最新刊期
卷 32 ， 期 8 ， 2013
- 摘要：A QuEChERS sample pretreatment coupled with ultra high performance liquid chromatography-LTQ Orbitrap mass spectrometric（UHPLC-LTQ Orbitrap MS） method was developed for the simultaneous determination of 5 glucocorticoids residues,including dexamethasone,prednisone,hydrocortisone,methylprednisolone and tiramcinolone,in chicken muscle tissues.The QuEChERS pretreatment procedure was optimized.The chicken muscle samples were extracted with ethyl acetate and cleaned by PSA dispersive solid phase extraction.The separation of target compounds was performed on a Waters AQUITY UPLC HSS T3（2.1 mm×150 mm,1.8 μm） column by gradient elution using acetonitrile-water（containing 0.1% formic acid） as mobile phase at a flow rate of 0.25 mL/min.Identification of the glucocorticoids was based on the retention time and the exact mass of ［M+H］+ ions,and quantification of the glucocorticoids was based on the peak area of ［M+H］+ ions.The linear ranges of five compounds were in the range of 1-100 μg/L,with correlation coefficients more than 0.99.The average recoveries of 5 glucocorticoids at spiked levels of 5,10,20 μg/kg ranged from 87.5%to 119.7%,with relative standard deviations（RSDs） of 2.0%-11.0%.The limits of detection（LODs）of the method ranged from 0.49 μg/kg to 0.78 μg/kg,and the limits of quantitation（LOQs） ranged from 1.62 μg/kg to 2.57 μg/kg.The method was reliable and efficient,and could be applied in the determination of 5 glucocorticoids in chicken muscle samples.关键词：dexamethasone;glucocorticoids;chicken muscle;QuEChERS pretreatment;UHPLC-LTQ Orbitrap MS
- 1888
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- 1040
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- 14
发布时间： - 摘要：A method was developed for the simultaneous determination of 15 phthalic acid esters at trace level in aquatic products by solid phase extraction（SPE） purification coupled with gas chromatography-mass spectrometry（GC-MS）.The PAEs were extracted with dichloromethane-hexane（1∶1） by ultrasonic-assisted technique,then purified with SPE glass column packed with 3.0 g neutral alumina caped with approximately 2 cm anhydrous sodium sulfate on the top. The target analytes were eluted with hexane,dichloromethane-hexane（1∶9） mixture,ethyl acetate-hexane（1∶4）mixture,and ethyl acetate,sequentially.The eluent was evaporated to near dryness,and redissolved in 1 mL hexane,and analyzed by GC-MS under the selected ion monitoring mode.Under optimized conditions,the linear ranges of 15 phthalic acid esters were in the range of 0.05-1.0 mg/L with correlation coefficients（r） not less than 0.999 1.The average recoveries of 15 phthalic acid esters in different kinds of fishery products samples at spiked levels of 2,50,200 μg/kg were in the range of 81%-123%,with relative standard deviations（RSDs,n=3） less than 15%.The limits of detection（LOD,S/N=3） ranged from 0.04 μg/kg to 1.18 μg/kg,and the limits of quantitation（LOQ,S/N=10） ranged from 0.20 μg/kg to 4.00 μg/kg.The proposed method is suitable for the simultaneous determination of 15 phthalic acid esters in fishery products with easy operation,high accuracy and precision.关键词：phthalic acid esters（PAEs）;aquatic products;gas chromatography-mass spectrometry（ GC-MS）
- 2032
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- 1278
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- 14
发布时间： - 摘要：A high-performance liquid chromatography-tandem mass spectrometric（HPLC-MS/MS） method was developed to analyze abamectin in sediment.The sample was extracted with a mixture of hexane and acetone by ultrasound-assisted microwave extraction,and purified with solid phase extraction column packed with primary/secondary amine and graphite carbon black.The analytes were separated on a Thermo-C18 column（50 mm×2.1 mm,1.9 μm） using a mixture of acetonitrile∶acetic acid-ammonium acetate∶water（75∶10∶15） as mobile phase.The analysis of the target compounds was performed under atmospheric pressure chemical ionization mode with multiple reaction monitoring.The quantification of abamectin was based on internal standard calibration（emamectin benzoate as the internal standard）,and the calibration standards were prepared using matrix matched solution for compensation of matrix effect.The calibration curve of abamectin was linear in the range of 1.6-400 μg/L with correlation coefficient（r2） of 0.999 3.The relative standard deviations ranged from 2.2% to 16.2%,and the limit of detection was 0.18 ng/g by dry weight.The established method was used to analyze sediment samples collected from an urban stream in Guangzhou,and the results were compared with those obtained by the HPLC/fluorescence detection after derivatization.Similar results were achieved by both methods,but the HPLC-MS/MS method showed greater sensitivity and simplicity,and was suitable for the detection of sediment-associated abamectin at low concentrations.关键词：abamectin;HPLC-MS/MS;sediment;pesticide residue
