最新刊期
卷 30 ， 期 4 ， 2011
- 摘要：A novel amperometric immunosensor based on multi wall carbon nanotubes(MWNTs)/ layer by layer(LBL) assembly of gold nanoparticles and thionine(GNPs-THI)/secretory immunoglobulin A(sIgA)/horseradish peroxidase(HRP) was developed for the detection of salivary secretory immunoglobulin A(sIgA). The layer by layer(LBL) assembly of gold nanoparticles and thionine(GNPs-THI) was assembled through electrostatic adsorption, Au-S and Au-N covalent bonds. Then the salivary anti-sIgA antibody was adsorbed by the formative monolayer of GNPs. Eventually, the horseradish peroxidase (HRP) was used to block the nonspecific adsorption sites on the modified glassy carbon electrode (GCE) and amplify the current signal at the same time. The immunosensor showed a high sensitivity to salivary sIgA with a detection limit(S/N=3) of 15 μg/L.The linear range was 3.0-350.0 μg/L with correlation coefficient(r) of 0.989 7.The response time achieved 95% of the steady state was less than 20 s. Also, the immunosensor had an excellent interference immunity to the interferents of immunoglobulin G (IgG), α amylase and albumin, and the interference rates were -2.13%, -2.85% and -196%,respectively. The antigen-antibody complexes in the measurement were decollemented by 0.1 mol/L of aminoacetic acid. The bioactivities of antigen and antibody were remained well after decollement and the biosensor could be recycled by aminoacetic acid for eight times. Some influence factors on the biosensor were investigated, such as the concentration of substrate and antibody, incubation time, interferents, temperature and pH. It can be used for accurate and fast detection of salivary sIgA to judge the impairment of the mucosal immune system of human owing to its high sensitivity, excellent specificity and convenient detection，and it can be easily regenerated.关键词：secretory immunoglobulin A;immunosensor;multi wall carbon nanotubes;thionine
- 2290
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- 935
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- 3
发布时间： - 摘要：Two dimensional difference in gel electrophoresis（2D DIGE） combined with high performance liquid chromatography-nano electron spray ionization tandem mass spectrometric（HPLC-nESI MS/MS） method was developed for the identification of the differentially expressed potential protein markers of human keratinocytes cell HaCaT in response to UVB irradiation,which aims to obtain the target proteins affecting the normal physiological function of skin cells induced by UVB irradiation.The results indicated that UVB irradiation could affect the integrity protein expression profile of HaCaT cell.Over 1 200 protein spots were averagely resolved on each DIGE gel by DeCyder software analysis.41 protein spots were found differentially expressed with statistical significance beyond DIGE detection limit.9 protein spots differentially expressed most significantly were successfully identified by HPLC-nESI MS/MS analysis.4 up regulated protein spots were identified as 26S proteasome subunit p405（PSMD13）,cathepsin D（CTSD）,human co chaperone P23（PTGES3） and 6 phosphogluconolactonase（PGLS）.The other 5 down regulated protein spots were identified as laminin receptor 1（RPSA）,interferon gamma inducing factor precursor（IL18）,calmodulin （CALM3）,protein similar to 60S acidic ribosomal protein P2（RPP2） and breakpoint cluster region protein 1（BANF1）.Only RPSA,CALM3 and CTSD proteins have been reported to be associated with skin burns and wound healing,proliferation and migration of keratinocytes and epidermal barrier repairing process.No study has been reported on the associations of the rest 6 proteins with damages from skin and skin cells.These 9 proteins are potential indicators for skin cells responding to UVB irradiation.The results from the current work provide valuable clues to effective protection for skin diseases at molecular level.关键词：UVB;HaCaT;two dimensional difference in gel electrophoresis;HPLC-nESI MS/MS
- 1875
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- 1086
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- 0
