最新刊期
卷 31 ， 期 8 ， 2012
- 摘要：The interactions between lysozyme and hydroxy-functionalized ionic liquids including 1-（2,3-dihydroxypropyl）-3-methylimidazolium chloride（［2,3-dhpmim］Cl）,1-（2,3-dihydroxy-propyl）-3-methylimidazolium tetrafluoroborate（［2,3-dhpmim］BF4）and 1-（2,3-dihydroxypropyl）-3-methylimidazolium hexafluorophosphate（［2,3-dhpmim］PF6）were studied by UV-Vis absorption and fluorescence spectra.The results indicated that the fluorescence quenching of lysozyme by hydroxy-functionalized ionic liquids performed in static quenching mode.The synchronous fluorescence spectra showed that the microenvironment of tryptophan residues was changed.The binding constants and binding sites of ionic liquids to lysozyme increased by the order of ［2,3-dhpmim］Cl关键词：Hydroxy-functionalized ionic liquid;lysozyme;fluorescence quenching;interaction
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发布时间： - 摘要：Through repeated freezing and thawing of cell，ammonium sulfate precipitation and hydroxyapatite chromatography，the phycocyanin was extracted from spirulina platensis and its purity could reach up to A620/A280=4.1.UV-visible spectra and fluorescence emission spectrometry were used to study the spectral characterisitic of the protein.The results showed that the absorption peaks of the purified protein were located at 280，360,620 nm and the maximum emission wavelength was 650 nm.Using this phycocyanin as fluorescence probe，a new approach was developed for the sensitive and selective determination of divalent mercury ions based on fluorescence quenching.Different influence factors，including pH value，reaction time，temperature and phycocyanin concentration，were investigated.In 0.05 mol/L KH2PO4-Na2HPO4 ,at a pH value of 7.5，phycocyanin concentration of 3 mg/L，reaction time of 30 min and reaction temperature of 30 ℃，the relative fluorescence intensity decreased linearly with mercury ions concentration in the range of 0.1-10 μmol/L.The detection limit was 0.056 μmol/L.This approach displayed a good selectivity to mercury ions.When concentration ratio of interference ions to mercury ion reached to 40∶1，several kinds of coexistence ions had little influence on the detection of mercury ion.This new method exhibits a bright application prospect in the detection of mercury ions due to its advantages of good simplicity，sensitivity，reproducibility and pro-environment.关键词：phycocyanin;fluorescence quenching;Hg2+ sensing
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发布时间： - 摘要：A pretreatment method to enrich trace element Pb in corals was established with AG1-X8 anion exchange resin and self made PTFE micro column,then Pb isotopic ratios in Hainan corals（porites lutea） in China was measured by high-resolution inductively coupled plasma mass spectrometry（HR-ICP-MS）.Several parameters including procedural blank,elution curve,Pb recovery and matrix separation were compared among four different eluents,and the results showed 0.50 mol/L HNO3 was the best eluent,of which the procedural blank was 18 pg,and recovery of Pb was 99.6%,besides,there was no tailing observed and more than 99.8% of the matrix elements in corals such as Ca,Sr,Mg,Fe,Mn,U,Ba as well as Zn could be well separated from Pb during the eluting process.After eluted with 0.50 mol/L HNO3,207Pb/206Pb and 208Pb/206Pb in Hainan corals was determined to be 0.850 5 and 2.087 0,with RSDs（n=21） of 0.12% and 0.11%,respectively.All the values were located between two warning lines,which indicated the quality control was acceptable and the pretreatment method was reliable.The method established could be applied in the determination of Pb isotopic ratios in corals and other similar samples.关键词：HR-ICP-MS;anion exchange resin;separation & preconcentration;lead;isotopic ratios;coral
