最新刊期
卷 31 ， 期 10 ， 2012
- 摘要：A based on automated online gel permeation chromatography coupled with gas chromatography-mass spectrometry(GPC-GC/MS) method was developed for the rapid determination of 29 pesticide residues in cereals and oil crops.Pesticides were extracted from cereals and oil crops samples with acetonitrile and decontaminated via primary secondary amine(PSA) sorbents,then determined by GPC/GC-MS.The identification and detection of target compounds were achieved in electron impact(EI) mode under selected ion monitoring(SIM) mode.The calibration curves of 29 pesticide residues were linear in the range of 0.25-600 μg?L-1 with good correlation coefficients more than 0.99.The recoveries for all compounds in feeds at three fortified levels of 1MRL,2MRL and 4MRL were in the range of 65%-148%.The limits of quantitation(LOQs,S/N=10) for 11 pesticides(e.g.dieldrin,parathion-ethyl and methamidophos,etc.) were in the range of 2.0-6.0 μg?kg-1 and those of the other 18 pesticides(such as dichlorvos,dimethoate and HCH,etc.) were less than 1.0 μg?kg-1.The method was simple,rapid and reliable,and could meet the require-ment for the simultaneous determination and analysis of 29 pesticide residues in cereals and oil crops.关键词：online gel permeation chromatography coupled with gas chromatography-mass spectrometry(GPC/GC-MS);pesticide residues;cereals;oil crops
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发布时间： - 摘要：A graphene/Fe3O4 magnetic nanocomposite(G/Fe3O4) was synthesized and used as an adsorbent for the dispersive solid phase extraction of diethylstilbestrol(DES) in environmental water.The chemical structure of graphene/Fe3O4 magnetic nanocomposite was investigated by FT-IR and X-ray diffraction spectra.The effects of pH value，adsorption time and salt on the adsorption of DES were examined.Results showed that the best pH value is 7.0，the balance adsorption time is 20 min，and the obtained highest adsorption efficiency is 88.2%.Absolute ethyl alcohol was effective in eluting DES on the G/Fe3O4 and could realize the recycling of adsorbent.The adsorption behavior followed Langmuir adsorption isotherm with a maximum adsorption capacity of 79.6 mg/g and a Langmuir adsorption equilibrium constant of 5.39 mL/μg.关键词：graphene/Fe3O4 magnetic nanocomposite;synthesis;diethylstilbestrol;adsorption;elution
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发布时间： - 摘要：A method based on ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS） was developed for the simultaneous determination of three industrial acid dyes，namely acid orange Ⅱ，acid orange Ⅲ and acid orange AGT，in meat products.The samples were extracted with acetonitrile（containing 5% ammonia），cleaned up and enriched with WAX solid phase extraction（SPE) cartridge，and then analyzed by UPLC-MS/MS under the multiple reaction monitoring（MRM） mode.All the analytes were successfully detected in negative ion mode by adding an ion-pair reagent of dihexylammonium acetate（DHAA） to the mobile phase in 6 min.The calibration curves were linear between 5.0 μg/L and 300 μg/L，and the correlation coefficients（r） were more than 0.999.The limits of detection（LOD，S/N=3） and the limits of quantitation（LOQ，S/N=10） were in the range of 20.0-50.0 μg/kg and 70.0-170.0 μg/kg，respectively.The spiked recoveries were in the range of 83%-89%，and relative standard deviations （RSD，n=3） were no more than 7.5%.The method was simple，effective and sensitive，and was suitable in the determination and confirmation of three industrial acid orange dyes in the meat product samples.关键词：ultra performance liquid chromatography tandem mass spectrometry;multi reaction monitoring;acid orange Ⅱ;acid orange Ⅲ;acid orange AGT;ion-pair;meat product;food safety