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发布时间： - 摘要：Structure analysis of dialkyl propylphosphonates requires the specific identity of isomeric propyl groups bonded to phosphorus.To this end,homologous series of isomeric dialkyl iso-and n-propylphosphonates were analysed by gas chromatography-quadrupole tandem mass spectrometry.For identification of the isomer,characteristic ion m/z 125 in electron impact mass spectrometry（EI-MS） and quasi-molecular ions in chemical ionization mass spectrometry（CI-MS） were studied by tandem mass spectrometry（MS/MS） in product scan mode.The parameters including collision energy and collision gas pressure were optimized.The experiments showed that precursor ions m/z 125 of dialkyl n-propylphosphonate screened mainly product ion m/z 107 under condition of 20 V of collision energy and 1.0 mTorr of collision gas pressure by EI-MS/MS,while precursor ions m/z 125 of dialkyl isopropylphosphonate screened mainly product ions m/z 65 and m/z 83.In the same condition,quasi-molecular ions of dialkyl n-propylphosphonate,which were precursor ions,screened mainly product ions m/z 125 and 107 and quasi-molecular ions of dialkyl isopropylphosphonate screened mainly product ions m/z 125,107 and 83.For most chemicals,the product ion m/z 125 is base peak.Based on EI and CI tandem mass spectrometry,the isomeric dialkyl propylphosphonates could be rapidly identificated.关键词：dialkyl n-propylphosphonate;dialkyl isopropylphosphonate;isomer;MS/MS
- 1837
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- 969
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- 0
发布时间： - 摘要：A liquid chromatography-tandem mass spectrometric（LC-MS/MS） method with solid phase extraction was developed for the determination of 7 plant growth regulators（PGRs），including 2,4-dichlorophenoxyacetic acid，gibberellic acid，indole-3-butyric acid，α-naphthaleneacetic acid，4-fluorophenoxyacetic acid，4-chlorophenoxyacetic acid and indole-3-acetic acid，in orange.The samples were extracted with acetonitrile（contain 2% formic acid），and cleaned up on a Poly-Sery MAX.The extract was eluted with 4% formic acid in methanol，then evaporated with a stream of nitrogen to near dryness，and redissoved with acetonitrile-water（1∶9）. The targeted compounds were separated on a Phenomenex Gemini-NX 5u C18 110A（2.0 mm i.d.×150 mm，5.0 μm），and determined by LC-MS/MS under MRM mode with the matrix-matched external standard method.The results indicated that the calibration curves were linear in the certain concentration range with correlation coefficients greater than 0.99.The limits of detection（LODs，S/N>3） were in the range of 0.3-3.5 μg/kg and the limits of quantitation（LOQs，S/N>10） were 5.4-57.7 μg/kg.The recoveries of 7 PGRs in orange at three spiked levels ranged from 79.6% to 110.3% with relative standard deviations（RSDs） of 3.1%-10.0%.The established method was simple and sensitive，and could meet the requirements for simultanous analysis of PGRs in amphisarcas.关键词：solid phase extraction（SPE）;high performance liquid chromatography-tandem mass spectrometry（HPLC-MS/MS）;plant growth regulator（PGR）;orange;residue
- 2055
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- 1596
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- 6