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发布时间： - 摘要：A rapid and effective method was developed for the determination and confirmation of five organotins，including n-butyltin-trichloride（MBT），dibutyltin-dichloride（DBT），chlorotributyl-stannane（TBT），Di-n-octyldichlorotin（DOT） and triphenyltin（TPhT），in textiles by gas chromatography tandem mass spectrometry（GC-MS/MS）.The target compounds were extracted，derivatized and liquid-liquid extracted with hexane.The qualitative and quantitative analyses were carried out by GC-MS/MS under selected reaction monitoring（SRM） mode.The test result showed that five organotins had good linear relationships（r>0.999） between 0.02 mg/L and 0.50 mg/L.The limit of quantitation（LOQ，S/N≥10） of five organotins were between 0.03 mg/kg and 0.05 mg/kg.At the spiked levels of 0.05-0.5 mg/kg in five kinds of negative samples（e.g.cotton，real silk，wool，polyester and cotton/nylon），the average recoveries of five organotins were in the range of 82%-110%， with relative standard deviations（RSD，n=5） of 2.1%- 7.5%.With high sensitivity，selectivity and good precision and accuracy,this established method could make up the shortage of confirmations by GC and GC-MS，and was suitable for the determination of different structures of organotin compounds such as mono-substituted，di-substituted and tri-substituted organotin compounds etc.，compensating for the limitation of the LC-MS/MS method which could only detect tri-substituted organotin compounds.关键词：GC-MS/MS;organotins;textiles;determination;confirmation
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发布时间： - 摘要：A new mesoporous carbon nanofibers modified pyrolytic graphite electrode（MCNF/PGE） was prepared and applied in the electrochemical determination of rutin.The characteristics of MCNF/PGE and the electrochemical behavior of rutin on the modified electorde were investiged by different methods including cyclic voltammetry,electrochemical impedance spectroscopy and differential pulse voltammetry.The results showed that MCNF/PGE had a good electrocatalytic response to the electron transfer of ［Fe（CN）6］3-/4-.The system presents features corresponding to a diffusion-controlled process of rutin on the surface of MCNF/PGE.Compared to the bare PGE,the proposed modified electrode possesses a high electrocatalytic activity towards the redox of rutin because of the large amount of edge plane-like defects,the large surface area and the mesoporous structure of MCNFs.The anodic peak current（Ipa） of rutin at the MCNF/PGE is 18-fold higher than that of the bare PGE.Under the optimal conditions,the anodic currents of rutin are linear with its concentrations（C） in the range of 2.0×10-8-1.2×10-6 mol/L with a detection limit（S/N=3） of 5.0×10-9 mol/L.The linear equation is Ipa（μA）=-0.415 + 39.104 c（μmol/L）,with a correlation coefficient of 0.999.In addition,the electron transfer coefficient（α）,standard rate constant（ks） and the redox mechanism of rutin at the modified electrode were calculated.The MCNF/PGE exhibited distinct advantages of simple preparation,surface renewal,good reproducibility and good stability,and can beused as a good electrochemical sensor for the determination of rutin in real tablet analysis.关键词：mesoporous carbon nanofibers;chemically modified electrode;rutin;voltammetry;electrocatalysis
- 1968
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发布时间： - 摘要：A new radio frequency(RF) power supply was developed,which composed of the module of signal generating and amplifying,the module of amplitude adjusting and the module of power driving.The power supply is compact,small size,stable and low cost,and is divided into low-frequency part and high-frequency part to drive two radio frequency quadrupoles in home-made time-of-flight mass spectrometer.The tunable frequency range of RF power supply are 150-900 kHz in low-frequency and 1-2 MHz in high frequency,the adjustable range of peak to peak voltage Vp-p are 0-100 V in low-frequency and 0-1 400 V in high frequency.With the RF power supply described in this paper,the home-made time-of-flight mass spectrometer was used to test the samples.As a result,the ions with m/z of 50-1 200 could be stably measured,and a good linearity was obtained in the concentration range of 5.0×10-9-5.0×10-5 mol/L for samples.关键词：radio frequency power supply;radio frequency quadrupole(RFQ);time-of-flight mass spectrometer(TOF MS)
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发布时间： - 摘要：A label-free approach to qualify and quantify bovine serum albumin（BSA） based on the information of mass spectrum was reported.The conditions of high-performance liquid chromatography（HPLC） were optimized,including program of gradient elution and flow rate.The content of BSA was determined in optimal conditions by HPLC-quadrupole-time of flight tandem mass spectrometry（Q-TOF）after digested with trypsin in-solution.The data was processed with MassHunter Qualitative Analysis software.The setting parameters of software were optimized to decrease the probability of false positive results.The reproducibility