最新刊期
卷 33 ， 期 7 ， 2014
- 摘要：A monolithic column with the structure of three-dimensional bicontinuous skeleton was prepared by in-situ atom transfer radical polymerization（ATRP） with ethylene glycol dimethacrylate（EDMA） as monomer,methanol and hexane as binary porogenic agents,ethy bromopropionate（EBP） as crosslinker and copper bromide and N，N，N′，N′，N″-pentamethyldiethylenetriamine as the catalystical system.Effects of ratio of crosslinker and catalyst on the structure of the monolithic column were studied in details.The surface and micron through-pore and micro skeleton structure of the monolithic column were characterized by scanning electron microscope（SEM） and mercury intrusion method.Then the monolithic column was further modified through grafting copolymerization of butyl methacrylate initiated by —Br group on the surface of monolith.The modified monolithic column with hydrophobic surface was successfully applied in the separation of three steroid drugs（e.g.hydrocortisone,testosterone and progesterone） and four proteins（e.g.cytochrome C,myoglobin,ribonuclease A and ovalbumin） by reversed phase high performance liquid chromatography（RP-HPLC）.关键词：high performance liquid chromatography（HPLC）;monolithic column;pore control;separation of proteins
- 1852
- |
- 1002
- |
- 3
发布时间： - 摘要：The chromatographic fingerprints combined with chemometric methods including principal component analysis（PCA） and hierarchical clustering analysis（HCA） have been applied to evaluate the quality consistency and stability of Nongsuo Danggui Wan（NDW） and Danggui Pian（DP）,as well as the quality correlation with radix Angelica sinensis raw materials（Danggui）.As Chinese patent drugs containing single ingredient of Danggui,the remarkable differences between NDW and DP in the content and distribution of components in fingerprint chromatograms were observed,mainly due to different processing methods and techniques.However,the chromatographic profiles of the same type of samples were generally consistent though the absorption intensities of some common peaks were different,and the similarity values of the NDW samples to Danggui herb were slightly higher than that of the DP samples.The quality consistency and stability of DP samples from different manufacturers and different batches were better than that of NDW.The quality differences of the different batches of NDW or DP samples from the same manufacturer were small.A few marker peaks among the 24 common peaks in chromatographic fingerprints of Danggui were pinpointed by comparing with the fingerprint chromatograms of Chinese patent drug NDW and DP,which were likely to contribute significantly to the pharmacodynamic activities of Danggui.关键词：HPLC fingerprints;Nongsuo Danggui Wan;Danggui Pian;similarity evaluation;chemometric methods
- 2014
- |
- 1057
- |
- 1
发布时间： - 摘要：A specific molecularly imprinted polymer(MIP) film for the determination of phenobarbital(ＰＢ) was electropolymerized on a glassy carbon electrode using methacrylic acid as functional monomer and ethylene glycol maleic rosinate acrylate(EGMRA) as cross-linking agent.The optimum experimental conditions were explored.Under the optimum experimental conditions,the response performances of the sensor for phenobarbital recognition were investigated by cyclic voltammetry(CV),differential pulse voltammetry(DPV) and electrochemical impedance spectroscopy(EIS).The results showed that the molecularly imprinted film exhibits a quick response, good sensitivity and selectivity to the template molecule phenobarbital.A good linear relationship between DPV current signals and phenobarbital concentration in the range of 8.0×10-7-1.0×10-4 mol/L was obtained,with a correlation coefficient(r) of 0.998 3 and a detection limit(S/N=3) of 5.4×10-8 mol/L.The prepared sensor was successfully applied in the determination of phenobarbital in practical samples with recoveries of 95.7%-105.0%.关键词：phenobarbital(PB);ethylene glycol maleic rosinate acrylate(EGMRA);electropolymerization;electrochemical sensor;molecular imprint technique
- 2477
- |
- 1223
- |
- 5