发布时间： - 摘要：A quartz crystal microbalance(QCM) chiral recognition method was used to predict the chiral recognizability of a chiral selector for a racemate.The chiral selector of L phenylalanine(L Phe) was immobilized on the surface of a QCM sensor by a two step assembly procedure.The L Phe modified sensor surface was characterized using several techniques,including resonant frequency detection,the contact angle and X ray photoelectron spectroscopy measurements.The chiral recognizability of the L Phe modified QCM sensor for L mandelic acid(MA) was examined by the vapor diffused molecular assembly reaction technique,and the chiral discrimination factor between L and D MA was obtained to be about 8.The practical diastereomeric crystallization resolution of a MA racemic mixture was then carried out using L Phe as resolving agent.The different properties of the diastereomer crystals of L Phe-L MA and L Phe-D MA were confirmed by HPLC,morphology and DSC detection.The factors influencing the diastereomeric crystallization resolution were investigated.Under the optimal conditions,the results showed that the diastereomeric crystallization separation of racemate MA with L Phe as resolving agent matched well with that by the QCM chiral recognition method.Therefore,the proposed method using QCM chiral recognition can offer a simple solution to the challenge of screening a resolving agent for diastereomeric crystallization.关键词：chiral recognition;quartz crystal microbalance;diastereomeric crystallization;resolving agent;L phenylalanine;mandelic acid
- 2573
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- 1109
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- 2
发布时间： - 摘要：In situ UV-Vis spectroelectrochemical spectra of the electrochemical copolymerization of aniline(AN) and o aminobenzenesulfonic acid(ABSA) was investigated in 01 mol/L HClO4.The homopolymerization of ABSA and AN also arised independently in the same medium.The results indicated that ABSA was firstly oxidized to its cation radical，then a mixed oligomer intermediate was formed by the cross-reaction of ABSA and AN cation radicals with their monomers.The absorption peak at 550 nm in the UV-Vis spectra was assigned to this intermediate.The intermediates then reacted with each other to form the polymer finally.The results also indicated that the polymerization of AN became dominant with the increase of the AN amount in the mixed solutions,which demonstrated that the copolymerization mechanism was related to the concentration ratio of ABSA and AN.Fourier transform infrared spectra also indicated the effective attachment of ABSA on the PAN backbone formed the self doped PAN.关键词：aniline;o aminobenzenesulfonic acid;electrochemical copolymerization;in situ UV-Vis spectroelectrochemistry
- 2070
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- 981
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- 2
发布时间： - 摘要：A gas chromatography-ion trap tandem mass spectrometric（GC-IT-MS/MS） method was established for the determination of 25 organochlorine pesticides（OCPs） and polychlorinated biphenyls（PCBs） in soil and sediment.The sample was extracted with hexane and acetone（1∶1，by volume） by accelerated solvent extraction（ASE），cleaned up by solid phase extraction（SPE）.The MS/MS parameters were systematically investigated and optimized.Under the optimal conditions，the linear ranges of 17 OCPs ranged from 1.73 μg/L to 2208 μg/L（except for endrin from 3.45 μg/L to 441.6 μg/L）,with the method detection limits（MDLs）of 0.049-0.274 μg/kg,and the linear ranges of 8 PCBs ranged from 0.87 μg/L to 110.4 μg/L,with the MDLs of 0.028-0.049 μg/kg.The average recoveries of 25 OCPs and PCBs at two spiked concentration levels of 0.345 μg/kg and 3.45 μg/kg were in the range of 70%-108% with relative standard deviations（RSDs） of 5.0%-14.0%.The method was applied in the determination of 25 OCPs and PCBs in complex soil and sediment samples. The results showed that，compared with the GC-MS method，the IT-MS/MS method could effectively eliminate a large number of interference factor，reduce the possibility of false positive and false negative results，and improve the accuracy of quantitative results.关键词：OCPs;PCBs;GC-IT-MS/MS;soil;sediment
- 2388
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- 1121
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- 15