of the experiments was investigated.According to the peak area results of eight peptides,the RSDs（n=4） were below 3.0%.The detection limit for BSA was achieved as 100 ng.The results also indicated that there was a logarithmic manner between concentration of protein and sequence coverage of peptides.Among the eight peptides of BSA with higher abundance,one unique peptide:HLVDEPQNLIK was selected to qualify the BSA,and another unique peptide:ATEEQLK was used to quantify the BSA.The recovery of this method was calculated to be 106%.This method is simple,rapid,low cost and specific,and could be employed for screening characteristic peptides of specific proteins and detecting of complex biological sample.关键词：quadrupole-time of flight tandem mass spectrometry;label-free quantitation;BSA
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发布时间： - 摘要：An simple operation and high sensitivity method without internal standard was developed for the quantitative analysis of oxidized triacylglycerol polymers(TGP).Polar compounds(PC) were obtained from 1 g oil sample by preparative flash chromatography(PFC)(flash silica column,20 g,particle size:40-60 μm,pore size:6 nm) and subsequently separated by a high-performance size-exclusion chromatography(GPC column,Φ7.8 mm×300 mm,particle size:5 μm,pore size:10 nm ) into oxidized triacylglycerol polymers(TGP),oxidized triacylglycerol dimers(TGD),oxidized triacylglycerol monomers(ox-TGM),diacylglycerols(DG) and free fatty acids(FFA).By quantitation of PC in oil through gravimetric determination and TGP in PC through area normalization method,TGP content in oil was calculated.The results showed that the calibration curves for TGO and TGD were linear in the concentration ranges of 28-1 800 mg/L and 11-2800 mg/L,respectively,with correlation coefficients(r2) more than 0.99.Their LODs were 28 mg/L and 11 mg/L,respectively,and LOQs were 113 mg/L and 44 mg/L,respectively,which was equivalent to 0.01% for LOQ of TGP in oil.The RSDs of TGP in oil detected by PFC-HPSEC were less than 10%.The recoveries at spiked levels of 2.27%,8.47% and 30.94% ranged from 95% to 98% with RSDs less than 4%.In detecting TGP in oil,PFC-HPSEC matched traditional silica column well with RE of 0-8.9%.The method could be used in the determination of TGP in all kinds of oil samples,including used cooking oil and unused edible oil,especially for virgin oil and refined oils and fats with low levels of TGP.关键词：oils and fats;oxidized triacylglycerol polymers(TGP);polar compound(PC);preparative flash chromatography(PFC);high-performance size-exclusion chromatography(HPSEC);gel permeation chromatography(GPC)
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发布时间： - 摘要：An amperometric biosensor for the detection of organophosphorus pesticide was developed based on layer-by-layer self-assembly both acetylcholinesterase(AChE) and gold nanoparticles(AuNPs) on glassy carbon electrodes（GCE) in the presence of poly(diallyldimethylammonium chloride)（PDDA).The electrochemical properties of the biosensor were investigated by electrochemical impedance spectroscopy and differential pulse voltammetry.The proposed biosensor exhibited a high affinity to the substrate of AChE and produced a detectable and fast response owing to its excellent electron transfer rate and satisfactory biocompatibility of AuNPs.Compared with that at the unmodified electrode,the peak current of thiocholine at the proposed biosensor obviously increased.Under the optimum conditions,the inhibition rate of methyl parathion to the immobilized AChE was proportional to the logarithm of concentration of methyl parathion over the range of 4.6×10-5 – 5.3×10-3 mol/L with a detection limit of 7.6×10-6 mol/L.The proposed biosensor was successfully applied in the determination of methyl parathion in vegetable sample,which means that the proposed biosensor provides a new promising tool for the pesticide analysis.关键词：biosensor;self-assembly;acetylcholinesterase;gold nanoparticles;organophosphorus