发布时间： - 摘要：A chemiluminescent enzyme immunoassay（CLEIA） method for the detection of triazophos pesticide residue in agricultural products was developed.Checkerboard method was used to get the working concentrations of the immunoassay.Based on the experiment,the concentration of antibody was selected as 2.0 μg/mL,and the concentration of enzyme labeled hapten was chosen as 0.006 μg/mL.Chemiluminescent enhanced solution（CES） was optimized by L25（56） orthogonal experiment and the optimized conditions for the CES were as follows:percentage of organic solvent （DMF） in the CES:6.4%,buffer:0.01 mmol/L Tris-HCl（pH 9.0）,concentration of luminol:0.6 mmol/L,concentration of H2O2:2 mmol/L,and concentration of 4-IMP:1 mmol/L.The sensitivity for detection was 0.489 ng/mL at a practical working concentration range of 0.16-20.00 ng/mL.The recoveries of triazophos in apple,zucchini,rice,orange,litchi and cabbage samples were in the range of 82.8%-118.4%.The confirmation experiment showed that the analytical result of CLEIA method was in agreement with that of the GC-MS method.The developed CLEIA method could be employed in the screening of triazophos residue in apple,zucchini,rice and other samples．关键词：chemiluminescent enzyme immunoassay;chemiluminescent enhanced solution;triazophos;agricultural products
- 1907
- |
- 1043
- |
- 1
发布时间： - 摘要：A method of chiral separation and determination of acephate and methamidophos enantiomers in tea matrix was developed and validated.The efficiencies of two different commercial chiral columns to separate enantiomers of these two pesticides were evaluated and the gas chromatography condition of the better one（BGB-176） was optimized.After soaked in 1 mL water,the tea samples were extracted with 10 mL acetonitrile and purified with C18,primary secondary amine（PSA） and graphitized carbon black（GCB）,then determined by gas chromatography with the external method.The results showed that the recoveries of acephate and methamidophos enantiomers at three spiked levels of 0.04,0.08,0.40 mg/kg were in the range of 58.3%-66.4% and 50.8%-57.6%,respectively.The relative standard deviations（n=5） were all less than 7%.The limits of detection of these two pesticides enantiomers ranged from 0.003 mg/kg to 0.01 mg/kg.The method is quick,convenient and reliable,and could meet the requirement of analysis.The result also showed that the degradations of acephate and methamidophos in tea garden were enantioselective.关键词：chiral separation;acephate;methamidophos;tea;gas chromatography
- 2782
- |
- 1068
- |
- 5
发布时间： - 摘要：A simple method based on accelerated solvent extraction（ASE） /solid phase extraction（SPE） coupled with gas chromatography-mass spectrometry（GC-MS） was developed for the simultaneous determination of 2-ethylhexyl-2,3,4,5-tetrabromobenzoate（TBB）,1,2-bis（2,4,6-tribromophenoxy） ethane（BTBPE）,bis（2-ethylhexyl） 2,3,4,5-tetrabromophthalate（TBPH） and decabromodiphenylethane（DBDPE） in sediments.Extraction and cleanup of four novel brominated flame retardants in lyophilized sediments were performed by improved accelerated solvent extraction（ASE）,and the concentrated solution was cleanup using Florisil solid phase extraction cartridges with 4 mL hexane,then eluted with 4 mL dichloromethane.The eluents was concentrated under a gentle N2 stream and analyzed by GC-MS.The calibration curves were linear in the range of 20-10 000 μg?L-1 for DBDPE,and 2-1.000 μg?L-1 for the rest of compounds，with correlation coefficients more than 0.995.The instrumental limits of quantitation（S/N≥10） for target compounds were in the range of 0.074-44.4 μg?kg-1.The average recoveries of target compounds at two spiked levels（2,10 μg?L-1） were in the range of 79.5%-119.7%,with relative standard deviations（RSDs） of 2.6%-15.3%.The proposed method was applied in the determination of four novel brominated flame retardants in sediments at six different sediments sampling sites from principal watersheds of Shanghai.All samples were detected to be contain TBB,BTBPE,TBPH and DBDPE,except one sampling site without TBB.The method was simple and sensitive,and could meet the requirements for rapid and accurate determination of four novel brominated flame retardants．关键词：accelerated solvent extraction（ASE）;solid phase extraction（SPE）;gas chromatography-mass spectrometry（GC-MS）;sediments;brominated flame retardants
- 2176
- |
- 1104
- |
- 4