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发布时间： - 摘要：A novel hydrogen peroxide biosensor was constructed based on horseradish peroxidase(HRP) immobilized onto glass carbon electrode(GCE),which was modified with the nanocomposite of gelatin and multi-walled carbon nanotubes(MWCNTs).The electrochemistry and electrocatalysis of the modified biosensor were investigated.A pair of well-defined and nearly symmetrical redox peaks with a formal potential of -0.356 V(vs.SCE) in PBS were observed,which attribute to the direct electron transfer between the entrapped HRP and the electrode.The redox peak current was proportional to scan rate in the range of 20-180 mV/s,indicating that the process was affected by electronic transfer electrode rate control surface of mass transfer process.The electrochemical characteristics of the modified electrode were investigated by cyclic voltammetry.The effects of applied potential,solution pH and interferences on the biosensor were discussed.The results demonstrated that HRP could display an excellent electrocatalytic response to the reduction of hydrogen peroxide.Furthermore,the biosensor exhibited a more sensitive catalytic activity on H2O2 in a hydrophilic ionic liquid,1-butyl-3-methylimidazolium tetrafluoroborate(［BMIM］BF4),than that in PBS buffer.A wide linear response to H2O2 in the range of 2.0×10-7-0.13 mol/L was obtained with a detection limit(S/N=3) of 2.3×10-8 mol/L.The modified electrode exhibited the advantages of good stability,wide linear range and lower detection limit as well as a certain anti-interference ability.关键词：carbon nanotubes;gelatin;horseradish peroxidase;ionic liquid;hydrogen peroxide
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发布时间： - 摘要：A high performance ion exchange chromatographic method coupled with pulsed amperometric detection was established for the analysis of amylopectin chain length distribution.The amylopectin was hydrolysised into unit chain under the function of isoamylase which can broke the α-1，6 chain of glucan.The determination method was optimized by comparing different chromatographic columns and elution conditions.Water,100 mmol/L NaOH and 1 mol/L NaAc+100 mmol/L NaOH aqueous solution were used as mobile phase,and the analysis of degree of polymerization (DP) more than 80 could be achieved by using CarboPac PA20 anion exchange column.Maize,cassava,potato and rice starch were selected as the example for the determination of chain length distribution,which could be used to judge their molecular configurations.This method was proved to be simple,extensive and reproducible,and the RSD was less than 5% when the DP was under 65.The method could provide the basis for further research of physical and chemical properties of starch and breed improvement.关键词：Chain-length distribution;amylopectin;ion chromatography;amperometric detection
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发布时间： - 摘要：Cyromazine molecularly imprinted polymers（MIPs） were synthesized by UV photo-initiation and bulk polymerization method at low temperature,using cyromazine as template molecule，methacrylic acid（MAA） as functional monomer, ethylene dimethacrylate（EDMA） as cross linker,toluene and isooctane as binary porogen.Comparative determination and characterization of the prepared MIP and NIP were carried out by equilibrium adsorption experiment,scanning electron microscope（SEM）,infrared absorption（IR） and mercury analyzer（MA）.The results showed that the MIPs possessed the specific adsorptivity toward the template molecule.Scatchard plot′s analysis revealed that the apparent maximum binding capacity and the dissociation contents were as the follows：Qmax1=119 μmol/g，Kd1=131 μmol/L；Qmax2=2.46 μmol/g，Kd2=4.84 μmol/L.It was demonstrated that the proposed MI-SPE/HPLC method could be successfully applied in the determination of cyromazine in cucumber sample.A linear calibration curve was obtained in the concentration range of 0.1-10 mg/L（r=0.999 1） with a detection limit of 0.05 mg/L.The established method was simple and rapid,and had a better effect than commercial SPE column.关键词：cyromazine;photo polymerization;molecularly imprinted polymer;solid phase extraction;HPLC