发布时间： - 摘要：A high performance liquid chromatography-inductively coupled plasma mass spectrometric（HPLC-ICP-MS） method was developed for the determination of 4 arsenic species,including arsenite（As（Ⅲ））,arsenate（As（Ⅴ））,monomethylarsonic acid（MMA） and dimethylarsinic acid（DMA）,in tobacco.The extract efficiencies of different extract solvents,extract solvent volume and extract time were investigated.The chromatographic conditions were also optimized.The milled tobacco samples were mechanically extracted with 15 mL mixture of methanol-water（1∶1） by ultrasonic method for 20 min at 30 ℃.The target species in tobacco were analyzed on an anion exchange cartridge（PRP-X100） using diammonium phosphate（pH 6.0）as mobile phase.Good linearities of 4 arsenic species were observed in the range of 0.1-25 μg/L with correlation coefficients not less than 0.997.The RSDs of intra- and inter-day were both not more than 4.2%.The limits of detection（LODs） were between 0.1 μg/L and 0.2 μg/L, and the limits of quantitation（LOQs） were between 0.2 μg/L and 0.5 μg/L.The spiked recoveries for all arsenic species were in the range of 83%-115%.Good stabilities were found with RSDs not more than 5.7%.The method was applied in the detection of 4 arsenic species in eight kinds of tobaccos,in which all arsenic species were detected and their contents from high to low were:As（Ⅴ）,MMA,As（Ⅲ） and DMA.The method was proved to be accurate,sensitive and convenient for analysis of arsenic species in tobacco sample.关键词：high performance liquid chromatography-inductively coupled plasma-mass spectrometry（HPLC-ICP-MS）;arsenic species;tobacco
- 1888
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- 1066
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- 8
发布时间： - 摘要：A novel fluorescence enhancing probe for Hg2+,3′,6′-bis(diethylamino)-2-((2-hydroxy-4-methoxybenzylidene)amino)spiro［isoindoline-1,9′-xanthene］-3-thione (RBS),was designed and synthesized.Its structure was characterized with IR,elemental analysis and 1H NMR spectra.The fluorescence intensity of probe solution is very weak,but after combination with Hg2+,its fluorescence intensity increased obviously.Thus,a new method for the determination of Hg2+ was established.It exhibits a dynamic response concentration range for Hg2+ from 5.00×10-9 mol/L to 1.10×10-6 mol/L with a detection limit of 2.82×10-9 mol/L.The method showed advantages of simplicity,high sensitivity,excellent selectivity and wide linear range,and was applied in the determination of Hg2+ in real sample with satisfactory result.关键词：fluorescent spectrometry;fluorescent probe;mercury ion (Ⅱ);rhodamine B derivatives
- 2198
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- 1018
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- 2
发布时间： - 摘要：A new method for the determination of norepinephrine（NE）was established with the disposable screen printed electrode（SPE）modified with the multiwalled carbon nanotubes and ZnO nanocomposites（MWNTs-ZnO）using screen printing technology.A sensitive response to NE was obtained on the MWNTs-ZnO SPE at the potentail of 0.28 V.Square wave voltammetric（SWV）response of NE showed that the oxidation peak current of NE at MWNTs-ZnO SPE was linear with its concentration in the range of 0.75-50 μmol/L.The linear regression range was 0.75-50 μmol/L（r2=0.999 3），and the detection limit（S/N=3）was 0.3 μmol/L.This method was simple，rapid and sensitive，and could be used to monitor NE in a large batch of clinical samples.关键词：MWNTs-ZnO nanocomposites;screen printed electrode;norepinephrine;detection
- 1878
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- 1017
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- 2
发布时间： - 摘要：A novel method for the determination of aflatoxin B1,M1 in foods was developed using homemade mixed solid phase extraction column coupled with high performance liquid chromatography.The sample was extracted with 60%acetonitrile solution,and cleaned up on a homemade mixed solid phase extraction column.The separation was performed on a Shim-pack VP-ODS C18 column with acetonitrile-water（20∶80） as mobile phase within 13 min.The contents of two aflatoxins were detected with fluorescence detector,and quantified by the external standard method.The effects of column type,column capacity,sample amount,extraction solution and flow rate on the determination of aflatoxin residue were investigated.Under the optimized conditions,there were good linearities between peak areas and aflatoxins concentrations in the range of 0.40-100 μg/L with correlation coefficients of 0.999 4-0.999 7.The limits of detection（S/N=3） of aflatoxin B1,M1 were both 0.050 μg/kgThe recoveries of aflatoxins in different samples at three spiked levels of 0.40,1.0,100 μg/L were in the range of 53%-112% with relative standard deviations（RSDs） of 2.7%-7.1%.The proposed method showed the advantages of sensitivity,simplicity and fastness,and was successfully applied in the determination of low aflatoxins residues in peanut,pistachio and milk samples.关键词：homemade mixed solid phase extraction column;high performance liquid chromatography（ HPLC ）;foods;aflatoxins（AFT）
