最新刊期
卷 35 ， 期 4 ， 2016
- 摘要：New molecularly imprinted polymers(MIPs)for recognizing four tropane alkaloids(anisodine,scopolamine,anisodamine,atropine) were synthesized by precipitation polymerization using anisodine(ASD)as template,methacrylic(MAA)as functional monomer,trimethylolpropane trimethacrylate(TRIM)as crosslinker and acetonitrile as porogen.The optimal functional monomer and the ratio were selected by UV spectrum method.Comparative determination of the prepared MIP and NIP were carried out by equilibrium adsorption experiment.The results showed that the MIPs possessed the analogous-specific adsorptivity toward four TAs.Scatchard anilysis displayed that the apparent maximum binding capacities(Qmax) are 7.53,10.90,24.27,11.04μg/mg, respectively, and relative selectivity coefficients(IF) are 3.58，1.49，1.62，2.25,respectively.By using the MIPs as sorbent in solid-phase extraction column,a molecularly imprinted solid phase extraction combined with high performance liquid chromatographic(MISPE-HPLC) method was developed for the high performance enrichment and fast separations of four TAs in Przewalskia tangutica Maxim..Good linear calibration curves were obtained in the concentration range of 2-250μg/mL(r2≥0.9999) with LODs of 0.26-0.39μg/mL.The method gave excellent recoveries(70.0%-96.3%) and precision(RSDs≤5.7%,n=3) at 10,50,100μg/g spiked levels.The results indicated that the molecularly imprinted solid-phase extraction(MISPE)with slight matrix interference,highly repeated usage and expectant separation effect,greatly improved extraction efficiencies for four TAs in Przewalskia tangutica Maxim..关键词：molecularly imprinted polymer(MIP);HPLC;solid-phase extraction(SPE);tropane alkaloids;Przewalskia tangutica Maxim.
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- 5
发布时间： - 摘要：A method was established to determine simultaneously the residues of 21 harmful organic solvents in leather and leather products by gas chromatography-mass spectrometry in selected ion monitoring mode（GC-MS/SIM）.Residual harmful organic solvents in leather and leather products were ultrasonically extracted at 45℃,using ethyl acetate as extraction solvent.The extracts were purified with solid-phase extraction（SPE） columns,and then analyzed by gas chromatography-mass spectrometry in selected ion monitoring mode（GC-MS/SIM）.The content of each analyte was calibrated by the external standard method.At the condition of signal to niose（S/N） of ten,the limits of quantitation（LOQs） were 50μg/kg for ethylene glycol dibutyl ether（EGDBE）,triethylene glycol dimethyl ether（TEGDME）,diethylene glycol butyl ether（DEGBE） and triethylene glycol ethyl ether（TEGEE）,150μg/kg for N-methylformamide（MF） and N-methylacetamide（MA）,300μg/kg for formamide,and 100μg/kg for all the other fourteen compounds.The spiked average recoveries varied from 82.1% to 94.9% at three spiked levels with relative standard deviations（RSD） of 1.6%-4.8%.The proposed method was simple,rapid,accurate and sensitive,and was suitable for the determination of residual harmful organic solvents in leather and leather products.关键词：ultrasonic extraction;gas chromatography-mass spectrometry（GC-MS）;selected ion monitoring（SIM）;leather;glycol ethers;amides;N-methylpyrrolidone
- 2182
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- 1207
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- 3
发布时间： - 摘要：Using Mo-Ni-NH3 as impregnation solution,the penetrating mesoporous Mo-Ni-NH3/γ-Al2O3 catalyst was prepared by nano self-assembly technique.The influence of dosage of different surfactants such as CTAB, OP-20, TW-80, OP-10, assistantagentia TEA and NS on dispersity and pore structure of catalyst in the process of self-assembly was investigated by BET,in-situ FTIR of adsorbed CO,XRD and TEM.The results showed that the modified catalyst TOP-3 was better than the others,which has a specific surface area of 183m2?g-1,a pore volume of 0.46m3?g-1 and an average pore size of 10.11nm,and its pore distribution of 10nm-30nm was greatly concentrated, and reached up to 35.63%.The adsorption of active site of Mo2+,Mo4+ and Ni2+ was at the presence of linear adsorption state which could be proved by the in-situ FTIR of adsorbed CO.There were four characteristic crystal plane diffraction peaks of(111),(102),(021) and (312) for Al2(MoO4)3 at 15.9°,20.8°,22.2° and 30.8° by the XRD analysis for NOP-3 and NOP-4.While the fact that the characteristic peaks of TOP catalysts were dispersive showed that the composites of TEA and OP-20 improved the dispersity obviously.The penetrating mesoporous structures in uniform dispersion between 15nm and 20nm could be obtained by TEM images.The structure features were beneficial to residue hydrotreating.关键词：surfactant;mesoporous catalyst;self-assembly;pore structure;characterization