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发布时间： - 摘要：Butadiene and isoprene copolymerization were carried out at 50 ℃ in hexane for 8 h using Nd(P507)3/AlH(i.Bu)2/AlEt2Cl catalyst.The catalyst was aging at 60 ℃ for 2 h before initiation.FTIR method was used to determine the microstructure of butadiene isoprene copolymer.The result showed the copolymer was of high cis-1,4 content in both polybutadiene unit(cis-1,4=93.1%-97.7%) and polyisoprene unit(cis-1,4=97.0%-97.5%).DSC determination indicated that the copolymer was of excellent low temperature resistance.The butadiene-isoprene copolymers showed only one glass transition temperature(Tg) from -107.2 ℃ to – 64.4 ℃,which increased with the increasement of the isoprene ratio.The correlation deviated from Fox equation,and could be modified as Tg＝1.03TgIWI+TgBWB.The reactivity rate of the copolymer was calculated by Kelen-Tudos method.It turned out that the reactivity rates of butadiene(r1) and isoprene(r2) were 1.21 and 0.73，respectively.The product of r1 and r2 was close to 1,which indicated the product is a random structure.The 13C NMR spectrum was used to determine the sequence distribution of the copolymer.The peak position in the aliphatic carbon part showed no difference while the composition changed in the copolymer.The compositions of 4 dyads of random butadiene-isoprene copolymers and the number average sequence length of polybutadiene and polyisoprene were calculated based on the peak area of 13C NMR spec-trum.The data were analyzed and examined in use of the statistical formula under Bernoullian model and Markov model.It turns out that all the data are more identical with Markov model than Bernoullian model.Moreover,the copolymer chains with higher Bd content contain longer polybutadiene segments,while the copolymer chains with higher Ip content contain longer polyisoprene segments.关键词：FTIR;13C NMR;neodymium phosphate catalyst;butadiene isoprene copolymer;reactivity ratio;sequence distribution
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发布时间： - 摘要：A new amino acid structure descriptor,namely SVHEHS,was derived from the principal component analysis of 457 physicochemical properties of natural amino acids.The descriptor was used to characterize the structures of angiotensin converting enzyme(ACE） inhibitory dipeptides,tripeptides and tetrapeptides,and then the mathematic models between the structures and the activities of three panels of peptides were established by artificial neural networks.The correlative coefficient(r2）,the cross-validation correlative coefficient(Q2LOO）,root mean square error(RMSE）,external validation correlative coefficient(Q2ext） for the dipeptides model were 0.946,0.951,0.249 and 0.852,respectively,for tripeptides model were 0.973,0.945,0.135 and 0.813,respectively,and for tetrapeptides model were 0.915,0.879,0.250 and 0.814,respectively.The result indicated that the models based on SVHEHS descriptor combined with neural networks had good fitting and predictive abilities.Moreover,the key structure factors relevant with peptide activities were studied by the mean impact value method.The results can be helpful for the molecular designs of new ACE inhibitory peptides.关键词：angiotensin converting enzyme;peptides;neural networks;quantitative structure-activity relationship
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- 1021
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发布时间： - 摘要：A liquid chromatography-tandem mass spectrometric method was developed for the simultaneous determination of 5 avermectin residues（e.g.abamectin,ivermectine,eprinomectin,emamectin benzoate B1a and emamectin benzoate B1b） in fruits and vegetables.After extracted with acetonitrile,avermectin residues were cleaned up by PSA and C18 dispersive solid phase extraction.Influences of mobile phases,procedure of solvent gradient and temperature of the desolvation gas were investigated.Experimental results revealed that the most signal intense precursor ions（［M+ NH4］+） were observed when desolvation gas temperature of 250 ℃ was used.The method was evaluated in terms of the limits of detection and quantitation.The linearity of the analytical response within the studied range of 3 orders of magnitude was excellent,with correlation coefficients higher than 0.999.The mean recoveries of all analytes in 5 spiked fruits and vegetables matrix were in the range of 74%-110%,with relative standard deviations of 0.4%-12.1%.The limits of detection for abamectin,ivermectine,eprinomectin,emamectin benzoate B1a and emamectin benzoate B1b were 0.6,0.6,0.3,0.06,0.6 μg/kg,respectively.The method was efficient,reliable and sensitive,and could meet the requirements for the determination of 5 avermectin residues in fruits and vegetables.关键词：liquid chromatography-tandem mass spectrometry（LC-MS/MS）;avermectin residues;fruits;vegetables