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- 5
发布时间： - 摘要：An effective liquid chromatography-tandem mass spectrometric（HPLC-MS/MS） method was developed for the determination of ethyl carbamate in cigarette mainstream smoke.The ethyl carbamate in cigarette mainstream smoke was trapped with Cambridge filter,and then extracted with an oscillation using ethanol as extraction solvent.Influences of elution solvent type,solvent consumption and different polarity solid-phase extractions on purification efficiency of the target analyte were discussed.Under the optimal conditions,the calibration curve of the method was in the range of 6-720 μg/L with correlation coefficient（r2） of 0.999 9.The relative standard deviations（RSDs） of intra-day and inter-day were less than 6% and 5%,respectively.The spiked average recoveries ranged from 93.7% to 99.8%,and the limit of quantitation（LOQ） was 0.26 ng/cig.With the advantages of accurancy,sensitivity,good reproducibility and low solvent consumption,the method was suitable for the determination of ethyl carbamate in cigarette mainstream smoke.关键词：liquid chromatography tandem mass spectrometry（HPLC-MS/MS）;mainstream smoke;ethyl carbamate
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- 1155
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- 3
发布时间： - 摘要：A novel method for simultaneous determintation of intracellular reactive oxygen species and apoptosis signal was developed by microchip capillary electrophoresis with laser induced fluorescence detection.Alexa Fluor- 488 annexin V was used to label phosphatidyl serine in outer surface of the apoptosis cells,and dihydrorhodamine 123（DHR123） was used to convert ROS to the fluorescent rhodamine 123（Rh123） intracellularly. The cells were diluted with PBS to a final density of 1.2×106 cells/mL,and then crushed by a repetitive freeze thaw method. The supernatant was separated in 1 min using 20 mmol/L borate buffer（pH 9.2） as buffer medium, with a separation voltage of 1.2 kV and an injection time of 60 s. Under the optimized experimental conditions,the calibration of Rh123 was linear in the range of 0.5-3 μmol/L with a correlation coefficient (r) of 0.998.The limit of detection（S/N=3） was 0.058 μmol/L.The established method was applied in the HepG2 cancer cell,and ROS in cells was quantified as 0.16 μmol/L before and 1.77 μmol /L after apoptosis.关键词：microfluidic chip;reactive oxygen species(ROS);apoptosis
- 2612
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- 998
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- 3
发布时间： - 摘要：A high performance liquid chromatography-mass spectrometric(HPLC-MS) method was established for the simultaneous determination of five trace preservatives in beer.The sample was heated in water bath,cleaned up with a C18 solid phase extraction column,and then analyzed under parent ion monitoring mode.Matrix-matched calibration curve was used to determine the trace contents by external standard method.The method showed good linearities in the range of 0.1-10.0 mg/L for five targets,with correlation coefficients more than 0.99.The recoveries at three spiked concentration levels ranged from 62.2% to 125.0%,with RSDs of 0.14%-3.4%.The limits of detection（LODs） for benzoic acid and sorbic acid were 0.020 mg/L and 0.015 mg/L,and the limits of quantitation（LOQs） were 0.060 mg/L and 0.050 mg/L,respectively.While the LODs of three parabens were all 0.010 mg/L and the LOQs were all 0.045 mg/L.With good purifying effect,sensitivity,recovery and repeatability,the developed method is suitable for the determination of preservatives in beer for sales.关键词：beer;preservatives;solid phase extraction;high performance liquid chromatography-mass spectrometry（HPLC-MS）
- 1968
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- 1252
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- 5