发布时间： - 摘要：A novel method was developed for the qualitative and quantitative analysis of trace volatile organic compounds(VOCs）,methyl jasmonate and methyl salicylate,emitted from peanut based on a designed dynamic adsorption device coupled with high performance liquid chromatography tandem mass spectrometry(HPLC-MS/MS）.The VOCs were adsorbed with Tenax TA,eluted with methanol solution containing 0.1% formic acid,and concentrated with nitrogen.The separation of the VOCs was carried out on an Agilent C18 column by gradient elution mode using methanol-005% formic acid as mobile phase at a flow rate of 300 μL/min.The samples were analyzed by ion trap mass spectrometer under positive ion mode with multiple reaction monitoring.The internal standard method was used for quantitative analysis.The detection limits(S/N=3） for methyl jasmonate and methyl salicylate were 2.0 μg/L and 20.0 μg/L,and the quantitation limits(S/N=10）were 5.0 μg/L and 50.0 μg/L,respectively.There was a good linear relationship(r>0.98） between the concentration and the peak area ratio in the range of 1.0-500 μg/L for methyl jasmonate and 20-1 000 μg/L for methyl salicylateThe method was simple,rapid and high efficient,and was suitable for the investigation of changes of volatile organic compounds emitted from plant at different treatment conditions.关键词：dynamic adsorption;high performance liquid chromatography-tandem mass spectrometry;trace;volatile organic compounds
- 2305
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- 1179
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- 0
发布时间： - 摘要：Using the characteristics that subcritical water can quantitatively extract a wide variety of organic solutes from different matrixes,12 pesticides were extracted from radish,cantaloupe,apple and cabbage by subcritical water extraction combined with solid phase adsorption in accelerated solvent extractor after adding C18 padding in the cell.The extraction conditions were optimized.The determination of 12 pesticides was performed by gas chromatography-tandem mass spectrometry(GC-MS/MS).The result indicated that the limits of quantitation were in the range of 0.025-0.050 mg/kg,and the recoveries of 12 pesticides from fruits and vegetables samples at spiked level of 0.05 mg/kg were in the range of 62%-110% with RSDs less than 10%.关键词：subcritical water extraction;pesticide residues;solid phase adsorption
- 2598
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- 1154
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- 1
发布时间： - 摘要：An in situ acetylation solid phase microextraction（SPME）/gas chromatography-mass spectrometry was developed for the determination of phenolic compounds in water using central composite designs of the response surface methodology in the process of optimization experiments.Three important response factors,namely derivatization reagent（acetic anhydride）,derivatization agent（Na2HPO4） and reaction/extraction temperature,confirmed by the single factor experiments to be the continuous variables of non monotonic change in the derivatization and extraction processes were selected.Taking the normalized peak area,ie.the dependent variable representing relative extraction efficiency,as the optimizing target,quantitative relationships between the relative extraction amount and the three independent factors were established with the backward multi regression fitting.Results of the variance analysis revealed the regression was significant with the lowest F and P value at 63 and 0002 8,respectively.In addition,the variance analysis indicated that the temperature effect was the most significant,the amount of Na2HPO4 next and acetic anhydride the least. Results also showed that the optimum conditions were quite different for different phenolic compounds,since the reaction / extraction temperatures were related to their boiling points and the Na2HPO4 amount was related to their dissociation constants（pKa）.关键词：headspace solid phase microextraction;acetylate;response surface methodology;phenols;water
- 1979
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- 1061
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- 2