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发布时间： - 摘要：The different types of food simulated migration of ten phthalic acid esters in food paper packaging materials were replaced by distilled water，3% acetic acid，10% ethanol and 95% ethanol.The ten phthalic acid esters in four food simulants were enriched and purified by C18 solid phase extraction column，and separated on an Eclipse XDB-C18（4.6 mm×150 mm，5 μm，Agilent）column using acetonitrile and water as mobile phases.The analysis of ten phthalic acid esters was performed by high performance liquid chromatography with a diode array detector.Under the optimal conditions，all of the ten phthalate acid esters had the same maximum absorbance at 224 nm，The calibration curves were linear in the certain concentration range with correlation coefficients（r2） higher than 0.999 9.The recoveries at spiked levels of 0.05，0.1,0.2 mg?L-1 ranged from 71% to 107% with RSDs of 0.86%-8.0%.The limits of detection were lower than 0.1 mg/kg.The method was simple，rapid and reliable，and could meet the requirements for relevant limit regulations.关键词：high performance liquid chromatography;food simulants;paper food contact materials;phthalic acid esters;solid phase extraction
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发布时间： - 摘要：The essential oil components in herbal pair(HP）Pericarpium Citri Reticulatae-Pericarpium Citri Reticulatae Viride（PCR-PCRV） and its single herbs were respectively extracted by steam distillation,then qualitatively and quantitatively analyzed by gas chromatography-mass spectrometry(GC-MS） and a chemometric resolution method,namely heuristic evolving latent projections(HELP）.In addition,temperature programmed retention indices(PTRIs） were employed to improve the precise degree of qualitative analysis.To sum up,27,27 and 23 volatile chemical components in essential oils of PCR,PCRV and HP PCR-PCRV were separated and identified,accounting for 93.64%,96.45% and 85.28% of total contents of the three tested samples,respectively.There are a total of 19 common compounds.The main volatile constituents in PCR,PCRV and HP PCR-PCRV are D-limonene,(γ)-terpinene,linalool and α-farnesene.关键词：herbal pair(HP）;Pericarpium Citri Reticulatae-Pericarpium Citri Reticulatae Viride(PCR-PCRV）;GC-MS;HELP;volatile oil;PTRI
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发布时间： - 摘要：A thin layer chromatography(TLC）-fluorescence scanning method was established for the determination of camptothecine(CPT） and 10-hydroxycamptothecine(10-HCPT） in Chinese herbal medicine Xishuguo(Common camptotheca fruit,CCF）.Methanol was used as solvent to extract CPT and 10-HCPT in CCF sample.The separation was carried out on silica gel H plate using chloroform-acetone(7∶3） as developing agent.The determination was accomplished by fluorescence linear scanning with excitation wavelength of 350 nm.In the quality range of 0.010 5-0.063 0 μg,there is a linear relationship between integral fluorescence intensity and quality of CPT.The regression equation was A=474.0+159 881.2 m(μg） with a correlation coefficient of 0.998.The spiked recovery of CPT was 99%.In the quality range of 0.003 3-0.033 0 μg,a linear relationship between integral fluorescence intensity and quality of 10-HCPT was observed,and the regression equation was A=51.3+59 486.2 m(μg） with a correlation coefficient 0.999.The spiked recovery of 10-HCPT was 96%.This method was simple and repeatable.Using this method,the contents of CPT and 10-HCPT in a CCF sample were determined to be 0.122% and 0.013%,respectively.关键词：traditional Chinese medicine;common camptotheca fruit;camptothecine;10-hydroxycamptothecine;TLC-fluorescence scanning
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- 1080
