最新刊期
卷 30 ， 期 1 ， 2011
- 摘要：A polystyrene based gel filtration chromatographic method was established for the isolation and examination of condensation impurity in cefuroxime sodium.The sample was separated with MKF GPC 100（100 mm×78 mm,5 μm） column uisng 001 mol/L phosphate buffer（pH 70）-acetonitrile（70∶30,by volume） as mobile phase.The flow rate was set at 10 mL/min and the detecting wavelength was set at 254 nm.The result indicated that the cefuroxime sodium was successfully separated from condensation impurity in 10 min.The method showed the advantages of simplicity and rapidness.关键词：polystyrene gel;MKF GPC 100;cefuroxime sodium;condensation impurity
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发布时间： - 摘要：Based on the fact that both the maximum wavelength of the absorption spectrum of May Grunwald′s stain(MGS) and the corresponding absorbance varied when MGS interacted with the large biological molecules of RNA under weak acidic medium,a novel spectrophotometric method for the determination of RNA was proposed. The effects of the acidity of B-R buffer solution,the amount of MGS,the amount of B-R buffer and the time on the interaction of the system were studied in detail and optimized. The decreased absorbance of MGS has a linear relationship with the content of RNA in the range of 0-08 mg/L and the correlation coefficient was 0999 6. The method is simple，rapid,highly sensitive and selective. It was applied for the determination of RNA in synthetic samples with satisfactory result. The reaction mechanism was preliminary studied.关键词：RNA;May Grunwald′s stain;spectrophotometry;electrostatic association
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发布时间： - 摘要：When β cyclodextrin(β CD) was used as a catalyst for the oxidation of benzyl alcohol in water，benzyl alcohol and the oxidative product benzaldehyde could coexist stably in the cavity of β CD.The stable inclusion of β CD and benzyl alcohol(benzaldehyde) could be automatically formed in water with a molar ratio of 1∶1，and the standard Gibbs functions of molar reaction ΔγGmθ(298 K) of benzyl alcohol(benzaldehyde) were -10417 kJ/mol and -9741 kJ/mol，respectively.The ultraviolet absorption spectra of benzyl alcohol and benzaldehyde indicated that the presence of β CD could result in the enhancement of absorption intensities of benzyl alcohol and benzaldehyde.A good linearity was obtained between the UV-absorption intensity of the system and the concentration of benzyl alcohol(benzaldehyde).Based on this，a novel enlarged ultraviolet absorption spectrometry method for the determination of aromatic organic compounds was established.The precision of this quantitative determination could reach up to 98% or more，and the determination ranges were also greatly improved.A quick and accurate method was provided for the monitoring of reaction systems in the aqueous β CD solution.关键词：β cyclodextrin(β CD);inclusion complex;spectral analysis;quantitative determination
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发布时间： - 摘要：Enantioseparation of amlodipine besylate on Chiralcel OJ chiral column was studied.The influences of different carbon number，alcohol modifier types with different three dimensional structures and concentrations,flow rate and column temperature on the enantioseparation of amlodipine besylate were investigated.And the chiral recognition mechanism for amlodipine was discussed by the chromatographic retention and thermodynamic parameters.A good baseline resolution was obtained for the separation of amlodipine besylate using hexane-isopropanol（90∶10,by volume） as mobile phase with flow rate of 04 mL/min and column temperature of 20 ℃.The resolution of amlodipine was up to 3228.In the experimental temperature range，Van′t Hoff curve with a good linearity was acquired by ploting lnα to 1/T.The enthalpy change difference，entropy change difference and Tiso of the enantioseparation on chiral column were calculated.The enantioseparation meeting the requirements of ‖ΔΔH0‖>‖ΔΔS0‖ showed that the process of chiral sepatation was an enthalpy controlled process.关键词：Chiralcel OJ column;amlodipine besylate enantiomers;chromatographic retention;chiral separation
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发布时间： -
Analysis of Pyridinium Ionic Liquid Cations by Ion Chromatography with Direct Conductivity Detection