发布时间： - 摘要：A micellar electrokinetic capillary chromatographic(MEKC) method was established for the simultaneous determination of liquiritin,rutin,hyperin,quercitrin,chlorogenic acid and rhein in Lianhuaqingwen Capsule.Effects of experimental conditions,such as pH value,concentration of sodium dodecyl sulfate(SDS),type of organic modifier,concentration of background electrolyte and applied voltage, on separation efficiency of six targeted compounds were optimized.A baseline separation of six components was achieved in 30 min when the samples were separated on an uncoated fused silica capillary column(75 μm×60 cm,effective length 50 cm),using 50 mmol/L SDS-15 mmol/L Na2HPO4-15 mmol/L H3BO3 (containing 25% 2 propanol,pH= 80)as running buffer,with applied voltage of 30 kV.The analytes were detected by UV detection at 254 nm.Under the optimum conditions,the calibration curves were linear in the range of 4.5-120 mg/L for liquiritin,3.0-100 mg/L for rutin,1.5-50 mg/L for hyperin,1.5-100 mg/L for quercitrin,4.5-600 mg/L for chlorogenic acid and 0.90-160 mg/L for rhein with detection limits of 1.5,1.0,0.50,0.50,1.5,0.30 mg/L,respectively.The average recoveries of the six components were between 90% and 108% with all relative standard deviations not more than 4.2%.The developed method was simple,rapid and accurate,and was suitable for the routine analysis of the six effective components in Lianhuaqingwen Capsule.关键词：micellar electrokinetic capillary chromatography;Lianhuaqingwen Capsule;effective component;simultaneous determination
- 2444
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- 1046
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- 2
发布时间： - 摘要：A new fluorescent labeling reagent,1,3,5,7-tetramethyl-8-propionohydrazide difluoroboradiaza s indacene (BODIPY propionohydrazide）,was synthesized for the determination of C1-C12 aliphatic aldehydes by high performance liquid chromatography(HPLC）. The experimental conditions were optimized. In the presence of phosphorous acid as a catalyst，the derivatization reaction of BODIPY propionohydrazide with aldehydes was completed in 30 min at 60 ℃.The stable BODIPY hydrazone derivatives(except for formaldehyde and acetaldehyde derivatives） could be separated in 20 min with acetonitrile（containing 20% tetrahydrofuran） and HCOOH-NH3?H2O as mobile phase（pH=6.5）. Under the optimal conditions,the calibration curves of C1-C12 aliphatic aldehydes were linear in the range of 0.01-2.00 μmol?L-1 with detection limits(S/N=3） of 0.23-0.78 nmol?L-1. The established method was applied in the determination of aliphatic aldehydes in wine samples with spiked recoveries of 95%-105%.关键词：fluorescent labeling reagent;1,3,5,7.tetramethyl.8.propionohydrazide difluoroboradiaza s indacene;aliphatic aldehydes;high performance liquid chromatography;wine
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- 1115
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- 1
发布时间： - 摘要：The dry rhizome of Acorus tatarinowii Schott is a common traditional Chinese medicine and could be used for treatment of lots of diseases,such as epilepsy.In this paper,the volatile constituents of Atatarinowii Schott from 4 growing areas,egAnqing,Anhui;Jinhua,Zhejiang;Songxian,Henan and Zhumadian,Henan,were investigated by gas chromatography-mass spectrometry(GC-MS).Total of 45 volatile constituents were tentatively identified and their relative contents were determined.There were 4 common volatile constituents(β asarone,γ asarone,α asarone and cis methylisoeugenol) in Atatarinowii Schott,which occupied more than 1% of the contents of the volatile constituents.Their retention time and relative contents could be regarded as the essential condition of the identification and quality assessment on Atatarinowii Schott.In application of the dividing sections,the total ion current chromatograms of Atatarinowii Schott were divided into 4 sections and were further compared with the relative retention value(α) and the relative peak area(Sr).It was shown that the 3rd section of the total ion current chromatograms was the major active ingredient of Atatarinowii Schott and consisted of the 28th,30th and 36th peaks which corresponded to γ asarone,β asarone and α asarone,respectively.This study provided a new approach for the comparison and quality assessment of Atatarinowii Schott from different growing areas.关键词：Acorus tatarinowii Schott;gas chromatography-mass spectrometry;volatile constituents;dividing sections
- 2204
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- 1116