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发布时间： - 摘要：A novel method was developed for the simultaneous determination of 11 sulfonamides in veterinary pharmaceutical powder by high performance liquid chromatography-diode array detection.The sample was extracted with 95% acetonitrile solution and then purified by an Alumina-B solid phase extraction cartridge.The extraction residue was redissolved in 15% acetonitrile solution and separated on a TC-C18 chromatographic column.The mobile phase was composed of 0.017 mol/L phosphoric acid and acetonitrile and a gradient elution program was carried out.The diode assay detection was used for the qualitative and quantitative analysis.The results indicated that the chromatographic peaks of 11 sulfonamides drugs and their corresponding spectra were ideal under the optimal conditions.The calibration curves of 11 analyte were linear in the range of 0.25-10.0 mg/L.The average recoveries of 11 sulfonamides at three spiked levels of 0.5,1.0,5.0 mg/kg were between 67% and 97%,with relative standard deviations ranged from 1.5% to 9.9%.Based on signal to noise ratio（S/N=3） and the corresponding spectra,the limits of detection of 11 analytes in veterinary pharmaceutical powder were all 0.25 mg/kg.关键词：sulfonamides;high performance liquid chromatography;diode array detection;veterinary pharmaceutical powder;qualitative and quantitative analysis
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发布时间： - 摘要：Some investigations indicated that triclosan（TCS）has a genetic toxicity and would induce DNA damage.In this paper,a variety of spectroscopic methods，including UV spectrum,fluorescence spectrum and circular dichroism spectrum,were used to study the interaction of triclosan with human tumor related DNA（p53 DNA and C-myc DNA）,aiming at providing the scientific basis for triclosan-s toxicity to human tumor at the molecular level.The UV experiments,KI quenching experiments and CD experiments suggested a weak intercalation between triclosan and DNA;Besides,melting experiments and fluorescence titration experiments also confirmed that triclosan interacts with DNA via partly interaction binding,thus affecting the double helix structure of DNA.关键词：triclosan;DNA;human tumor;spectrometry;interaction
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发布时间： - 摘要：A reversed-phase high performance liquid chromatographic method was developed for the determination of three alkaloids of Lycoris radiate.Chromatographic separation was performed on a ZORBAX ODS-C18 reversed phase column（150 mm × 4.6 mm，5 μm）.Effects of mobile phase,pH and flow rate on the analysis of alkaloids of Lycoris radiate were investigated.The optimized chromatographic conditions for the alkaloids of Lycoris radiate were as follows:mobile phase:09% triethylamine aqueous solution （pH 8.0 adjusted with acetic acid）（A）-acetonitrile（B）-methanol（C）,flow rate:1.0 mL /min,detection wavelength:234 nm.Under the optimal conditions,14 alkaloids were successfully separated from Lycoris radiate sample.The detection limits were 3.375 mg/L for galanthamine,0.475 mg/L for lycoramine and 0.495 mg/L for lycorine,respectively.The average recoveries were all 98%.The method was applied in the detection of three alkaloids contents in different parts of Lycoris radiate.The result indicated that the contents were significantly different in different parts.The highest content part of alkaloids was the leaves of Lycoris radiate.In the same part,the content of lycorine was the highest among them three,and that of galanthamine was the lowest.关键词：Lycoris radiate;high performance liquid chromatography;galanthamine;lycoramine;lycorine
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发布时间： - 摘要：The electrocatalytic oxidation behaviors and electrochemical kinetics of salbutamol(SAL) were investigated at sodium dodecyl benzenesulfonate(SDBS) self-assembled-monolayers and 1-benzy-3-methylimidazole hexafluorophosphate(［BnMIM］PF6) modified carbon paste electrode(SDBS-［BnMIM］PF6/CPE).The experimental results indicated that the SDBS-［BnMIM］PF6/CPE showed an excellent electrocatalytic activity toward SAL.The electrochemical kinetic parameters were determined by cyclic voltammetry(CV) and chronoamperometry(CA) at SDBS-［BnMIM］PF6/CPE.The catalytic oxidation peak current of SAL versus its concentration had a good linear relationship in the concentration range of 9.0×10-5-1.0×10-3 mol?L-1 and the detection limit(S/N=3) was 1.08×10-6 mol?L-1 by square wave voltammetric(SWV) method.The proposed method was successfully applied in the electrochemical quantitative determination of SAL content in commercial inhaled salbutamol solution.关键词：salbutamol;sodium dodecyl benzenesulfonate(SDBS);ionic liquid;modified carbon paste electrode;electrocatalytic oxidation