摘要：A method of ion chromatography and direct conductivity detection was established to determine three pyridinium ionic liquid cations,eg 1 ethyl pyridinium cation(EPy+),1 butyl pyridinium cation(BPy+) and 1 hexyl pyridinium cation(HPy+).The effects of eluent types,eluent concentration and column temperature on retention of the cations were investigated with sulfonic acid base cation exchange column using ethylenediamine-citrate acid-acetonitrile as eluent.The result indicated that,with the increase of column temperature,the retention times of pyridinium cations were reduced,so the retention process of pyridinium cations is exothermic.The retentions of pyridinium cations accord with carbon number rule.The optimum chromatographic conditions were as follows:mobile phase:02 mmol/L ethylenediamine-03 mmol/L citrate acid-3% acetonitrile(pH 44);flow rate:10 mL/min;column temperature:45 ℃.Under the optimum conditions,three pyridinium cations were successfully separated.The detection limits(S/N=3) for EPy+,BPy+and HPy+were 060,159,108 mg/L,respectively.Relative standard deviations(n=5) for peak areas were less than 12%.The method was applied in the determination of pyridinium ionic liquids synthesized in chemical laboratory with spiked recoveries of 100%-104%.The good linearity and repeatability of the method made it meet the requirements of quantitative analysis.关键词：ionic liquids;ion chromatography;conductivity detection;alky pyridinium- 2377
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- 1534
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- 14
发布时间： - 摘要：In this paper,a wavelength selection-direct standardization（WSDS） algorithm was proposed for calibration transfer of NIR model.The WSDS is one of the modifications of direct standardization（DS）.In WSDS,only the wavelengths which were highly correlated with the sample property were selected for correcting the variations of the instrumental responses of two different NIR spectrometers.The corrected spectroscopic data were then used to build the model for analysis.The application of WSDS algorithm to calibration transfer of NIR analysis was evaluated by analyzing the jet fuel with different NIR spectrometers.The results showed that after the WSDS correction,the squared error of prediction（SEP） of the density of jet fuel decreased from 0004 6 to 0001 2 and that of the viscosity（20 ℃） of jet fuel decreased from 0058 6 to 0020 9.The results showed that this method can well correct the difference between instruments and improve the analytical accuracy.The corrected results,obtained by WSDS,direct standardization（DS） and piecewise direct standardization（PDS）,respectively，for jet fuel with different NIR spectrometers indicated that the former gave the best analytical accuracy.关键词：near infrared;calibration transfer;wavelength selection;direct standardization;jet fuel
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发布时间： - 摘要：A novel PTA-MMT and［BMIM］PF6 modified glassy carbon electrode（PTA-MMT-［BMIM］PF6/GCE） was prepared and successfully used for the determination of paraquat（PQ）.The modified film was characterized by infared（IR） spectrometry.The charge transfer resistance of PQ on PTA-MMT-［BMIM］PF6/GCE was the lowest by comparing the nyquist plots of the electrode before and after modification.The cyclic voltammetric behavior of PQ on modified electrode was studied. The results showed that，in pH 80 phosphate buffer solution（PBS），two pairs of redox peaks were observed on the modified electrode.The oxidation peak current was linear to scan rates in the range of 40-360 mV?s-1，indicating that the electrode process of PQ was controlled by absorption.The reaction electronic number and active area of PQ on PTA-MMT-［BMIM］PF6/GCE were obtained to be 2 and 0064 4 cm2，respectively.The effects of modifier dosage，buffer solution types and pH values for the determination of PQ were discussed.Under the optimized conditions，the correlation between peak current（Ipa） and PQ concentration was studied by square wave voltammetry，and a good linear relationship was obtained over PQ concentration in the range of 50×10-7-25×10-4 mol?L-1.The linear equation was Ipa（μA）=-1024-23683c（r=0999 3） and the detection limit was 207×10-7 mol?L-1.The spiked recoveries were in the range of 93%-104%.The modified electrode exhibited good repeatability and stability.关键词：ionic liquid;montmorillonite(MMT);paraquat（PQ）;square wave voltammetry
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发布时间： - 摘要：A new method based on solid phase extraction and ultra performance liquid chromatography-tandem mass spectrometry（UPLC-ESI MS/MS） was developed for the determination of 9 sulfonylurea herbicides（metoxuron, foramsulfuron, cinosulfuron, methabenthiazuron, prosulfuron, linuron, ethoxysulfuron, chloroxuron and cyclosulfamuron） in corn. The corn sample was soared in water, and then extracted with methanol-acetone （1∶1, by volume）. The extract was cleaned up by C18 solid phase extraction cartridge. The eluent was evaporated to near dryness under a stream of nitrogen gas, and redissolved by methanol. The identification and detection of target compounds were achieved under multiple reactions monitoring （MRM）mode with positive electrospray ionization（ESI）. 