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- 1
发布时间： - 摘要：2,3-Dihydro-9,10-dihydroxy-1,4-anthraquinone（R）was synthesized and characterized by 1H NMR，IR，MS and UV-Vis spectrometry.Based on the facts that R can emit intense and stable solid substrate-room temperature phosphorescence(SS-RTP) on solid substrate，and α，α dipyridine can activate Hg2+ to catalyze the reaction of H2O2 oxidizing R to form non phosphorescence compound, a new solid substrat-room temperature phosphorescence quenching method was established for the determination of trace mercury.Under the optimum condition，the relationship between the ΔIp of the emitting intensity and 1.60-160 fg/spot Hg2+（corresponding concentration:0.004 0-0.40 μg/L，sample volume:0.4 μL/spot） conformed to Beer law.The regression equation was ΔIp=11.56＋0.549 2 m（fg/spot） （r=0.999 1）.The limit detection was 0.26 fg/spot（corresponding Hg2+ concentration:6.5× 10-10 g/L）.The spiked recoveries were in the range of 97%-103% with RSDs of 2.3%-4.1%.The RSDs（n=11） of 0.004 0 μg/L and 0.40 μg/L Hg2+ were 2.6% and 4.1%，respectively.The method showed good repeatability，sensitivity and high precision.It was applied in the determination of trace mercury （Ⅱ） in real samples with satisfactory results.关键词：anthraquinone;phosphorescence quenching method;mercury;determination
- 1973
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- 928
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- 0
发布时间： - 摘要：A methodology regarding preparation and certification of certified reference material (CRM) of theophylline was presented．The CRM was prepared by repeated recrystallization and drying at 80 ℃ in vacuum condition for 5 h.According to analysis procedure of homogeneity,11 bottles of sample were randomly taken from 500 bottles,in which one bottle was measured for ten times,the other ten bottles were respectively measured for one time,and the results were validated by F test and T test statistical methods.The stability inspection was carried on the short term(one month) and the long term(12 months),and the results indicated that the period for theophylline of storage was 12 months at 20 ℃.The purity of theophylline were determined by two methods eg.mass balance method and differential scanning calorimetry(DSC) method,based on different principles．The qualitative and quantitative analysis of impurities were respectively performed by liquid chromatography ion trap time of flight mass spectrometry(LC-IT TOF) and high performance liquid chromatography with diode array detector(DAD).The content of water in theophylline was measured by Karl-Fischer titrator with drying oven using methanol as solvent.Volatile material in theophylline was determined by temperature gravity analysis(TGA).The determination of losses on drying ash was carried out by the routine method.The uncertainty of mass balance method and DSC methods were respectively evaluated.The result showed that the certified result was 99.80% and expanded uncertainty was 0.14%(k=2).关键词：theophylline;certified reference material;mass balance method;LC-IT TOF;differential scanning calorimetry(DSC) method
- 2030
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- 1039
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- 7
发布时间： - 摘要：A modified electrode based on chitosan-copper complex（CTS-Cu） was developed for the quick determination of hydrogen peroxide（H2O2）.The CTS-Cu complex was prepared via the coordination interaction of chitosan and copper（Ⅱ） salt and was used to modify glassy carbon electrode（GCE）.The electrocatalytic performance of the resulting CTS-Cu modified electrode（CTS-Cu/GCE） to H2O2 was investigated by cyclic voltammetry（CV） and chronoamperometry（CA）.The mechanism of the catalytic reaction was further discussed.The experimental conditions were optimized and listed as follows：0.1 mol/L phosphate buffer solution（PBS，pH 7.0） was used as the reaction medium，the concentration of copper（Ⅱ） in the CTS-Cu modified solution was 6 mmol/L，and the applied potential was-0.20 V.Under the optimum conditions，the peak current of the modified electrode was proportional to the concentration of H2O2 in the range of 3.9×10-5-1.4×10-3 mol/L with a detection limit of 3.6×10-6 mol/L.The relative standard deviation（RSD，n=5） was 3.4%.The results indicated that the preparation method was simple，and the employment of the modified electrode was also convenient.Moreover，the modified electrode has the advantages of high sensitivity，excellent electrocatalytic performance to H2O2，and good anti interference ability in the determination of H2O2 with satisfactory result.关键词：copper;chitosan;H2O2;modified electrode;electrocatalysis