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发布时间： - 摘要：An ion-pair chromatographic method was developed for the determination of zinc 4-hydroxybenzene sulphonate in cosmetics with different matrixes.Lotion and shampoo samples were ultrasonically extracted with 20% acetonitrile aqueous solution,cream and powder samples were ultrasonically extracted with 80% acetonitrile aqueous solution,and lipstick samples were ultrasonically extracted with tetrahydrofuran and 80% acetonitrile aqueous solution,and then the extracts were centrifuged and filtered.Using tetrabutylammonium hydroxide as an ion pair reagent,the retention behavior of zinc 4-hydroxybenzene sulphonate and the optimum chromatographic conditions were investigated.The optimal conditions were as follows:stationary phase:Kromasil C18（4.6 mm×250 mm,5 μm）,mobile phase:A （5 mmol/L tetrabutylammonium hydroxide and 25 mmol/L sodium dihydrogen phosphate at pH 2.5）∶B （acetonitrile）=80 ∶ 20,flow rate:1.0 mL/min,column temperature:30 ℃,detection wavelength:230 nm.Under the optimal conditions,the quantitation limits of zinc 4-hydroxybenzene sulphonate were 24 mg/kg for lotion and shampoo,120 mg/kg for cream and lipstick,and 60 mg/kg for powder.The calibration curve of zinc 4-hydroxybenzene sulphonate was linear in the range of 0.5-50 mg/L with a correlation coefficient of 0.999 8.The average recoveries at three spiked levels were between 94% and 99%,with relative standard deviations of 0.57%-3.9%.The method was rapid,simple and accurate,and could be used for the determination of zinc 4-hydroxybenzene sulphonate in cosmetics.关键词：Ion-pair chromatography;zinc 4-hydroxybenzene sulphonate;cosmetics
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发布时间： - 摘要：A precise,sensitive and low cost method was developed for the determination of four casein(CN),e.g. αs1-CN,αs2-CN,β-CN and κ-CN,and four whey protein,e.g.α lactalbumin(α-La),β-lactoglobulin A(β-Lg A),β-lactoglobulin B(β-Lg B) and serum albumin(SA) by reversed phase high performance liquid chromatography.Skimmed yak milk was diluted with denaturing solution,and separated on a Jupiter C4 column（250 mm×4.6 mm,300，5 μm i.d.） at 20 ℃.A gradient programme was carried out at a flow rate of 0.8 mL/min using 0.1% trifluoroacetic acid（TFA） water solution and 0.1% TFA acetonitrile solution as eluent.The detection wavelength was set at 220 nm.The results showed that eight protein fractions could be completely separated within 40 min.The calibration curves were linear in the ranges of 0.56-5.6 g/L for αs1-CN,0.14-1.4 g/L for αs2-CN,1.35-13.5 g/L for β-CN,0.35-3.5 g/L for κ-CN,0.17-1.7 g/L for α-La,0.036-0.36 g/L for β-Lg A and β-Lg B,and 0.98-9.8 g/L for SA,with correlation coefficients more than 0.99 except for α-La.The spiked recoveries of eight protein fractions in yak milk sample were in the range of 86%-103% with RSDs of 1.7%-8.7%.The limits of detection（LODs） of eight protein fractions were in the range of 10.7-39.2 mg/L,and the limits of quantitation（LOQs）were 35.7-130.7 mg/L.The developed method was simple and accurate,and could meet the demands for actual application.关键词：yak milk;casein;whey protein;high performance liquid chromatography
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发布时间： - 摘要：A capillary electrophoresis/light emitting diode（LED） induced fluorescence detector system was designed and constructed especially for the determination of ephedrine and pseudoephedrine in ephedra herb.According to the spectral and chemical characteristics of ephedrine and pseudoephedrine,the main parts of apparatus were chosen as follows:a blue LED was used as the light source;two band pass filters including BP 470 filter and BP 530 filter were used for the emission light and the fluorescence,respectively,and photomultiplier tube（PMT） was used as the detection element.The buffer concentration and the separation voltage were optimized.Fluorescein isothiocyanate（FITC） was chosen as the label probe,and 10 mmol/L Na2B4O7（pH 9.3）+16 mmol/L SDS was used as running buffer.Under the optimal conditions,a baseline separation of two compouds in ephedra herb was achieved under the separation voltage of 12 kV.The method showed good linearity over the concentration range of 0.25-10 mg/L for the two compounds with correlation coefficient more than 0.99.The limits of detection（S/N=3） for ephedrine and pseudoephedrine were 0.38 μg/L and 0.29 μg/L,respectively.The intra day RSDs for ephedrine and pseudoephedrine were 2.0% and 2.2%,and the inter-day RSD were 5.4% and 5.1%,respectively.The method was successfully used in the analysis of ephedra herb with recoveries of 94% for ephedrine and 107% for pseudoephedrine.关键词：ephedrine;pseudoephedrine;capillary electrophoresis;fluorescence