9 sulfonylurea herbcides were quantified by external standard method. The calibration curves of 9 sulfonylurea herbicides were linear in the range of 005-20 mg?L-1 with correlation coefficients more than 099. The limits of detection （LOD, S/N=3） and the limits of quantitation （LOQ, S/N=10） were in the range of 0001-0005 mg?L-1 and 0062-0080 mg?kg-1, respectively. 1LOQ, 2LOQ and 5LOQ were chosen as the three spiked levels of recovery for the method. The recoveries of 9 sulfonylurea herbicides ranged from 60% to 85% with relative standard deviations less than 10%. The method was simple and effective, and could meet the requirements the simultaneous determination of 9 sulfonylurea herbicides in corn sample.关键词：SPE;ultra performance liquid chromatography-tandem mass spectrometry;sulfonylurea herbicides;corn
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发布时间： - 摘要：A simple and sensitive high performance liquid chromatographic（HPLC） method was developed for the simultaneous determination of 9 nicotinoid insecticide residues,including dinotefuran，nitenpyram，flonicamid，thiamethoxam，imidacloprid,clothianidin，imidaclothiz，acetamiprid and thiacloprid,in sulphur containing vegetables samples. The extract efficiencies of several solvent and the cleanup capacities of different SPE cartridges were compared. The vegetables were extracted with acetonitrile and cleaned up on an Envi-Carb/PSA cartridge. The nicotinoid insecticides were eluted with acetonitrile and detected with UV detector. The calibration curves showed good linearities in the range of 002-10 mg/L with correlative coefficient more than 0999. The limits of quantitation（LOQ） were 002 mg/kg for all 9 pesticide except for thiacloprid with LOQ of 005 mg/kg. The recoveries of 9 pesticides from vegetable sample spiked at three concentration levels of 002 mg/kg,005 mg/kg and 05 mg/kg ranged from 67% to 110% with RSDs less than 186%. The established method was simple,sensitive and accurate,and was suitable for the routine detection of nicotinoid pesticides residues in vegetables.关键词：nicotinoid residue;insecticide;HPLC;SPE;vegetable
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发布时间： - 摘要：A simple and green way was used to control the crystallization of calcium carbonate in the sucrose/L arginine system.The growth orientation,morphology and polymorph of calcium carbonate crystal were studied.XRD analysis showed that the crystals were mainly vaterite and a small amount of calcite formed in the sucrose/L arginine system.However，only the vaterite crystals were formed in the separate sucrose solution or L arginine solution.SEM analysis showed that sucrose or L arginine could induce the formation of calcium carbonate with a special morphology.The experimental results showed that sucrose/L arginine had a better controll for the growth orientation of calcium carbonate as well as its morphology and polymorph.The method provided a positive guidance for the synthesis of biomimetic materials.关键词：sucrose;arginine;calcium carbonate;biomimetic synthesis
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发布时间： - 摘要：In pH 30 Britton-Robinson buffer,sulfur chlorophenol N bonded with Cu(Ⅱ) to form a blue complex,and the complex reacted with protein to form a dark blue multi complex at room temperature which presents a maximum absorption at 724 nm and a red shift of 174 nm comparing with that of sulfur chlorophenol N.A new method for the determination of proteins was established based on the reaction of multi compound substance.The spectral characterisitics of the system and its influencing factors were investigated.Under the optimal conditions,the apparent molar absorptivity and linear range for HSA were 306×105 L?mol-1?cm-1 and 20-120 mg?L-1,respectively.With the presence of polyoxyethylene octyphenyl ether(OP),the sensitivity of the method could be increased by 31%.The mehtod was applied in the determination of urine protein with satisfactory results.And the sensitivity of the method is 16 times higher than that of the Biuret method.关键词：spectrophotometry;sulfur chlorophenol N-Cu(Ⅱ) complex;urine protein
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发布时间： - 摘要：A high performance liquid chromatography-electrospray ionization trap mass spectrometric method was established for the determination of 8 hydroxy 2′ deoxyguanosine（8 OHdG） in urine.The sample was concentrated with WCX cartridge column and eluted out with 05%firmic acid-methanol.The elute solution was evaporated to dryness in N2 flow and redissolved with 05 mL mobile phase.The analysis of 8 OHdG was carried out using fragment ion of m/z 116 and 1674 as qualitative ions,and m/z 1674 as quantitative ion.The method showed good linearity over the range of 50-5000 μg/L for 8 OHdG with a correlation coefficient of 0999 4.The detection limit（S/N=3） was 050 μg/L.The spiked recoveries of 8 OHdG at two concentration levels of 400 μg/L and 1000 μg/L were 82% and 76%,respectively.The proposed method was suitable for the determination of 8 OHdG in urine sample with high selectivity and sensitivity.关键词：high performance liquid chromatography;ionization trap mass spectrometry;8 hydroxy 2′ deoxyguanosine;urine