- 1956
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- 1055
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- 2
发布时间： - 摘要：Two analytical methods for the simultaneous determination of 20 pesticide residues in rice were proposed.The rice samples were initially extracted with acetonitrile（MeCN）， then cleaned up by C18 SPE column（method 1） and QuEChERS method（method 2），respectively. The extract was analyzed by GC-MS/MS under selective reaction monitoring（SRM） mode，in which the pesticides were identified by retention time，selected ions and their relative abundances，and quantified by the external standard method.The results indicated that the linear ranges of pesticides were between 0.01μg/mL and 0.2μg/mL，with correlation coefficients all above 0.99.At three spiked concentration levels（ 0.01，0.05,0.20mg/kg），the average recoveries of 20 pesticides in rice purified by method 1 ranged from 63.3% to 96.0%，with relative standard deviations（RSDs） of 1.9%-13.9%.The average recoveries of 20 pesticides in rice purified by method 2 ranged from 67.7% to 121.0%,with RSDs of 1.9%-16.4%.The results showed that there was no obvious difference between two pretreatement methods，and this study provided a different pretreatment way for pesticide residue detection.The proposed method was suitable for the simultaneous determination of multiple pesticide residues in rice.关键词：rice;pesticide residues;gas chromatography-tandem mass spectrometry（GC-MS/MS）;QuEChERS;solid phase extraction（SPE）
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- 1259
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- 7
发布时间： - 摘要：The fragmentation mechanisms of pyridine compounds in extractive atmospheric pressure chemical ionization mass spectrometry（EAPCI-MS） analysis were investigated.The experiments showed that under the ambient conditions，the protonated molecular ion peak［M+H］+ and molecular ion peak M+? could be simultaneously observed using the EAPCI-MS,and similar fragmentation rules can be obtained for their collision induced dissociation（CID） ，without any sample pretreatment and supporting reagent.It is obvious that,compared with that of the traditional ion sources，the chemical selectivity and qualitative analysis of EAPCI source are significantly improved for the rapid detection of pyridine compounds，in which the EAPCI source has both the fragment characteristics of traditional ion sources of ESI and APCI.This study provided a novel method for the qualitative detection of pyridine compounds.关键词：extractive atmospheric pressure chemical ionization mass spectrometry（EAPCI-MS）;pyridine compounds;fragmentation rules;rapid detection
- 2187
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- 1169
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- 1
发布时间： - 摘要：The volatile compounds in the fruit of Liquidambar formosana Hance were investigated by headspace solid phase microextraction with gas chromatography-mass spectrometry（HS-SPME/GC-MS）.The conditions for HS-SPME were optimized by an orthogonal experimental design.Principal component analysis(PCA) and hierarchical clustering analysis were performed to distinguish the samples from different regions.The optimized extraction conditions were as follows：1.0 g of sample extraction using PDMS-DVB fiber for 40 min at 80 ℃，and a desorption time of 1 min.48 volatile compounds were identified in samples from eight geometrical origins.The compound types from different regions were roughly the same while the compound amounts varied with the origins.The two chemometrics methods suggested that the volatile components of L.formosana fruits originated from Hunan，Jiangsu，Sichuan and Liaoning were similar but differed greatly from that from Guizhou，Guangxi，Anhui and Hebei.The PCA results showed that caryophyllene oxide，δ-cadinene and nerolidol could be used as the representative volatile compounds for distinguishment of samples from different regions.The results demonstrated that the HS-SPME/GC-MS method was efficient in identifying volatile components in traditional Chinese medicine.In addition，by coupled with suitable pattern recognition techniques，the method was also powerful in distinguishing the geographical origins of the herbs，which was helpful for quality control of the medicines.