发布时间： - 摘要：A method was developed for the determination of furazolidone（FZD），furaltadone（FTD），furacilin（NFZ）and nitrofurantoin（NFT） residues in feedstuff by isotope dillution high performance liquid chromatography-tandem mass spectrometry.After homogenization，samples were extracted with acetonitrile.After centrifugation，the extract was evaporated to dryness with nitrogen at 40℃，and redissolved with acetonitrile-0.05%ammonium acetate solution.The solution was defatted with hexane and cleaned up with neutral alumina solid phase extraction cartridge.The targeted compounds were seperated on a Sunfire C18（150 mm×2.1 mm，5 μm） column by using methanol-0.05% ammonium acetate as mobile phase，and detected with electrospray ionization（ESI） under positive and negative switching scan mode， in which negative scan mode was used for NFZ and NFT,respectively，and positive scan mode was used for FZD and FTD.The detection limits were 2.0 μg/kg for FZD and NFT and 3.0 μg/kg for FTD and NFZ,respectively.The quantitation limits were 5.0 μg/L for FZD and NFT，and 10.0 μg/kg for FTD and NFZ,respectively.The linear ranges of the target compounds ranged from 5.0 μg/L to 100.0 μg/L with correlation coefficients greater than 0.99.The recoveries of four compounds in spiked feed for tilapia were in the range of 78%-107% with relative standard deviations（RSDs） less than 12%.The method is rapid and accurate，and is suitable for the detection of four nitrofuran drugs in feedstuff.关键词：liquid chromatography-tandem mass spectrometry（LC-MS/MS）;positive and negative switching scan mode;nitrofuran antibiotics;feedstuff
- 2368
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- 1214
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发布时间： - 摘要：α-Cyano-3-methoxy-4-hydroxycinnamic acid（CFA）was applied in analysis of the synthesized polymer A and B by matrix-assisted laser desorption/ionization time of flight mass spectrometry（MALDI-TOF-MS）.The results showed that CFA can exhibit an excellent matrix function,compared with the common matrices（e.g.DHB,HCCA,SA and DIT） in terms of resolution and signal-to-noise of the obtained mass spectra.The information of the relative molecular mass,molecular weight distribution and constitutional repeating unit of polymer A and B were obtained,which will be instructive to the optimization of polymer reaction conditions and the speculation of reaction mechanism.关键词：α-cyano-3-methoxy-4-hydroxycinnamic acid;matrix;laser desorption/ ionization mass spectrometry;polymer
- 1956
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- 1015
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- 2
发布时间： - 摘要：A novel method for the determination of trace rhodium by laser thermal lens spectrometry（LTLS） based on the sensitive color reaction between rhodium（Ⅲ） and 2-（5-bromo-2-pyridylazo）-5-dimethylaminoaniline（5-Br-PADMA）was established.The experiment results showed that in a media of pH 3.6-6.0 HAc-NaAc buffer solution,rhodium（Ⅲ） can react with 5-Br-PADMA to form a violet-red complex.The complex can be changed into another green-blue proton species possessing a high abosorption characteristics in 1.2 mol/L HClO4.The optimal concentrations of HClO4,HCl,H2SO4 or H3PO4 were found to be 0.6-3.6 mol?L-1 for HClO4,0.6-3.0 mol/L for HCl,1.2-4.0 mol/L for H2SO4 and 1.8-4.5 mol/L for H3PO4,respectively.The maximum absorption wavelength was 612 nm which matched well with the output wavelength（632.8 nm） of He-Ne laser.The analytical curve was linear in the concentration range of 5-140 μg/L for rhodium,and the detection limit was 1.1 μg/L.The method,having high sensitivity and good selectivity,was applied in the determination of trace rhodium in the rhodium-carbon catalyst with satisfactory results.关键词：2-（5-bromo-2-pyridylazo）-5-dimethylaminoaniline;laser thermal lens spectrometry;rhodium
- 1783
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- 952
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- 3
发布时间： - 摘要：Degradation mechanism of decabromodiphenyl ethers was studied by gas chromatography-mass spectrometry（GC-MS）.Effects of storage time,storage temperature,light and concentration of decabromodiphenyl ethers on the degradation proccess of decabromodiphenyl ethers were evaluated,and the degradation products were detected.The results showed that the decabromodiphenyl ethers were degraded as the storage time extended at ambient temperature.The degradation rate was rapid, and 848% decabromodiphenyl ethers were degraded in 10 h when they were exposed to ultraviolet rays.The major degradation mechanism of decabromodiphenyl ethers were debromination,and the degradation products were the following potentially toxic compounds:nonabromodiphenyl ethers,octabromodiphenyl ethers,heptabromodiphenyl ethers,hexabromodiphenyl ethers and pentabromodiphenyl ethers.This study can provide a scientific guidance for determination of decabromodiphenyl ethers in electrical and electronic equipments.关键词：gas chromatography-mass spectrometry（GC-MS）;decabromodiphenyl ethers;degradation mechanism
