy acetophenone（HAP），［Cu（HAP）2］（1），to calf thymus DNA（ct-DNA） as biomolecular target was discussed by UV-Vis absorption，fluorescence emission and circular dichroism spectra，as well as DNA viscosity titration experiment.Results indicated that complex 1 binds to ct-DNA mainly via intercalation and exterior electrostatic interaction，in which intercalation can be ascribed to aromatic ring of HAP and the rigid planar structure of whole complex 1，while electrostatic interaction to DNA polyanionic backbone should be attributed to the cationic copper（Ⅱ） center of complex 1.The research results provided scientific evidence for the further exploration of the pharmaceutical activities of serial metal complexes of HAP.关键词：2-hydroxy acetophenone;copper（Ⅱ） complex;ct-DNA;spectral analysis;intercalation
- 3308
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- 1174
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- 2
发布时间： - 摘要：Surface sediment samples were collected from eleven stations of Jiaozhou Bay，the Yellow Sea in July 2009，and concentrations of eight heavy metals were measured.Effects of the construction of Jiaozhou Bay Bridge on metal distribution and contamination were evaluated.The concentrations of heavy metals were generally low in this survey，in which the average concentrations of Hg，Cu，Pb，Zn，Cd，Ni，Co，Mn were 0.031，19.05，12.7，51.14，0.055，17.31，8.24，775 mg/kg，respectively.The pollution levels and potential ecological risks of heavy metals were evaluated by Geoaccumulation index and Hankanson’s method.The results displayed that almost all the metals were at low pollution levels except for Hg.The heavy metal distribution among stations in this survey suggested the disturbance of sediments by the construction of oversea bridge，which might increase the risk of cross-contamination of pollutants in sediments.关键词：heavy metals;marine environment;Jiaozhou Bay;the Yellow Sea;potential ecological risk
- 3021
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- 1123
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- 22
发布时间： - 摘要：A direct derivatization and high-performance liquid chromatographic method was developed for the trace analysis of 8 carbonyl compounds,e.g.formaldehyde,acetaldehyde,acetone,acrolein,propaldehyde,crotonaldehyde and 2-butanone and butaldehyde in water-based adhesive.The method adopted 2,4-dinitrophenylhydrazine（DNPH） to directly react with the adhesive sample solution,and the influence factors were investigated and optimized.The best derivatization condition was using the adhesive to react directly with DNPH at 40 ℃ for 20 min.The optimized chromatograpic conditions were as follows:DIONEX Acclaim Explosives E2 reversed-phase column as separation column,water and acetonitrile as mobile phase by double gradient elution.The flow rate was set at 1.2 mL/min,and the column temperature was set at 35 ℃.Under the optimal conditions,the linear ranges of 8 carbonyl compounds were all in 0.001 1-55.32 mg/L，with correlation coefficients higher than 0.999.The limits of detection for 8 carbonyl compounds were 0.066 3-1.691 1 mg/kg,and the limits of quantitation were 0.221-5.637 mg/kg.The relative standard deviations were between 4.3% and 9.3%,and the recoveries were 62%-100%.The established method was sensitive,simple and accurate,and was practical for the determination of 8 carbonyl compounds in wate-based adhesive.关键词：direct derivatization;solvent extraction;high-performance liquid chromatography;carbonyl compounds;water based adhesive
- 2275
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- 1001
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- 1
发布时间： - 摘要：A liquid chromatography-tandem mass spectrometric（LC-MS/MS） method was developed for the simultaneous determination of indole-3-butyric acid（IBA），indole-3-acetic acid （IAA） and its 7 amino acid conjugates including IAA-Asp,IAA-Ala,IAA-Val,IAA-Trp,IAA-Leu,IAA-Ile and IAA-Phe in rice．The sample was extracted with 80% methanol for 12 h at 4 ℃.The extract was cleaned up on an Oasis MAX cartridge（60 mg×3 mL）,and eluted with methanol contained 05% formic acid.9 analytes were separated on a C18 column （1.8 μm,100 mm×2.1 mm i.d.） using 5 mmol/L ammonium formate（A） -acetonitrile（B） as mobile phase by gradient elution.The analytes were detected by positive-ion electrospray ionization-mass spectrometry under multiple reaction monitoring（MRM） mode.The recoveries of 9 analytes from the matrixes of root,sheath,leaf and seed in rice tissue ranged from 75% to 106% with relative standard deviations（RSDs） of 3.6%-15.2%.The detection limits(S/N=3) ranged from 0.01 μg/kg to 25 μg/kg.The method was sensitive and reliable,and could meet the requirements for quantification of auxins and their amino acid conjugates in rice at the physiological level.关键词：liquid chromatography-tandem mass spectrometry（LC-MS/MS）;auxin;amino acid conjugates;rice
- 2115
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- 1002
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- 2
发布时间： - 摘要：To quantitative analyzing four polyphenolic compounds of gallic acid,punicalagin A,punicalalgin B and ellagic acid in pomegranate peel water extracts，a high performance liquid chromatographic（HPLC） method was established.The samples were prepared and filtered prior to the HPLC analysis.Quantification analysis of these analytes were achieved under the optimized HPLC conditions using the external standard method.The results showed that the calibration curves for gallic acid,punicalagin A，punicalagin B and ellagic acid were linear in the concentration ranges of 7.48-149.50，15.36-153.55，27.65-276.45，7.13-114.00 mg/L，respectively，with their correlation coefficients（r2） greater than 0.99.The limits of detection（LOD） were 0.12，1.92，3.46,0.22 mg/L，and the limits of quantitation（LOQ） were 0.48，7.68，13.83,0.89 mg/L，respectively.The spiked recoveries ranged from 83% to 112% with relative standard deviations（RSDs） less than 10%.The developed method was simple，sensitive，reliable and reproducible，and could be applied in the rapid determination of gallic acid，punicalagin A，punicalagin B and ellagic acid in pomegranate peel water extracts in 17 min.关键词：punicalagins A & B;gallic acid;ellagic acid;pomegranate peel water extracts;high performance liquid chromatography