- 2017
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- 1033
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- 3
发布时间： - 摘要：A method for the determination of clenbuterol，chloramphenicol and diethylstilbestrol in bovine milk was developed by isotope dilution ultra high performance liquid chromatography-tandem mass spectrometry.Samples were directly purified through HLB cartridge with 5 mL water and 5 mL hexane as washing solution.The analytes were eluted with 15 mL ethyl acetate.Then the eluate was evaporated to dryness at 40 ℃ under nitrogen and redissolved with 5 mmol?L-1 of ammonium acetate solution-acetonitrile（90∶10，by volume）.The analytes were analyzed by LC-MS/MS on an Acquity UPLC BEH C18 column using acetonitrile -5 mmol?L-1 ammonium acetate as mobile phase by gradient elution.The mass spectrometer was operated under multiple reaction monitoring（MRM） mode.The samples were quantified by the internal standards labeled with stable isotopes.The calibration curves of clenbuterol，chloramphenicol and diethylstilbestrol were linear in the ranges of 0.2-20，1.2-100,2.0-200 μg?L-1，respectively，with correlation coefficients more than 0.998 5.The limits of detection of clenbuterol，chloramphenicol and diethylstilbestrol were 0.009，0.007,004 ng?g-1，respectively.The recoveries of three drugs in bovine milk sample at the fortified levels of 0.05-0.10（clenbuterol），0.30-0.60（chloramphenicol），0.50-1.0 ng?g-1（diethylstilbestrol） were in the range of 94%-107% with RSDs less than 10%.The method was suitable for the determination of clenbuterol，chloramphenicol and diethylstibestrol residues in bovine milk.关键词：clenbuterol;chloramphenicol;diethylstilbestrol;liquid chromatography-tandem mass spectrometry;isotope dilution;bovine milk;residue
- 12182
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- 4422
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- 4
发布时间： - 摘要：A new high performance liquid chromatographic（HPLC） method with ultraviolet detection was firstly developed for the determination of 2 （3 tert butyl 2 hydroxy 5 methylphenyl） 5 chloro 2h benzotriazole（UV 326） and 2 （2 hydroxy 3,5 di tert butylphenyl） 5 chlorobenzotriazole（UV 327） in composite laminated food packaging bags.The samples were extracted by ultrasound assisted extraction method.Then，the extracts were further concentrated by rotary evaporation technology and cleaned up with solid phase extraction column.The eluent was evaporated to near dryness under a stream of nitrogen and redissolved with methanol.The separation of target compounds was performed with Agilent ZORBZX SB C18 column（250 mm×4.6 mm,5 μm） using methanol as elution reagent at a flow rate of 1.0 mL/min at 30 ℃.The quantitative analysis of target compounds was performed by the external standard method at a detection wavelength of 310 nm.The result indicated that the calibration curves were linear in the range of 0.2-10 mg/kg for UV 326 and UV 327 with both limits of quantitation of 0.2 mg/kg.The average recoveries of UV 326 and UV 327 were in the range of 75%-90% and 80%-85%,respectively，with RSDs of 3.6%-6.7% and 3.4%-4.2%,respectively.The method could be applied in the determination of UV 326 and UV 327 in composite laminated food packaging bags.关键词：UV 326;UV 327;ultraviolet stabilizer;composite laminated food packaging bags;high performance liquid chromatography（HPLC）
- 2162
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- 977
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- 7