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发布时间： - 摘要：A new ［BMIM］PF6-MnO2-CHIT/GCE modified electrode was fabricated via the chitosan（CHIT） filming using hydrophobic ionic liquid 1 butyl 3 methylimidazolium hexafluorophosphate（［BMIM］PF6） and nano MnO2 as modifiers.In Britton-Robinson（B-R） buffer，the electrochemical behavior of baicalin at ［BMIM］PF6-MnO2-CHIT/GCE was studied，and a new method for the determination of baicalin in radix scutellariae was developed.The cyclic voltammetry curves of baicalin at ［BMIM］PF6-MnO2-CHIT/GCE presented a pair of sensitive and reversible redox peaks.The peak current responsed at the proposed electrode was enhanced 26 folds higher than that at the MnO2-CHIT/GCE，and the peak potential difference was 0062 V，the electron transfer rate constant ks was 0258 s-1.The change of the oxidation peak current with baicalin concentration at ［BMIM］PF6-MnO2-CHIT/GCE was examined by differential pulse voltammetry.The calibration curve was linear in the concentration range of 10×10-9-10×10-5 mol/L with a detection limit（S/N=3） of 10×10-10 mol/L.The relative standard deviation（n=5） of 10×10-8 mol/L baicalin was 21%.The method was applied in the determination of baicalin in samples with satisfactory results，and the spiked recoveries were in the range of 95%-103%.关键词：［BMIM］PF6;nano MnO2;baicalin;cyclic voltammetry;differential pulse voltammetry
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发布时间： - 摘要：A gas chromatography-mass spectrometric method was developed for the determination of acrylonitrile in cosmetic samples.The cosmetics were ultrasonically extracted with methanol and then centrifuged.The concentrated supernatant was purified with an Oasis HLB solid phase extraction cartridge using 20% methanol solution as washing agent and 80% methanol solution as eluting agent.The eluent was further dehydrated with anhydrous sodium sulphate.The analysis was carried out with a capillary column（HP INNOWax 60 m×025 mm×050 μm） under electron ionization conditions at a flow rate of 12 mL/min.The quantitation was performed by the external standard method under selected ion monitoring（SIM） mode using monitering ions of m/z 53,52 and 26.The recoveries were in the range of 84%-101% with relative standard deviations（RSDs） of 11%-42%.The detection limit was 04 mg/kg.This method was proved to be simple，accurate，and was suitable for the determination of acrylonitrile in cosmetics.关键词：cosmetics;acrylonitrile;solid phase extraction;gas chromatography-mass spectrometry
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- 1463
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发布时间： - 摘要：The tests of single factor,orthogonal and verification to separate and purify chlorogenic acid from honeysuckle crude extracts by NKA 2，D1400，polyamide，HP2MGL，ADS 21，D101 and AB 8 seven macroporous resin were carried out in sequence,and the best processing parameters were optimized based on the adsorption and desorption results.The results showed that NKA 2 was the best resin,whose static saturated adsorption capacity was 21217 mg/g,and desorption rate by 90% ethanol reached 814%.The best processing parameters for separating and purifying chlorogenic acid from honeysuckle crude extracts by NKA 2 resin were as follows:sample concentration:4 g/L,sample volume:35 BV,sample flow rate:3 BV/h,elution ethanol concentration:80%,elution volume:3 BV,and elution flow rate:1 BV/h.Under the optimal conditions,the yield rate of chlorogenic acid reached 8579%,and its purity was 4550%.When using sample concentration of 3 g/L,sample volume of 45 BV,sample flow rate of 2 BV/h,elution ethanol concentration of 80%,elution volume of 3 BV and elution flow rate of 3 BV/h,the purity of chlorogenic acid reached 5307%,and its yield was 7333%.Comparing with the current separating and purifying process of chlorogenic acid from honeysuckle crude extracts,the optimized process has better practical and reference value.关键词：honeysuckle flower;chlorogenic acid;macroporous resin;static adsorption;dynamic adsorption;separation and purification
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发布时间： - 摘要：In alkaline medium,gold nano particle could catalyze the chemiluminescence（CL)of the luminol-potassium permanganate system,and the presence of ceftazidime could enhance the CL intensity of this system.Based on this,a flow injection CL method for the determination of ceftazidime was established.Under the optimized conditions,the linear range for determination of ceftazidime was in the range of 30×10-5-50×10-2 g/L with a detection limit of 10×10-5 g/L.The relative standard deviation（RSD,n=11) was 20％ for 40×10-3 g/L ceftazidime.The method was applied in the determination of ceftazidime in injection with satisfactory results.关键词：chemiluminescence;flow injection analysis;luminol;ceftazidime;gold nano particle