- 2146
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- 1155
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- 1
发布时间： - 摘要：A new efficient electrochemiluminescence（ECL） immunoassay strategy was developed for the determination of abrin based on the large specific surface area and excellent biocompatibility of GoldMag particles.The assay consisted of a double antibody sandwich format in which polyclonal antibody（PcAb） of abrin was immobilized on GoldMag particles as capture probe,and Ru（bpy）2+3-labeled monoclonal antiboday（McAb） for ECL probe.First,immobilized PcAb,abrin and Ru（bpy）2+3-labeled McAb formed sandwich immunocomplex via the specific immune response.Then abrin was determined by electrochemiluminescence（ECL） reaction.A logarithmic linear relationship（r=0.998 4） between ECL intensity and concentration of abrin in the range of 0.2-1 500 μg/L was obtained,and the detection limit was 0.2 μg/L.Compared with the biotin-avidin immobilization method,this new approach possesses more considerable sensitivity,wider linear range,more simplified steps and holds a great promise in the sensitive detection of target proteins in various fields such as clinical diagnosis,environmental monitoring and biodefense.关键词：GoldMag particles;electrochemiluminescence;immunoassay detection;abrin
- 2688
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- 1007
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- 4
发布时间： - 摘要：A reversed-phase high performance liquid chromatographic method was developed for the determination of amino acids in eptifibatide injection using phenyl isothiocyanate as pro-column derivatization reagent.The chromatographic parameter was optimized,and the analysis of amino acids was performed on a Agilent XDB-C18 column（5 μm,150 mm×4.6 mm）,using 0.1 mol/L sodium acetate（adjusting the pH to 6.0 with acetic acid） and acetonitrile（90∶10,A）-acetonitrile（B） as mobile phase by gradient elution at a flow rate of 1.0 mL/min and an injection volume of 5 μL.The detection wavelength was set at 254 nm,and the column temperature was set at 30 ℃.Under the optimal conditions,the amino acids were effectively separated. good linearities were obtained in the range of 1.23-3.68 mmol/L for all amino acids,with correlation coefficients(r) of 0.999 1-0.999 6.The method showed high selectivity,good repeatability,accuracy and stability,and could be applied in the accurate quantification of amino acids in eptifibatide injection.关键词：phenyl isothiocyanate;derivatization;amino acid;RP-HPLC
- 1944
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- 1086
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- 3
发布时间： - 摘要：A gas chromatography- mass spectrometric（GC-MS） method was established to simultaneously detect 5 kinds of fruit preservatives including p-methyl hydroxybenzoate，p-ethyl hydroxybenzoate，ethyl naphthol，4-phenyl phenol and diphenyl ether.The samples were extracted with ether，concentrated by nitrogen blowing，and purified with activated carbon column.The analysis of target compounds was performed by GC-MS under the selected ion mode（SIM）,and quantified by the external standard method.Under the optimized conditions，the calibration curves of the 5 preservatives were linear in the range of 0.2-4.0 mg/L with correlation coefficients（r2） more than 0.991.The spiked recoveries ranged from 80.4% to 104.5% with relative standard deviations （RSDs） of 1.2%- 6.4%.The limit of detection of diphenyl ether was 0.05 mg/kg，and those of the other analytes were all 0.1 mg/kg.The method was simple，rapid and cheap，and the impurities like pigments in fruit samples could be diminished with activated carbon column.Therefore，the method was suitable for the determination of the 5 preservatives residues in fresh fruits with high sensitivity and selectivity.关键词：gas chromatography-mass spectrometry（GC-MS）;fresh fruit;preservatives;residue amount
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- 1002
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- 1