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发布时间： - 摘要：An HPLC method was developed for the determination of acid yellow 36,pigment red 53∶1,pigment orange 5,sudan Ⅱ and sudan Ⅳ in cosmetics.The extraction conditions of five prohibited coloring agents in cosmetic samples,including wax,powder and liquid,were investigated.Using tetrabutylammonium hydroxide as an ion-pair reagent,the optimum chromatographic conditions of the prohibited coloring agents were investigated.The optimal conditions were as the follows:stationary phase：Hypersil C18（4.6 mm×250 mm,5 μm）,mobile phase：acetonitrile(A）-0.01 mol/L tetrabutylammonium hydroxide and 0.01 mol/L citric acid(pH 8.2,B）,flow rate：1.0 mL/min,column temperature：30 ℃ and detection wavelengths：416,484,514 nm.The calibration curves of five prohibited coloring agents showed good linearities in the range of 0.2-50 mg/L with correlation coefficients more than 0.999 and LODs（S/N=3） of 0.2-0.5 mg/L.The five prohibited coloring agents were verified by HPLC-MS/MS.At three spiked levels,the average recoveries were between 85% and 102%,with relative standard deviations of 0.5%-3.6%.The method was accurate,simple and rapid,and could be used to determine acid yellow 36,pigment red 53∶1,pigment orange 5,sudan Ⅱ and sudan Ⅳ in cosmetics.关键词：prohibited coloring agents;cosmetics;HPLC;HPLC-MS/MS
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发布时间： - 摘要：Double perovskite Pr2NiMnO6 was prepared by solid state reaction.Single phase of Pr2NiMnO6 was concluded by X-ray diffraction.The valence state of Ni/Mn and the ferromagnetic behavior were analyzed by X-ray photoelectron spectroscopy(XPS) and magnetism measurement system，respectively.The results indicated that Ni/Mn are mainly divalent/tetravalent and the strong ferromagnetism of Pr2NiMnO6 obtained by magnetic measurements at low temperature is attributed to predominant Ni2+-O-Mn4+ rather than Ni3+-O-Mn3+ ferromagnetic superexchange interaction.This study provides an important clue for the exploration of the magnetism origin of La2NiMnO6.关键词：double perovskite;X-ray photoelectron spectroscopy;valence state;ferromagnetism;superexchange interaction
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发布时间： - 摘要：The characteristics of CoMoP impregnation solution,dried and calcined samples of CoMoP impregnated with γ-Al2O3 were investigated by Raman spectroscopy.Effects of phosphorous content on the structures of the active phases in CoMoP impregnation solution during the impregnation process were studied.The results indicate that the active phases in CoMoP impregnation solution with lower phosphorous content are composed of several heteropoly compounds,such as CoxH6-2x［P2Mo5O23］,CoxH7-2x［PMo11O39］or CoxH3-2x［PMo9O31］and CoxH3-2x［PMo12O40］.CoxH6-2x［P2Mo5O23］is dominant in CoMoP impregnation solution when phosphorous content increases.When the impregnation solution is impregnated into the cavities of γ-Al2O3,higher phosphorous content prevents CoxH6-2x［P2Mo5O23］ from converting to seven poly-molybdate.The presence of tetrahedral and octahedral Mo species is attributed to the interaction between Mo and P in the active phases.关键词：Raman spectroscopy;impregnation solution;active phase
- 1997
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发布时间： - 摘要：A highly selective temperature-responsive molecularly imprinted polymer（MIP） hydrogel to salicylic acid （SA）was prepared by bulk polymerization at 60 ℃,using salicylic acid as template molecule,acrylamide as functional monomer,N-isopropyl acrylamide as temperature-responsive monomer,ethylene glycol dimethacrylate as cross-linker,and azobisisobutyronitrile as the initiator.The lower critical solution temperature（LCST） of molecularly imprinted polymer hydrogels is about 40 ℃.The temperature responsive molecularly imprinted polymer hydrogels showed good selectivity for SA,while non-imprinted hydrogels showed low selectivity,relative to those analogues of SA.The maximum adsorption capacity of the temperature-responsive molecularly imprinted polymer hydrogels reaches up to 6.35 mg/g,which is 3.66 times for that of non-imprinted polymer hydrogels.Compared with the molecularly imprinted polymer without adding temperature-responsive monomers,the adsorption and elution efficiency of the MIP hydrogels with SA were increased by 33.3% and 50%,respectively.Moreover,the temperature-responsive hydrogels could absorb or release SA when the temperature was changed.关键词：Temperature-responsive hydrogels;specific selectivity;molecularly imprinted polymer;adsorption efficiency;release time