发布时间： - 摘要：DNA methylation level in Apostichopus japonicas tissue was determined by high performance liquid chromatography(HPLC) with ultraviolet detection,and the variations of DNA methylation level in Apostichopus japonicas tissue induced by quinoxaline were studied.The chromatographic conditions were as follows:column:ZORBAX SB-Aq(4.6 mm×250 mm,5 μm),column temperature:30 ℃,detection wavelength:280 nm; flow rate:1.0 mL/min,mobile phase：methanol-7 mmol/L ammonium acetate(7∶93).Under the optimal conditions,the calibration curves were linear in the concentration range of 0.05-1.0 mg/L for 5-methyl deoxidization cytidine(5-dmC) and deoxycytidine(dC),with correlation coefficients of 0.999 9.The detection limits were both 0.05 mg/L.The recoveries were in the range of 90.4%-100.6% and the relative standard deviations were below 4% at spike levels of 0.05,0.25,1.0 mg/L.Apostichopus japonicas tissues DNA were extracted using CTAB and hydrolyzed with enzyme.The 5-dmC and dC were determined using HPLC and the results showed that the DNA methylation level of the quinoxaline groups were lower than that of the control groups.Quinoxaline affected the normal gene expression by changing DNA methylation level,which might be a cause of genetic toxicity.The method could be used for the detection of dC and 5-dmC,thus enabling the evaluation of global DNA methylation.关键词：quinoxaline;Apostichopus japonicas;DNA methylation;high performance liquid chromatography(HPLC)
- 2002
- |
- 925
- |
- 2
发布时间： - 摘要：A label-free immunosensor based on K3［Fe(CN)6］-chitosan-glutaraldehyde conjugate composite as signal indicator was developed for the easy and sensitive detection of carcinoembryonic antigen(CEA).The signal layer and nafion-modified glass carbon electrode(GCE) was used to wrap CEA antibodies.The morphology and electrochemical behaviors of the modified GCE substrates were characterized by atomic force microscopy(AFM) and cyclic voltammetry(CV),respectively.The result indicated that the response magnitudes of the anodic peak current were directly related to the concentration of CEA.A good linear relationship between decrease of current and logarithm of CEA concentration in the range of 0.005-40.0 ng/mL was obtained,with a detection limit of 1.23 pg/mL.The developed approach showed a high selectivity,and could be applied in the detection of CEA in human serum samples.关键词：carcinoembryonic antigen;K3［Fe(CN)6］-chitosan-glutaraldehyde conjugate;label-free immunosensor;cyclic voltammetry
- 2590
- |
- 1068
- |
- 0
发布时间： - 摘要：A method was developed for the determination of rhododendrol（RD） in whitening cosmetics by ultra high performance liquid chromatography（UPLC） coupled with fluorescence detection,and the verification analysis was achieved by LC-MS/MS.The samples were extracted with 5% trichloroacetic acid-acetonitrile mixed solution（70∶30）.After centrifugation and filtration,the analysis of RD was performed by UPLC with a conventional C18 column,using 0.1% formic acid-acetonitrile（75∶25） as mobile phase.Fluorescence detection wavelengths were set at λex/λem=280 nm/315 nm.The verification analysis was performed by LC-MS/MS using water（spiked 0.01% ammonia）-acetonitrile as mobile phase by gradient elution.The electrospray was operated in the negative mode（ESI-） under the multiple reaction monitoring（MRM） mode.A good linearity was obtained in the range of 0.05-1.0 mg/L,with a correlation coefficient（r） of 0.999 6,and the limit of quantitation（LOQ,S/N=10） was 2.5 mg/kg for whitening cosmetics.The recoveries of RD ranged from 86.5% to 103.4% with relative standard deviations（RSDs,n=6） of 1.1% - 3.4% at spiked levels of 5.0,10,25 mg/kg in facial mask,cream,lotion and skin water.This method is simple,rapid and accurate,and is suitable for the detection of RD in whitening cosmetics.关键词：ultra high performance liquid chromatography(UPLC);fluorescence detection;liquid chromatography-tandem mass spectrometry(LC-MS/MS);whitening cosmetics;rhododendrol
- 2202
- |
- 1006
- |
- 2