发布时间： - 摘要：A novel method was developed for the determination of chlorocholine chloride（CCC） and mepiquat chloride（MQ） residues in soil and irrigation water based on SPE/HPLC-MS/MS technique.To investigate their enrichment efficiencies to CCC and MQ，4 kinds of SPE columns were used to pretreat samples，including silica gel column,C18 column and weak cation exchange(WCX) column.The results showed that the highest efficiency was obtained by using WCX column with 5 mL of 10 mmol/L ammonium acetate(containing 0.1% formic acid) -methanol(1∶9) as elution.The separations of analytes were performed on a HILIC column（1.7 μm，2.1 mm×50 mm） by a gradient elution using acetonitrile-10 mmol/L ammonium acetate(containing 0.1% formic acid) as moblile phase.The mean recoveries of CCC and MQ were in the range of 73%-91% and 76%-90%,respectively,with RSDs of 8.2%-12.4% and 42%-13.2%,respectively.The calibration curves of CCC and MQ were linear in the range of 1.0-50.0 μg/L with correlation coefficients more than 0.999.The detection limits of CCC and MQ both were 0.125 μg/kg for soil samples and 0.02 μg/L for water samples.The method was applied in the real soil and water samples from Karashahr area，Xinjiang，and no CCC and CQ were detected.The method was reliable，robust and sensitive for the determination of CCC and CQ in soil and water samples.关键词：chlorocholine chloride;mepiquat chloride;solid phase extraction;UPLC-MS/MS;pesticide residue
- 2203
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- 1615
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- 2
发布时间： - 摘要：Danshensu is one of the water soluble salvianolic acids which is extracted from Salvia. In this article, the interaction between Danshensu and bovine serum albumin (BSA） in aqueous solution was investigated by ultraviolet spectra and synchronous fluorescence spectra. Ultraviolet spectra showed that Danshensu could interact with BSA to form a stable complex. Fluorescence spectra showed that,with the increased concentration of Danshensu, fluorescence intensity (Δλ=15 nm) increased significantly and the maximum emission wavelength was stable at 285 nm,it is right for calculation the binding parameters of Danshensu-BSA. As Δλ=60 nm, the emission spectrum of Danshensu-BSA system showed a blue shift but the fluorescence intensity increased unobviously.The binding parameters of Danshensu-BSA were calculated based on the data of synchronous fluorescence spectra for the first time. The binding constants at 298, 308 and 318 K were 1.43×106, 1.25×106,5.00×105 L/mol, respectively. The thermodynamic parameters (ΔH=-10.28 kJ/mol, ΔS>0） implied that electrostatic force should be the predominant intermolecular force stabilizing the Danshensu-BSA complex．关键词：synchronous fluorescence spectrum;Danshensu;BSA;fluorescence enhancement
- 2175
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- 1076
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- 7
发布时间： - 摘要：A highly selective and sensitive analytical method was developed for simultaneous determination of three classes of commonly used antibiotics，including five sulfonamides，three tetracyclines and one macrolide in the activated sludge of municipal sewage treatment plants（STPs） by ultrasonic extraction，solid phase extraction and high performance liquid chromatography-mass spectrometry （LC-MS）. The activated sludge sample was ultrasonically extracted with a mixture of methanol and Na2EDTA／McIlvaine buffer（1∶1），then concentrated and purified with an HLB cartridge. The separation of targeted compound was performed with a Waters Symmetry C18 column using 0.2% formic acid（A）-acetonitrile（B） as mobile phase. The qualification and quantification of the selected antibiotics were carried out by MS with an electrospray ionization（ESI） under the positive ion mode. The method showed good linearity（r2 > 0.99） for the antibiotics concentration in the range of 0.001-1 mg／L. The recoveries at three spiked levels were in the range of 80%-108% for sulfonamides（SAs），91%-112% for tetracyclines（TCs） and 50%-59% for tiamulin（TIA）. The inter day and intra day relative standard deviations were no more than 7.4% and 13.7%，respectively. The limits of detection（LOD） were between 1 μg/kg and 16 μg/kg. The developed method was applied in the detection of the activated sludge samples collected from two STPs located in Beijing and five target antibiotics were detected with concentrations of 124.9-523.3 μg/kg for sulfanomindes and 166.5-2 296.4 μg/kg for tetracyclines，respectively.关键词：antibiotics;high performance liquid chromatography- mass spectrometry;municipal sewage treatment plant;activated sludge
- 2540
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- 1207
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- 17