- 2278
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- 6
发布时间： - 摘要：A method was developed for the simultaneous determination of four benzotriazole UV stabilizers（BUVSs） including UV-350,UV-320,UV-328 and UV-327 in textiles by ultra high performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS） combined with ultrasonic extraction（USE）.The samples were extracted with acetonitrile saturated with n-hexane under ultrasonic assistance.The separation was performed on an Eclipse Plus C18 column（2.1 mm×50 mm,1.8 μm） using 0.01 mol/L ammonium formate-methanol as mobile phase.Identification and quantification were achieved by UPLC-MS/MS coupled with electrospray ionization（ESI） source in positive ion mode and multiple reactions monitoring（MRM） mode,and the concentration of each analyte was calibrated by the external standard method.The result indicated that the calibration curves of four BUVSs showed good linear relationships between peak areas and certain concentration ranges with correlation coefficients（r2） greater than 0.99.The limits of detection for UV-350,UV-320,UV-328,UV-327 were 0.023,0.024,0.006 3,0.021 mg/kg,respectively.The limits of quantitation were 0.078,0.081,0.021,0.072 mg/kg,respectively.The recoveries at three spiked concentration levels were in the range of 80.0%-102.9% with relative standard deviations（RSDs） of 1.2%-9.9%.The developed method was successfully applied in the determination of BUVSs in textiles.关键词：ultra-high performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）;benzotriazole UV stabilizers（BUVSs）;textiles;ultrasonic extraction（USE）
- 2003
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- 1159
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- 0
发布时间： - 摘要：An isotope dilution high performance liquid chromatography-tandem mass spectrometric（HPLC-MS/MS） method was established for the determination of biurea in flour and flour products.The biurea in certain matrices was extracted with ultrapure water,defatted with n-hexane when necessary,and then analyzed by HPLC-MS/MS.LC separation was performed on a Waters XBridge BEH Amide column（3.5 μm，4.6 mm×150 mm） using ultrapure water and acetonitrile as mobile phase by gradient elution.Identification was achieved by electrospray ionization（ESI+） in positive mode using multiple reaction monitoring.Quantification was performed by isotope labeled 13C2,15N2-biurea internal standard calibration.The calibration curve of biurea showed a good linearity in the range of 0.2-100 μg/L with a correlation coefficient of 0.999 9.The average recoveries of biurea in flour,steamed bun,bread,deep-fried dough stick and noodle matrices（six aliquots for each level） at three spiked levels ranged from 82.0% to 113.6%,with RSDs of 2.1%-9.3%.The LOQ of the methed was 20 μg/kg.The optimized method was successfully applied in the analysis of 136 real samples collected from local markets in Southern China，while biurea residues were found in 42（30.88%） samples,of which 43.7-564 μg/kg of biurea existed in 4 flours,70.8-9 840 μg/kg in 2 noodles,2 480 μg/kg in 1 deep-fried dough stick,27.4-8 730 μg/kg in 15 breads-crust and 64.3-18 100 μg/kg in 20 breads-interior.This method is applicable for the determination of biurea in flour and different flour products due to its operation convenience,high sensitivity and good accuracy.关键词：high performance liquid chromatography-tandem mass spectrometry（HPLC-MS/MS）;isotope labeled internal standard;flour;flour products;biurea
- 1952
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- 1149
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- 3
发布时间： - 摘要：In this paper, a facile one-step approach to synthesize DNA-templated Ag/Pt bimetallic nanoclusters was developed.The obtained DNA-templated Ag/Pt bimetallic nanoclusters(DNA-Ag/Pt NCs) with diameters about 2-4 nm display a high efficient peroxidase-like catalytic activity,which can catalyze hydrogen peroxide(H2O2) mediated oxidation of the substrate,3,3′,5,5′-tetramethylbenzidine(TMB),to produce a blue color reaction.Based on this,the hairpin structure of thymine-Hg2+-thymine(T-Hg2+-T) interaction was utilized to design an unlabeled DNA electrochemical sensor for the Hg2+detection with high sensitivity and selectivity.Under the optimum conditions,the sensor showed a good linear relationship in the range of 0.65-3.5 nmol/L with a detection limit as low as 0.17 nmol/L and also exhibited an ultra high discrimination ability for Hg2+.All above properties make the sensor a promising candidate for Hg2+trace detection in real water samples.关键词：DNA template;bimetallic nanoclusters;mimic enzyme;mercury(Ⅱ);electrochemical sensor
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- 4