发布时间： - 摘要：A gas chromatographic（GC） method was established for the determination of three kinds of mono-glycerates（e.g.glycerate monocaprylin，glyceryl monodecanoate and glycery monolaurate） in bread.The sample was extracted with dichloromethane-n hexane（1∶1）.The extract was concentrated，then extracted with acetonitrile saturated with n-hexane，and detected by GC with the external standard method.The calibration curves for three mono-glycerates were linear in the range of 20-1 000 mg/L with correlation coefficients more than 0.999.The limits of quantitation of 3 monoglycerides are 12.8-35.2 mg/kg.The spiked recoveries were in the range of 81.1%-95.7% with RSDs of 2.9%-8.8%.The method has the advantages of simple operation，high sensitivity，good reproducibility and selectivity，and could meet the requirements for trace analysis of three monoglyceride in bread.关键词：gas chromatography（GC）;bread;mono-glycerate
- 1681
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- 1082
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- 4
发布时间： - 摘要：A Ru（bpy）2+3-based solid-state electrochemiluminescence（ECL） sensor was fabricated successfully.Firstly,Ru（bpy）2+3/Pt nanoparticles（Ru-PtNPs） were obtained via electrostatic interactions between the positively charged Ru（bpy）2+3 and negatively charged Pt nanoparticles.Then,Ru-PtNPs were attached to the multi-wall carbon nanotubes（MWCNTs）-Nafion homogeneous composite film coated GCE by typical ion-exchange between the positively charged Ru-PtNPs and Nafion,electrostatic interactions between positively charged Ru-PtNPs and negatively charged MWCNTs in Nafion.As a result,a large amount of luminescence probes Ru（bpy）2+3 were immobilized onto the electrode to keep their electrocatalytic activity toward the electrooxidation of tripropylamine（TPA）.The characteristic of the proposed sensor was investigated by cyclic voltammetry（CV）,scanning electron microscope（SEM） and electrochemiluminescent（ECL） method.The ECL sensor showed a good linear response to concentration of TPA in the range of 6.67×10-7-1.00×10-3 mol?L-1 with a detection limit（S/N=3） of 3.3×10-7mol?L-1.关键词：electrochemiluminescence;Nafion;multi-wall carbon nanotubes;Ru-PtNPs;tripropylamine
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- 1064
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- 2
发布时间： - 摘要：A method was developed for the qualitative and quantitative analysis of DINCH in plastics by GC-MS.The key fragmentation processes of the mass spectrum were elucidated based on the mass spectrum theory,and the fragmentation experiment of these ions could provide theoretical knowledge for the rapid identification of the existence or not of DINCH in plastics.Based on the comparison of extraction efficiencies of different organic solvents,dichloromethane was used as extraction solvent in the method.The test result showed that the method had a good linear relationship（r=0.998）in the range of 0.24-1.60 mg/L.The limit of quantitation（LOQ,S/N=10） was 1.2 mg/kg.At spiked levels of 80-400 mg/kg in plastics（PE,PP,PU,PVC）,the average recoveries were in the range of 82%-113%,with relative standard deviations of 1.1%-9.0%.The method was applied in the determination of DINCH in plastics samples with satisfactory results.关键词：1,2-cyclohexane dicarboxylic acid ester;mass spectrometry;fragmentation process;GC-MS analysis
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- 1
发布时间： - 摘要：An overview of domestic and foreign recent status on bio-oil analysis and characterization was presented,which focused on the applications of some spectroscopy and chromatography techniques in chemical structure characterization of the small organic molecules,such as,Fourier transform infrared spectroscopy（FTIR）,nuclear magnetic resonance（NMR）,mass spectrometry（MS）,gas chromatography（GC）,high performance liquid chromatography（HPLC） techniques,as well as the one and two-dimensional chromatography coupling technology.The evaluations on the role and value of these techniques in structure characterization were afforded,and the detailed descriptions of the quality standards and some typical analysis methods of bio-oil were involved,and then the effects of physical and chemical properties of bio-oil on its separation and analysis were discussed.Moreover,the structure characterizations of oligosaccharide and pyrolytic lignin remained in bio-oil were introduced.Finally,the main problems existed in bio-oil separation and analysis were summarized,and the prospect on the development trend for bio-oil separation and analysis was presented.关键词：bio-oil;separation;analysis;energy;biomass
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