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发布时间： - 摘要：In this paper,some high fatty acids in tobacco were analyzed by Ultra-high performance liquid chromatography with evaporative light-scatter detector(UPLC/ELSD).The saponification influence factors of the high fatty acids,including temperature,reaction time,hydrogen ion concentration(pH),volume of extracting agents,etc,were systematically studied through the orthogonal experiments.The best saponification conditions were as follows:saponification temperature:60 ℃,KOH:3 mol/L,CH2Cl2:15 mL,reaction time:60 min.In addition,a new UPLC/ELSD method was established for the determination of six high fatty acids,including linolenic acid,linoleic acid,palm acid,oleic acid,myristic acid and stearic acid in tobacco on the C18 chromatography column by gradient elution with acetonitrile-acetic acid aqueous solution(80∶20,by volume) as mobile phase at a flow rate of 0.3 mL/min,a drift tube temperature of 50 ℃ and a gas flow rate of 2.89 L/min.The linear range of the method was in the range of 42.4 -520.0 mg/L，with detection limits of 3.64-11.98 mg/L.The RSDs(n=7) were in the range of 4.9%-13.5%,and the recoveries ranged from 83% to 104%.This method is rapid,convenient and sensitive,and is suitable for the determination of high fatty acids in tobacco.关键词：orthogonal experiment;UPLC;ELSD;tobacco;high fatty acids
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发布时间： - 摘要：A confirmatory method was developed and validated for the simultaneous determination of four acetylgestagens residues,including flurogestone acetate(FGA),melengestrol acetate(MGA）,megestrol acetate(MA) and chlormadinone acetate(CMA)in ovine milk using high performance liquid chromatography-tandem mass spectrometric(HPLC-MS/MS） method.The analytes were extracted from milk with acetonitrile,defatted with freezing-lipid filtration,and then the extract was purified with C18 solid-phase extraction column.The analytes were analyzed by HPLC-MS/MS in positive multiple reaction monitoring(MRM）mode. Two product ions from each of the chosen precursor ions were acquired for confirmation of the acetylgestagens.Good linearities were achieved with correlation coefficients not less than 0.999 6 for all analytes in the concentration of 0.5-20 μg/L.The limits of detection were 0.2,0.2,0.1,0.1 μg/kg for FGA,CMA,MGA,MA,respectively,with limits of quantitation of 0.5 μg/kg.Recoveries for the ovine milk fortified at levels of 0.5,1.0,2.0,10 μg/kg were in the range of 87%-96%,with RSDs of 4.5%-9.1%.The developed method is sensitive and accurate,and is suitable for the simultaneous detection of these acetylgestagens in ovine milk.关键词：acetylgestagens;ovine milk;residue;high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)
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发布时间： - 摘要：A method was developed for the simultaneous determination of 7 antioxidants，including butylated-hydroxyanisole(BHA),butylated-hydroxytoluene(BHT),tertiary-butylhydroquinone(TBHQ),propyl-gallate(PG),octyl-gallate(OG),iso-amyl-gallate(IAG) and dodecyl gallate(DG),in food using high performance liquid chromatographic(HPLC) method.The liquid oil sample was extracted with methanol.The extract was dried under N2 and redissolved with methanol.The solid sample was extracted with hexane,and then back extracted by acetonitrile repeatedly.The extract was also dried under N2 and redissolved with methanol.The separation of analytes was performed on an Eclipse XDB-C18 column(250 mm×4.6 mm i.d.,5 μm) by gradient elution using methanol-1.5% acetic acid water solution as mobile phase at a flow rate of 1.0 mL/min.The sample was separated and detected with photodiode array detector(PDA).The qualification analysis was performed by using retention time and UV spectrum，and the quantification analysis was based on the detection wavelength of 280 nm.Good linearities between concentrations of 7 analytes and peak area were achieved over the range of 1-100 mg/L with correlation coefficients(r2) larger than 0.999.The limits of quantitation(LOQs,S/N=10) of 7 analytes ranged from 1.0 mg/kg to 1.5 mg/kg.The recoveries ranged from 79% to 101%, with relative standard deviations(RSDs) less than 7%.The method was successfully applied in the determination of 7 antioxidants residues in foods,such as cooking oil and nuts.The method is accurate,rapid and sensitive,and complys with the regulations for the determination of additives residues in foods．关键词：high performance liquid chromatography(HPLC);antioxidants;food