发布时间： - 摘要：An analytical method was developed for the simultaneous determination of 12 banned dyes（basic orange 2，basic orange 21，basic orange 22，dimethyl yellow，ethyl yellow，sudan orange G，auramine O，solvent yellow 124，orangeⅡsodium salt，metanil yellow，acid yellow 11 and allzarin yellow R） in soy products by ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）.Soy products samples were extracted using acetonitrile acidified with acetic acid.After frozen for 2 h under-20 ℃，the extracts were centrifuged to reduce lipids and other related interference.The target compounds were separated on an ACQUITY UPLC- BEH C18 column by means of a binary mobile phase gradient with water containing 0.1% ammonium hydroxide formic acid and acetonitrile for 4 dyes（orangeⅡsodium salt，metanil yellow,acid yellow 11 and allzarin yellow R） and 0.1% formic acid and acetonitrile for the other eight compounds.Mass spectrometric acquisition was carried out by means of multiple reaction monitoing（MRM） under negative ionization mode for 4 dyes and positive mode for the rest of target compounds，respectively.As a result，quantitation limits of 12 dyes in soy products samples were in the range of 0.2-10.0 μg/kg.Mean recoveries at three spiked levels ranged from 76.2% to 122.0%，and the relative standard deviations（RSDs）were between 1.1% and 7.4%，which complied with the regulations for the determination of trace contaminants residues in food matrix.Simultaneous extraction and purification of 12 dyes in soy products matrix was achieved upon the established method which could be applied in the routine detection of illegally additive dyes in soy products due to its simplicity and high sensitivity.关键词：ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）;dyes;soy products
- 2120
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- 1141
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- 8
发布时间： - 摘要：A rapid method was developed for the determnation of 4 thiurams vulcanization accelerators,tetrabenzyl thiuram disulfide(TBZTD),dimethyldiphenylthiuram disulfide(TMD),thiram D12 and dicyclopentamethylenethiuram disulfide(DPTD) in rubber products by ultra performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS).Rubber samples were diluted in methanol and extracted by ultrasonic.After centrifugation and filtration,the target compounds were separated on a reversed phase C18 column with a mixture of methanol and water as mobile phase,analyzed by UPLC-MS/MS and quantified by the external standard method.Separation of the target substances in different chromatographic conditions was investigated,and effects of different extraction solvents on extraction effienciency were investigated.Under the optimal conditions,the calibration curves for TMD,thiram D12,TBZTD and DPTD were in good linearity in the ranges of 0.002-1.000,0.002-1.000,0.100-10.000, 0.020-10.000 mg/L,respectively,with limits of quantitation of 0.001 0,0.001 2,0.100 0,0.020 0 mg/L,respectively.Recovery tests were made by the addition of standards to blank sample at different concentrations,and the recoveries were in the range of 82.7%-98.8% with relative standard deviations(RSDs,n=5) of 4.6%-7.0%.The method is simple,rapid and sensitive,and could meet the requirements for detection of TBZTD,TMD,Thiram D12 and DPTD in rubber products.关键词：thiuram;vulcanization accelerator;rubber products;ultra performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS);detection
- 2035
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- 1051
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- 4
发布时间： - 摘要：A rapid analytical method based on gas chromatography-mass spectrometry(GC-MS) was established for the simultaneous determination of eight polycyclic aromatic hydrocarbons(PAHs) in textiles.PAHs in the samples were extracted with hexane-acetone(1∶1) by ultrasonic technique,followed by concentrated with nitrogen.The separation was performed on a DB-17MS capillary column with temperature programming.The identification was performed by GC-MS in selected ion monitoring(SIM) mode,and the quantification was carried out by the external standard method.The processes of extraction were investigated,and the GC-MS parameters were optimized.The calibration curves of eight PAHs showed good linearities in the ranges of 0.05-1.00 mg/L or 0.10-1.00 mg/L with correlation coefficients(r2) larger than 0.995.The limits of detection(LOD) of PAHs in textiles ranged from 0.02 mg/kg to 0.05 mg/kg and the limits of quantitation(LOQ) ranged from 0.05 mg/kg to 0.10 mg/kg.The average recoveries of eight PAHs at three spiked concentrtion levels were in the range of 81.2%-106.4% with relative standard deviations(RSDs,n=6) of 2.5%-8.5%.The method was suitable for the simultaneous determination of eight PAHs in textiles with high accuracy,easy operation and good precision.关键词：gas chromatography-mass spectrometry(GC-MS);textile;polycyclic aromatic hydrocarbon;determination