发布时间： - 摘要：A method was established for the determination of multi-components permeability of liquefied petroleum gas through polyethylene membrane by gas chromatography with a self made permeability apparatus.The method was optimized according to the membrane permeability mechanism as well as the characteristics of gas chromatography(GC),and the infiltration time and purging time were set at 15 min and 15 s,respectively.Good linearities for propane,iso-butane and n-butane were obtained in the range of 1.338-1.982×105,1.719-2.595×105,1.719-2.595×105 ng，respectively，with correlation coefficients（r2） of 0.999 0-0.999 6.The limits of detection for propane,iso-butane and n-butane were 0.472,0.534 and 0.692 ng，and the limits of quantitation were 1.573,1.779 and 2.307 ng,respectively.The relative standard deviations were less than 10% .Temperature was a major factor affecting the osmotic equilibrium and permeability coefficient.Under the same conditions,the permeability coefficient and penetration equilibrium time of the each alkane were different.The experimental results indicated that the developed method was simple,fast,and sensitive for the determination of membrane permeability under a condition of multiple gas coexistence.关键词：mixed gas;membrane material;permeability;gas chromatography（GC）
- 1939
- |
- 949
- |
- 1
发布时间： - 摘要：A hydrophilic interaction liquid chromatographic method was established for rapid screening of thiourea dioxide illegally added in food fillings.0.05% acetic acid was used for ultrasonic extraction of thiourea dioxide in ice water bath.The extraction solution was centrifuged,and the supernatant was tested after filtered through 0.45 μm cellulose micro pore membrane.The target compound was separated on a Venusil HILIC（4.6 mm×250 mm,5 μm） column at 25 ℃,using 0.02 mol/L ammonium acetate（glacial acetic acid adjust pH 4.5）–acetonitrile as mobile phase by gradient elution,and detected with photodiode array detector at 275 nm.The calibration curve showed a good linearity for thiourea dioxide within the range of 6.0-200 mg/L.The limits of detection（LOD）and limits of quantitation（LOQ） for the method were 22.5 mg/kg and 75.0 mg/kg,respectively.The spiked recoveries of thiourea dioxide in food fillings ranged from 92.7% to 107% with RSDs of 0.53%-3.8%.This method was rapid,accurate and repeatable,and was suitable for rapid screening thiourea dioxide in food fillings.关键词：hydrophilic interaction;high performance liquid chromatography（HPLC）;food fillings;thiourea dioxide
- 2229
- |
- 1079
- |
- 2
发布时间： - 摘要：A fluorescent probe,rhodamine 6G hydrazide for hypochlorous acid（HOCl） was facilely synthesized by a one-step reaction，based on the rhodamine structure as the fluorophore and hydrazine as the recognition group.Its structure was characterized by nuclear magnetic resonance（NMR） and mass spectrometry（MS），and its fluorescence properties of HOCl detection were also investigated.The results indicated that the probe displayed a good sensitivity and selectivity to HOCl.Using an irreversible oxidation-reduction reaction，the probe showed a rapid fluorescence enhancement proportional to the amount of HOCl in neutral buffer with a linear range of 2-400 μmol/L and a detection limit of 0.06 μmol/L，and other common reactive oxygen species（ROS） revealed relatively inactive interfences to the detection system.The probe was successfully applied in the determination of HOCl in tap water and fluorescence imaging of HOCl in living HeLa cells.关键词：reactive oxygen species;hypochlorous acid;rhodamine;fluorescent probe;fluorescence imaging
- 2135
- |
- 1125
- |
- 3
发布时间： - 摘要：Effect of 1-butyl-3-methylimidazolium tetrafluoroborate （［BMIM］BF4）on the chromatographic behavior of glycyrrhizin（GL） and its derivatives was studied by adding ionic liquids in mobible phase of reverse phase high performance liquid chromatography（HPLC）.The result showed that the addition of ILs had a superior effect on the determination of GL,glycyrrhetinic acid（GA） and glycyrrhetinic acid monoglucuronide（GAMG） by improving chromatographic peak shape,reducing tailing,increasing peak area and peak height,and enhancing detection sensitivity.In addition，the simultaneous detection time of three substances was greatly shortened,and the detection efficiency was obviously improved.The optimum chromatographic conditions were as follows:separation column:InertSustain C18 （4.6 mm×250 mm i.d.，5 μm）;column temprerature:40 ℃;mobile phase:methanol -1.0 mmol/L ［BMIM］BF4 aqueous solution（81∶19,adjusted pH 3.0 with acetic acid）;flow rate:0.7 mL/min;injection volume:20 μL;detection wavelength:251 nm.The calibration curves showed good linearities over the concentration range of 5.00-100 mg/L for three compounds with correlation coefficients not less than 0.999 8.The detection limits （S/N=3） of GL,GA and GAMG were 0.02,0.04 and 0.09 mg/L,with spiked recoveries of 100.1%,98.0% and 98.2%,respectively.The relative standard deviations（RSD） were in the range of 0.18%-0.43%.The method was used to determine the above three components in GL bioconversion system with satisfactory result.关键词：ionic liquids;［BMIM］BF4;high performance liquid chromatography（HPLC）;glycyrrhizin;glycyrrhetinic acid;glycyrrhetinic acid monoglucuronide