- 2492
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- 1140
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- 7
发布时间： - 摘要：A method of polyacrylic acid-complexation and ultrafiltration for matrix modification and inductively coupled plasma mass spectrometry（ICP-MS）was developed for the determination of 24 trace level of rare earth elements（REEs） and metal elements in coastal and estuarine seawater.REEs ions，Cu2+,Pb2+,Cd2+,Co2+,Ni2+ could reacted with polyacrylic acid（PAA） to form stable complexes when the pH value was above 7.5，which could be separated and enriched absolutely after trapped and eluted from the ultrafilter.Full quantitative data collection mode and internal standard calibration curve were used for the ICP-MS determination.Under the optimized conditions，the relative standard deviations（RSDs） were in the range of 1.7%-7.3%，and the spiked recoveries were between 73% and 96%.The limits of quantitation（LOQs，10σ） ranged from 0.23 ng/L to 13.9 ng/L.The method blank ranged from 0.09 ng/L to 8.38 ng/L.The developed method could be applied in the simultaneous determination of REEs and metal elements in coastal and estuarine seawater.关键词：poly（acrylic acid）-metal complex;ultrafiltration;inductively coupled plasma mass spectrometry;seawater;rare earth and metal elements
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- 996
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- 6
发布时间： - 摘要：Based on the fact that venlafaxine had remarkable enhancing effect on Ag（Ⅲ） complex-luminol chemiluminescence（CL） system，a novel method for the determination of venlafaxine was established by CL method with flow-injection analysis.Under the optimum conditions，the calibration curve was linear in the range of 0.1-2.0 mg?L-1 with detection limit（S/N=3） of 0.05 mg?L-1.The relative standard deviation（n=11） for 0.1 mg?L-1 venlafaxine was 0.87%，and the recovery ranged from 96% to 105%.This method was simple，sensitive and accurate，and was successfully applied in the determination of venlafaxine in capsules.关键词：venlafaxine;luminol;Ag（Ⅲ） complex;flow injection;chemiluminescence（CL）
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- 860
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- 4
发布时间： - 摘要：Mesoporous zirconia samples with high thermal stability were synthesized by hydrothermal homogeneous precipitation method using an anionic surfactant as template.In this method,sodium dodecyl benzene sulfonate（SDBS) not only functioned as a directing agent for mesoporous structure but also functioned as a mesoporous structure stabilizer with the sulfonic groups converted to SO2-4after calcination.The samples were characterized by TEM,nitrogen adsorption-desorption isotherms,XRD and FT-IR.The N2 adsorption analysis showed that the zirconia still has a surface area of 156 m2/g after calcination at 500 ℃.The TEM analysis displayed that it has a worm-like mesoporous structure with a pore size about 2.9 nm.The XRD analysis displayed that the prepared zirconia continuous to present a pure tetragonal phase,with good thermal stability even calcinated at 600 ℃.关键词：anionic surfactant;mesoporous zirconia;thermal stability
- 2016
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- 1072
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- 1
发布时间： - 摘要：An analytical method was established for the determination of distearyl dimethyl ammonium chloride（DSDMAC) in dyeing and finishing textile agents by ultrasound assisted extraction combined with liquid chromatography-tandem mass spectrometry（LC-MS/MS).The sample was extracted with methanol by ultrasound-assisted extraction.The extract was filtered and then detected by LC-MS/MS with electro spray ionization source.The confirmation ion pairs were m/z 550.5/298.3，522.5/298.3，522.5/270.3，494.5/270.3,and the quantification ion pairs were m/z 550.5/298.3，522.5/298.3，494.5/270.3.The calibration curve was linear for DSDMAC in the range of 0.02-1.0 mg/L with correlation coefficient of 0.998 5.The limit of quantitation was 20 mg/kg.The recoveries of DSDMAC at the spiked range of 100-500 mg/kg were between 86% and 96%，with relative standard deviations（RSDs)of 3.2%-5.4%.The experimental results indicated that the method was rapid,sensitive and accurate,and could meet the correlative requirements for determination of DSDMAC in dyeing and finishing textile agents.关键词：ultrasound-assisted extraction;liquid chromatography-tandem mass spectrometry（LC-MS/MS);dyeing and finishing textile agents;distearyl dimethyl ammonium chloride（DSDMAC)
- 2451
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- 994
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- 2
发布时间： - 摘要：A flame atomic absorption spectrometric method coupled with ionic liquids based ultrasonic assisted extraction was developed for the determination of the migration of trace cadmium in oil pastel.The main factors affecting the extraction efficiency,such as pH value,amount of metal chelating,ionic liquid and nitric acid,ultrasonic extraction time,metal ions interference and chain length of ionic liquid were studied.The optimal conditions were as follows：pH value：9.0,metal chelating amount：2.00 mL,amount of ionic liquid：2.00 mL,amount of nitric acid：4.00 mL 1.00 mol?L-1,ultrasonic extraction time：5 min.Under the optimized conditions,the extraction efficiency of Cd2+ reached up to 99%,and the enrichment times was 25.The other metal ions made no effects on the extraction efficiency of Cd2+ except for Cu2+ and Pb2+.The recoveries for the method varied from 96% to 103% with relative standard deviation（n=11） of 1.7%，and the detection limit was 0.016 mg?L-1.关键词：ionic liquid;heavy metal Cd2+;ultrasonic-assisted extraction;enrichment;oil pastel
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