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- 1113
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- 2
发布时间： - 摘要：An analytical method was developed for the determination of carotenoids and their isomers in tomatoes by an improved high performance liquid chromatography（HPLC） method.Hexane-ethanol（3∶4） was chosen as the best solvent system for extracting carotenoids from tomatoes by stirring 30 min using a magnetic stirring apparatus.11 kinds of carotenoids including all trans forms of lycopene，β-carotene，lutein and 8 kinds of cis-isomers were completely separated in 30 min on a Carotenoid C30 column（250 mm×4.6 mm i.d.，5 μm particle） using methyl tert-butyl ether（MTBE） containing 0.05% triethylamine（TEA） as mobile phase A and acetonitrile containing 0.05% TEA as mobile phase B by gradient elution.The flow rate was set at 1.0 mL/min，and the detection wavelength was 475 nm.For lutein，β-carotene and lycopene，the calibration curves were linear in the ranges of 0.1-5.0，0.1-20 and 0.1-100 μg/mL,respectively，with correlation coefficients more than 0.99.The limits of detection（LOD） were 0.13，0.12,0.56 μg/g，respectively，the limits of quantitation（LOQ） were 0.43，0.41,1.88 μg/g，respectively.The intra-day relative standard deviation（RSD） were in the range of 1.2%-5.3%，and the inter-day RSDs were 1.9%-7.5%.The recoveries were in the range of (88.9±6.1)%-(91.7±3.6)%，(92.3±4.3)%-(94.1±6.3)% and （102.6±4.2）%-(107.1±3.4）%，respectively.This HPLC method could be used to separate 11 types of carotenoids in tomatoes completely with a short time and high sensitivity.关键词：high performance liquid chromatography（HPLC）;carotenoids;cis isomers;tomato
- 1976
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- 1093
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- 2
发布时间： - 摘要：Gas chromatography（GC） was used to determinate the composition and contents of fatty acids in vegetable oils,including olive oil,peanut oil,rapeseed oil and soybean oil.And the GC fingerprint profile was employed for the fingerprint analysis and species classification of the four species of vegetable oils.11 feature variables were selected by successive projections algorithm（SPA）.Then,principal component analysis（PCA） and three supervised pattern recognition models:radial basis function artificial neural natwork（RBF-ANN）,least square-support vector machine（LS-SVM）,and linear discriminant analysis（LDA） were established to predict the species of the vegetable oils.The result demonstrated that the PCA obtained a clear clustering of objects respect to the species.RBF-ANN model performed better than the other two supervised pattern recognition models,with classification rate of 92.6%,and could predict the two component mixed oil sample accurately.The method could be used to distinguish the species of vegetable oil,and might be applicable for the identification of edible vegetable oils.关键词：vegetable oils;olive oil;gas chromatography（GC）;fingerprint;chemometrics;distinguish
- 2124
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- 1123
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- 6
发布时间： - 摘要：An ultra performance liquid chromatography-tandem mass spectrometric（UPLC-MS/MS） method was developed for the simultaneous determination of steroid hormones in ovaries of zebrafish.Homogenized ovary samples were purified with NH2 and HLB solid phase extraction column after extracted with acetonitrile and ethyl acetate at 4 ℃.The samples were transported and eluted on an analytical column ACQUITY UPLC-BEH C18（2.1 mm×100 mm,1.7 μm）.All the analytes were detected in selected reaction monitoring（SRM） mode and quantified by the external matrix-matched standard method.The extraction efficiencies of different extraction solvents and cleanup effects of solid phase extraction columns for each analyte were further investigated.The average recoveries of 13 steroid hormones in spiked zebrafish ovary samples ranged from 74.8% to 127.0% with relative standard deviations（RSD） of 3.9%-15.8%.The results showed that the limits of detection（LODs,S/N=3） were in the range of 0.006-0.300 μg/kg.The method was sensitive and reliable,and could meet the requirements for the quantification of steroid hormones in zebrafish at physiological level.关键词：ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）;NH2;HLB;zebrafish;steroid hormones
- 2026
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- 1127
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- 2