- 2082
- |
- 892
- |
- 3
发布时间： - 摘要：A fluorescence resonance energy transfer （FRET） system between fluorescence carbon dots （CDs,donor） and calcein （CA,acceptor） was constructed,and a novel platform for the sensitive and selective determination of kaempferol （KF） was proposed.It was found that in pH 8.0 sodium hydrogen phosphate-citric acid buffer medium,effective energy transfer from CDs to CA occurred,which resulted in a great enhancement of the fluorescence intensity of CA.Upon the addition of KF,the fluorescence quenching of CA occurred,the change of the CA fluorescence intensity was in good linear relationship with KF concentration.Based on this,a novel fluorescence quenching platform for the determination of KF was constructed.Under the optimum condition,the determination range of KF ranged from 1.0×10-8 mol/L to 3.4×10-6 mol/L with a detection limit of 3.33×10-9 mol/L.The method was applied in the determination of KF in compound honeysuckle particles,with recoveries of 98.4%-103.5% and relative standard deviations（RSD） not more than 2.7%.关键词：carbon dots;calcein;fluorescence resonance energy transfer;kaempferol
- 2407
- |
- 1048
- |
- 6
发布时间： - 摘要：The inclusion interaction between cocaine hydrochloride（CH） and p sulfonated calix［4］arene（SC4A） was investigated by fluorescence and 1H NMR spectroscopy.Influences of pH value,temperature,ionic strength and SC4A concentration were examined in detail.In pH 7.5 Britton-Robinson solution,the fluorescence of CH was dramatically reduced to quench upon the addition of SC4A,revealing the formation of inclusion complexes between CH and SC4A.The stoichiometric ratio was verified to be 1∶1 by the continuous variation method.The binding constant of CH-SC4A complexes was calculated to be 6.93×104 L/mol by the nonlinear curve fitting method.1H NMR spectra showed that the bridge ring moiety containing N—CH3 of CH may partially penetrate into the hydrophobic cavity of SC4A.This was confirmed by density functional theory calculations.关键词：cocaine hydrochloride;p-sulfonated calix［4］arene;spectrofluorometry;density functional theory;1H NMR spectroscopy
- 1854
- |
- 931
- |
- 0
发布时间： - 摘要：A rapid method for detection of pentachlorophenol(PCP) residue was established based on gold immunochromatography assay.The colloidal gold strip for PCP was developed successfully.Colloidal gold particles with a size of 20 nm were prepared by trisodium citrate disoxidation method.PCP and anti-mouse goat immunoglobulins were jet-positioned onto a nitrocellulose membrane.Nitrocellulose membrane,gold jet pad,sample pad and absorbent paper were assembled and cut into detecting card,respectively.Through the strip color shades,the detection of PCP residue samples was performed.The detection limit of the colloidal gold strip was 10 ng/mL for PCP in 5 min,and that all needed reagents were included in the strip.This method is characteristic of simplicity,high sensitivity and low cost to achieve the rapid detection of PCP residue.关键词：pentachlorophenol(PCP);colloidal gold;immunochromatography
- 2427
- |
- 1052
- |
- 5
发布时间： - 摘要：A simple and sensitive aptamer-based colorimetric detection of 17β-estradiol was developed using unmodified gold nanoparticles（AuNPs） as colorimetric probe.It is based on the fact that aptamer can be absorbed onto the surface of AuNPs by electrostatic interaction and then the adsorbed aptamer can protect AuNPs against salt-induced aggregation.Upon the addition of 17β-estradiol,the aptamer combined with its target and dissociated from the surface of AuNPs,thus causing AuNPs aggregation under high-salt conditions and the color of such AuNPs solution changed from red to blue.In a typical experiment,the 50 μL 1 μmol/L 17β-estradiol’s aptamer solution and 50 μL AuNPs were added into microplate well