发布时间： - 摘要：A new method of microfluidic chip with contactless conductivity detection was established for the determination of amantadine hydrochloride in amantadine hydrochloride tablets．The electrophoretic parameters，such as the variety and concentration of buffer solution and additive，separation voltage and injection time etc，were investigated．Under the optimal conditions，using 1 mmol/L HAc+2 mmol/L NaAc（pH 4.5）+0.1 mmol/L SDS as buffer solution system，amantadine hydrochloride was separated and detected in 1 min at the separation voltage of 2.00 kV and 10 s injection time．The linear dependence of the concentration of amantadine hydrochloride ranged from 10 mg/L to 120 mg/L （r=0.999 0），with a detection limit（S/N=3） of 0.6 mg/L.The spiked recoveries ranged from 97% to 98% with RSDs of 0.8%-2.2%.The method was simple，rapid and well reproducible，and could be used for the rapid detection and the quality control of the product.关键词：microfluidic chip;contactless conductivity detection;amantadine hydrochloride;determination
- 1858
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- 992
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- 9
发布时间： - 摘要：The maximum absorption wavelengths of rutin and quercetin are very close and their absorption spectra are seriously overlapping,so its very difficult to determine individually rutin or quercetin by spectrophotometry without prior separation.In this paper，a partial least squares-spectrophotometry was developed for the simultaneous determination of rutin and quercetin.The absorption spectra of rutin and quercetin mixed standard were studied in the range of 200-500 nm and the absorbance values were recorded every 2 nm.A partial least squares（PLS） model was built for the simultaneous determination of the contents of rutin and quercetin in the flos sophorae and synthetic samples.The results indicated that the recoveries of rutin and quercetin in the flos sophorae were in the range of 95.6%-99.8% and 99.8%-99.9%,respectively,and the recoveries of rutin and quercetin in the synthetic samples were in the range of 97.6%-102.1% and 100.2%-102.2%,respectively.The method showed high accuracy and satisfied precision,and could reduce the effect of noise effectively.关键词：partial least square spectrophotometry;rutin;quercetin;simultaneous determination
- 1987
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- 996
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- 11
发布时间： - 摘要：A double internal standard quantitative method of capillary GC-MS was established for the determination of nicotine using campor and m cresol as the double internal substances.The result indicated that，under the same chromatographic conditions，the linear correlation coefficient of nicotine obtained from the double internal standard quantification curves was better than that obtained by the single internal standard method.This may be due to one more volatile substance as internal standard resulting in the rapid uniform distribution of samples partial pressure in the injection chamber.The effects of reducing the concentration of one standard and the location of the analyte peaks appeared on the correlation of the quantitative linear curve were also discussed.Therefore，it could be concluded that the double internal standard method coupled with quantitative capillary analysis can effectively eliminate the discrimination effect as injectting sample，and improve the accuracy of quantitative analysis.关键词：GC-MS;capillary column;discrimination effect;double internal standard
- 3680
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- 1172
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发布时间： - 摘要：β2 agonists have been banned as a feed additive in most countries.But the misuses occurred sometimes.It is important to emphasize the detection of β2 agonists in food samples.In this paper,the pretreatment methods for β2 agonist analysis,including solvent extraction,solid phase extraction,solid phase microextraction，etc.are summarized.The analytical methods of β2 agonist，such as chromatography analysis,electrochemical detection,enzyme linked immunosorbent assay and chemiluminescence method,are reviewed.关键词：β2 agonist;sample pretreatment;analysis
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