发布时间： - 摘要：A method for the simultaneous determination of 5 plant growth regulator residues,including 6-benzyl adenine（6-BA），thidiazuron，forchlorfenuron，paclobutrazol and uniconazole in fruits was developed by using ultra high performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS） with solid phase extraction（SPE）.Samples were extracted with acetonitrile，then the extracts were concentrated and cleaned up on a NH2 solid phase extraction cartridge with dichloromethane-methanol（92∶8） as elution solution.Sample preparation was accomplished after concentrated and redissoved.The UPLC-MS/MS method was performed with Waters ACQUITY UPLC BEH C18（50 mm×2.1 mm，1.7 μm） column using water-methanol as mobile phase by gradient elution，at a flow rate of 0.3 mL/min.The target compounds were determined by UPLC-MS/MS under multi reaction monitoring（MRM） mode，and then quantitatively analyzed by external standard method using the matrix-matched standard solution.The results showed that there were good linearities for 5 plant growth regulators between peak areas and concentrations in the range of 5-500 ng/mL under the optimal conditions，with correlation coefficients（r2） of 0.996 1-0.999 6.The spiked recoveries of 5 plant growth regulators in fruits at three spiked levels of 0.004，0.02，0.1 mg/kg ranged from 75.6% to 110.5% with relative standard deviations（RSDs） of 1.2%-12.8%.The limits of detection of this method（LOD） were in the range of 0.001-0.002 mg/kg，and the limits of quantitation（LOQ） were 0.003-0.006 mg/kg.The established method was simple，sensitive，accurate and reliable，and could meet the requirements of multi pesticide residues analysis in fruits.关键词：solid phase extraction（SPE）;ultra high performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）;fruits;plant growth regulators
- 2183
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- 1193
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- 4
发布时间： - 摘要：After the derivatization reaction of 8 kinds of essential amino acids(threonine,valine,methionine,isoleucine,leucine,phenylalanine,lysine,tryptophan) in human body with o-phthalaldehyde(OPA),a method of capillary electrophoresis coupled with electrochemical detection(CE-ED) was established for the determination of these eight essential amino-acids.Effects of derivatization time,detection potential,concentration and pH value of running buffer,separation voltage and injection time on the detection were investigated.Under the optimum conditions,a good baseline separation and highly sensitive detection for eight essential amino-acid in yam were achieved in 12 min.The calibration curves of eight essential amino acids were linear in the range of 0.1-1 500 μg/L,with detection limits(S/N=3) of 0.01-0.05 μg/L.The relative standard deviations(RSDs) for peak heights of eight essential amino-acids were in the range of 1.3%-1.8%,and the RSDs for migration times were 0.6%-1.0%.The method was successfully applied in the assay of eight essential amino-acids in samples of yam,with spiked recoveries of 96.8%-102.0% and RSDs not more than 2.4%.关键词：capillary electrophoresis;electrochemical detection;yam;amino-acid
- 2097
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- 1213
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- 4
发布时间： - 摘要：A method was developed for the determination of four pesticides residues in a variety of vegetables using solid phase extraction（SPE） and ultra performance liquid chromatography-triple quadrupole-mass spectrometry（UPLC-MS/MS）.The purification methods（solid phase extraction column,QuEChERS method,elution solvent,elution volume）,chromatographic conditions（mobile phase type,flow rate and column temperature） and mass spectrometric parameters（fragment,delta EMV） were optimized.The pesticides samples were extracted with acetonitrile,and then cleaned up on a Carbon/NH2（or NH2） SPE column.The eluting solution was evaporated and made up to a definite volumn with methanol,finally analyzed by reversed phase ultra performance liquid chromatography under multiple reaction monitoring（MRM） of positive ion mode with the external standard method.The calibration curves of four pesticides showed good linearities in the range of 5-500 μg/L with correlation coefficients not less than 0.999 2.The limits of detection（LOD） were in the range of 0.033-0.167 μg/kg and the limits of quantitation（LOQ） were in the range of 0.10-0.50 μg/kg for 4 pesticides spiked in vegetable.The recoveries of 4 pesticides in vegetable sample spiked with three concentration levels of 10,50,250 μg/kg ranged from 70.9% to 123.4% with RSDs less than 15%.The established method was accurate,sensitive and simple,and was suitable for the simultaneous analysis of various pesticides residues.关键词：ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）;solid phase extraction（SPE）;pesticide residue;vegetable