and incubated for 5 min.Then 50 μL different concentrations of 17β-estradiol was added to increase a volume up to 150 μL,homogenized and allowed to stand for 5 min.Subsequently,10 μL 2 mol/L NaCl was transferred to the solution to give a final volume of 160 μL and mixed thoroughly.After the solution was equilibrated for 5 min,the UV absorbance spectrum of the solution in the range of 450-750 nm was obtained by UV/Vis spectroscopy.The results showed that,with increase of 17β-estradiol concentration,the color of the solution changed from red to blue and the ratio of OD620/OD520 was increased.As low as 10 ng/mL 17β-estradiol could be detected.In order to determine the specificity of this method,the sensing platform against several non-specific targets was tested.The structural analogues such as estriol,estrone,19-nortestosterone could also cause the color of the solution changing from red to blue with high concentration.while in the presence of other estrogen like matters（such as diethylstilbestrol,bisphenol A and the solvent of methanol）,the solution would still keep red even under high concentration.The results showed that the developed method has high specificity.All of these results illustrated that the method could be readily extended toward the on-site monitoring of 17β-estradiol in environmental matrices.关键词：aptamer;gold nanoparticles;colorimetry;17β-estradiol
- 2283
- |
- 1009
- |
- 9
发布时间： - 摘要：A determination method for purity of creatinine was developed through qualitative analysis,quantitative analysis and uncertainty evaluation.The chemical composition of creatinine sample was determined by liquid chromatography-tandem mass spectrometry(LC-MS/MS) and nuclear magnetic resonance spectrometry(NMR) at first,and then the certified value was studied by mass balance method(including analysis of liquid chromatography,water content,ash content,volatile material and inorganic elements) and quantitative nuclear magnetic resonance(qNMR) method as well.The certified value of creatinine was 99.7%,with the expanded uncertainty of 0.4%.The research is important for correct diagnosis and treatment since it could assure the accuracy of determination of creatinine in Lab.The certified value of creatinine was so far as to use as the internal standard for qNMR.A certified reference material(CRM) for purity of creatinine was developed after homogeneity and stability study.关键词：creatinine;purity certifying;mass balance method;quantitative nuclear magnetic resonance(qNMR)
- 1986
- |
- 977
- |
- 7
发布时间： - 摘要：Electronic nose has become one of the most popular means for rapid detection in tobacco industry,for its advantages of simple operation,easy sample preparation,fast analysis and wide application.In this paper,the working principles,classifications of electronic noses based on the types of sensors were introduced,and the applications of electronic nose in tobacco industry were summarized.Finally,the development trends of electronic noses were discussed.关键词：electronic nose;tobacco;sensors;review
- 1889
- |
- 988
- |
- 2
发布时间： - 摘要：In industrial fields,there are important applications of ultra high purity（UHP） gas,which surely need the technical support with high sensitivity detection methods of trace impurities.For this challenge,the most effective technique is atmospheric pressure ionization mass spectrometry（APIMS） with high sensitivity 104-106 times higher than that of conventional electron impact mass spectrometry（EIMS）.In this article,the emergence,development and ionization principle of APIMS were introduced.Also,the previous research work in analysis of UHP gas by APIMS was reviewed.The specific contents for variety of matrix and impurity gases,the impurity detection limit and the detection method for specific impurities were included.The detection limits of the impurities were more emphasized in this article as the sensitivity is a key point to the purity analysis on UHP gas.关键词：APIMS;ultra high purity gas;purity;impurity;analysis
- 1960
- |
- 1038
- |
- 1
发布时间：
- Address：100 Xianlie Middle Road, Guangzhou Postal code：510070
- Tel：020-87684776,37656606 Fax：020-87684776 Email：fxcsxb@china.com
- Technical support is provided by Beijing Founder electronics co., LTD 粤ICP备12017312号-3
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0