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发布时间： - 摘要：The organic impurities in TiCl4,including CCl3COCl,CHCl2COCl,CH2ClCOCl,CS2 and CCl4,could be simultaneously determined by infrared spectral analysis due to the obvious differences of their infrared spectral characteristics.However,the traditional infrared liquid cell is not fit for the analysis of TiCl4 sample,because TiCl4 is easily hydrolyzed and could immediately reacts with moisture in the air to form highly corrosive hydrochloric acid smoke.In this paper,a new infrared measuring device with a window film of ZnSe（Ф25 mm×2 mm,7 800-440 cm-1） and a cell of PTFE（optical path：10 mm） was assembled and used in determination of the five organic impurities by the standard addition method.The detection limits of CCl3COCl,CHCl2COCl,CH2ClCOCl,CS2 and CCl4 were 3.159×10-3,1.917×10-3,1.554×10-2,5.707×10-3,3.769×10-1 mg?g-1,respectively.The new infrared measuring device was safe,simple,easily removable,washable and reuseable,and the new method has a good application prospect in the real sample analysis and quality control of refined TiCl4 in titanium sponge.关键词：titanium tetrachloride;organic impurities;infrared spectroscopy;infrared liquid cell;quality control of titanium sponge
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发布时间： - 摘要：A gas chromatographic（GC） method was developed for the determination of 11 benzene and its analogies in correction fluid.The conditions for sample pretreatment and GC were investigated and optimized.The correction fluids were extracted with ethyl acetate.The extracts were centrifugalized and filtrated, and then determined by GC and quantified by the external standard method.The results showed that good linear relationships were found at an wide concentrations range of 1.0-200.0 mg/L for all analytes, with correlation coefficients（r2） of 0.999 2-0.999 9.The limits of detection（LOD） were all 1.0 mg/kg.The spiked recoveries ranged from 90% to 105%, with relative standard deviations（RSD, n=6） less than 6%.The results demonstrated that the method was simple, rapid and accurate.关键词：gas chromatography(GC);correction fluids;benzene homologues;ethyl acetate
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发布时间： - 摘要：A molecularly imprinted polymer for cefotaxime（CTX-MIP） was synthesized by the molecular imprinting technique using cefotaxime（CTX） as template molecule,α-methacrylic acid（MAA） as functional monomer,ethylene glycol dimethacrylate（EGDMA） as cross linking agent.By using the cefotaxime molecularly imprinted polymer as sorbent in solid-phase extraction column,a molecularly imprinted solid phase extraction-capillary electrophoresis（MISPE-HPCE） method was developed for the determination of cefotaxime residue in milk.The results showed that cefotaxime imprinted polymer exhibited a higher selectivity to cefotaxime compared with that of the non imprinted polymer.The linear range of cefotaxime was in the range of 0.5-100 mg/L，and the correlation coefficient was 0.999 4.The recoveries at three spiked concentration levels of 10,50,100 mg/L were 78%,84% and 86%,respectively,with RSDs of 3.5%-4.5%.The limit of detection(LOD,S/N≥3） and the limit of quantitation(LOQ,S/N≥10） were 98.52 μg/L and 329.0 μg/L,respectively.The method could meet the requirements for veterinary drug residue analysis.关键词：molecularly imprinted solid phase extraction;capillary electrophoresis;cefotaxime;milk
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发布时间： - 摘要：The research of chloramphenicol reference material in carps meat as a matrix was investigated.The reference material was prepared by adding chloramphenicol to feeding carps，and the homogeneity and stability of samples were detected by liquid chromatography-tandem mass spectrometry（LC-MS/MS）.A cooperative certification was conducted by 8 laboratories.The property value is 5.23 μg/kg ，and the expanded uncertainty is 0.46 μg/kg as the coverage factor is 3.The result showed that the uniformity of samples was good，and the expiration date of reference material was at least 18 months.The reference material can be used in the quality control of residues detection.关键词：reference material（RM）;certification;property value;uncertainty evaluation;chloramphenicol;fish
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