- 2208
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- 1186
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- 3
发布时间： - 摘要：A C18 reversed phase high performance liquid chromatographic（RP-HPLC） method was developed for the determination of total astaxanthin saponified from Antarctic krill oil.The sample was saponified with sodium hydroxide-methanol solution（4 mol/L），the reaction was ended with sodium hydrogen sulfate,and the reaction liquid was purified by n-hexane liquid-liquid extraction．The effect of saponification time on saponification efficiency of astaxanthin in Antarctic krill oil was investigated.The results showed that the best saponification time was 30 min．Chromatographic separation was performed with a C18 liquid chromatographic column（250 mm×4.6 mm，5 μm） at room temperature with an eluent of 100% methanol at a flow rate of 1.0 mL/min.The eluate was monitored with a diode array detector at 476 nm.The separation and identification of astaxanthin was completed within 5 min.The limits of detection（LOD） and quantitation（LOQ） for astaxanthin in Antarctic krill oil were 0.005 mg/kg and 0.2 mg/kg,respectively.A good linear relationship between chromatographic peak area and concentration in the range of 0.2-20.0 mg/L was obtained with a correlation coefficient of 0.999 9．The average recoveries were between 90.2% and 95.2%，and the inter- and intra-RSDs of the method were not more than 3.4% and 4.3%,respectively.The method was rapid,simple,precise and accurate,and could be applied in the inspection of astaxanthin in Antarctic krill oil．关键词：astaxanthin;Antarctic krill oil;astaxanthin ester;saponification;high performance liquid chromatography（HPLC）
- 2300
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- 1277
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- 3
发布时间： - 摘要：18 infant formula powder samples were analyzed by RP LC-Q-TOF MS,and potential chemical markers were filtered by PCA.Different parameters for pretreatment on the results of data analysis were studied.The characteristic components of partially hydrolyzed protein in infant formula powder were found by T-test.The chemical information of 16 characteristic components in G sample was proposed,and the correspongding chemical fingerprinting was constructed.关键词：chemical fingerprinting;chemometrics;liquid chromatography-quadrupole／time-of-flight mass spectrometry(LC-Q/TOF-MS);infant formula powder
- 1899
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- 1142
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- 0
发布时间： - 摘要：Carbohydrate antigens CA125（Ag） are the most important markers in early stage of tumor and cancer stage.Antibodies Ab125（Ab） to carbohydrate antigens were labeled to form probe-labeled antibodies LP-Ab using the prepared two-photon fluorescence probe LP.On the basis of the antigen-antibody specificity affinity principle，LP-Ab could combine with carbohydrate antigen into a complex LP-Ab?Ag which emitted strong two-photon fluorescence to accomplish the high sensitive biopsy and the real-time dynamic high-resolution imaging of the tumor markers.The easy，simple and quick method could not only overcome photodamage，photobleaching and tissue auto-fluorescence disturbance，but also be used to observe and study the dynamic transfer mechanisms of the tumor markers in cells and the mechanism of carcinogenesis.The research in this project is very useful in the early diagnosis and prevention of tumor and canceration.关键词：CA125;Ab125;immunofluorescence labeling;two-photon;biopsy
- 2115
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- 1125
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- 0
发布时间： - 摘要：A novel chemiluminescence method for the determination of aceclofenac was developed,based on the fact that aceclofenac could enhance the chemiluminescence intensity from the reaction of potassium permanganate with formaldehyde in acidic medium.The experiments indicated that under optimum conditions,the enhanced intensity of chemiluminescence was linearly related to the concentration of aceclofenac in the range of 0.08-5.0 mg／L with a detection limit(3σ) of 3.0×10-2 mg／L.The relative standard deviation(RSD) was 1.7% for 0.50 mg/L aceclofenac solution in 11 repeated measurements.The method was successfully applied in the determination of aceclofenac in the tablets and capsules with recoveries of 981%-104.6%.关键词：flow injection;chemiluminescence;aceclofenac;potassium permanganate
- 2033
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- 1085
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- 2
发布时间：
- Address：100 Xianlie Middle Road, Guangzhou Postal code：510070
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