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- 1587
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发布时间： - 摘要：A solid phase extraction coupled with high performance liquid chromatographic（SPE/HPLC） method was established for the determination of 4 kinds of sodium n alkyl benzene sulfonates in water.The samples were refrigerated and centrifuged，then purified and enriched with MAX complex anion exchange column.Four sodium n alkyl benzene sulfonates were successfully separated by HPLC using acetonitrile-100 mmol/L ammonium acetate（73∶27，by volume） as mobile phase with a flow rate of 1 mL/min，column temperature of 30 ℃，detection wavelength of 225 nm and injection volume of 10 μL.Under the optimal conditions，the calibration curves were linear in the range of 10-50 mg/L for sodium undecylbenzene sulfonte and sodium N tridecylbenzene sulfonate with detection limits of 10 mg/L，and 5-25 mg/L for sodium dodecylbenzene sulphonate and sodium tetradecylbenzene sulfonate with detection limits of 5 mg/L.The spiked recoveries were in the range of 86%-98% with relative standard deviations（RSDs） of 29%-74%.关键词：high performance liquid chromatography;solid phase extraction;alkyl benzene sulfonate
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- 1636
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发布时间： - 摘要：An ion chromatographic method in combination with pulsed amperometric detection was developed for the analysis of added iodide and iodate in infant formula cereal products.The protein removal mode and the amount of protein precipitant were studied.The opitimun conditions for ultrasonic extraction were explored and the dosage of reductant for iodate to iodide was investigated.Under the optimum conditions,the method showed good linearity in the range of 1-100 μg/L for iodide and iodate with correlation coefficients of 0999 1 and 0999 9,respectively.The quantitation limits were 52 ng/g and 90 ng/g,respectively.The spiked recoveries for iodide and iodate were in the range of 74%-100% and 75%-100%,respectively,with RSDs of 44%-67% and 50%-69%,respectively.关键词：ion chromatography;iodine content;infant formula cereals;iodide;iodate
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- 5
发布时间： - 摘要：The components extracted from Chinesechive by different solvents，such as petroleumether，chloroform，dichloromethane，acetone and ethylacetate were detected by GC-MS.The results showed that various sulfocompounds were obtained in solvent extracts，such as dimethyl disulfide,dimethyl trisulfide,S methyl methanethiosulfinate,sulfuric acid,dimethyl ester，disulfide,methyl 2 propenyl and heterocyclic,etc.Some rather complicated substances as 3 vinyl 12 dithiacyclohex 5 ene,were also detected.At low temperature，the kinds of detected substances at stem and leaf extracted with petroleumether，chloroform，dichloromethane，acetone and ethylacetate were 21，27，10，9，15 and 14，6，9，3，9,respectively.At high temperature，the detected substances at stem and leaf were 92，73，22，126，47 and 29，18，undetected，24，9,respectively.The kinds of main compounds at different parts of Chinesechive and different temperatures were different.The extractives from Chinesechive stem were excessive and complex.The compounds detected at high temperature were more than that at low temperature.The effect of solvent extractives on Fusarium oxysporum f.sp.cubense spore was also investigated.The result indicated that some chemical compositions existed in solvent extractives from Chinesechive with inhibitory action on the germ.关键词：Chinesechive;extract;GC-MS;Fusarium oxysporum f.sp.cubense;germination
- 1903
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- 1353
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- 6
发布时间： - 摘要：In this paper，several extraction methods of organochlorine pesticides（OCPs），including homogenization，solid phase extraction，solid phase miroextraction，accelerated solvent extraction，pressured fluid extraction，supercritical fluid extraction，ultrasonic solvent extraction，soxhlet extraction，microwave assisted extraction，liquid-liquid extraction and matrix solid phase disperse，were introduced and classfied based on the properties of the matrixes.The advantages and disadvantages of those techniques were analyzed and compared.The development trends of extraction methods for OCPs were prospected.关键词：organochlorine pesticides;extraction techniques;matrix
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