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发布时间： - 摘要：A complex of dihydromyricetin-Zn(DMY-Zn)was prepared firstly，the interaction of DMY-Zn complex with DNA was investigated by using fluorescence titration that ethidium bromide(EB) as a fluorescence probe and viscosity measurements.The results indicated that DMY and Zn2+ ions are easy to form complexes which compositions were tested as ［C15H10O8Zn］?2H2O by characterization using UV-Vis，IR spectroscopy，elemental analysis and thermal gravimetric analysis(TG-DTA).With the strong interaction with DNA，the DMY-Zn complex can compete with the strong intercalator ethidium bromide to intercalate into the stacked base pairs through the intercalation which the Stern-Volmer quenching constant Ksq is equal to 1.01.关键词：dihydromyricetin - zinc complex;DNA;fluorescence spectrometry;viscosity measurements;interaction
- 1945
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发布时间： - 摘要：A gas chromatography-mass spectrometric(GC-MS) method was established for the determination of four main kinds of phytosterols(e.g.brassicasterol,campesterol,stigmasterol and β sitosterol) in vegetable oils.The phytosterols were transformed to the corresponding TMS derivatives and subsequently analyzed by GC-MS.The mass spectrometric fragmentation rule and mass characteristic ions of the derivatives were also studied.The method is accurate,reliable and convenient，and the detection limit was 0.01 g/kg.It was applied in the qualitative and quantitative determination of phytosterols in vegetable oils with satisfactory results.关键词：Vegetable-oils;phytosterols;mass fragmentation rule;gas chromatography-mass spectrometry(GC-MS)
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发布时间： - 摘要：A micellar electrokinetic capillary chromatographic method was established for the simultaneous determination of rutin,danshensu,ginsenoside Rb1,ginsenoside Rg1 and notoginsenoside R1 in Xiaoshuantongluo Tablet.The sample was extracted with methanol and separated on an uncoated fused silica capillary column(75 μm×60 cm,effective length 50 cm),using 60 mmol/L SDS-30 mmol/L Tris-10 mmol/L H3BO3(containing 15% methanol) as running buffer,with applied voltage of 25 kV.The analytes were detected by UV detecter at 214 nm.Under the optimized conditions,a baseline separation of five components was achieved in 26 min.The calibration curves were linear in the ranges of 2.5-100 mg/L for rutin,2.5-200 mg/L for sodium danshensu,10-300 mg/L for ginsenoside Rb1,15-400 mg/L for ginsenoside Rg1 and notoginsenoside R1,with detection limits of 0.3,0.9,3.0,5.0,6.0 mg/L,respectively.The average recoveries of five components were between 93% and 108% with relative standard deviations not more than 4.5%.The method was simple and accurate,and was suitable for the routine analysis of five effective components in Xiaoshuantongluo Tablet.关键词：micellar electrokinetic capillary chromatography;Xiaoshuantongluo Tablet;simultaneous determination
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- 978
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发布时间： - 摘要：Dimethoate coating was obtained by evaporating staturated dimethoate solution on Ag film which was prepared by magnetron sputtering.Vibrational Spectra of dimethoate coating was studied by surface-enhanced Raman scattering（SERS）.The results showed that the failure of crystal structure makes the widening and blue shift of υ（P—S） and υ（P‖S） modes in dimethoate coating SERS system,hydrolysis causes the intensities of δ（SPOC） and δs（COPOC） decreasing,the adsorption of O,N（O‖C—N） and the protonated O on Ag film induces the increase of υ（O‖C—N）,υ（O‖C）,δ（N—H）,υ（CN）,δ（C—N—C）,δ（OPO） and υ（P—O） modes.The results could be used in the studies of dimethoate solution,and its residues in plants and food samples.关键词：dimethoate;Raman scattering;surface-enhanced Raman scattering;adsorption;hydrolysis
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发布时间： - 摘要：The molecularly imprinted polymers were synthesized with CH3Hg+ as a template,4-vinylpyridine as a functional monomer.8-Mercaptoquinoline was used as both a complex-forming agent and a fluorescence tag.The free-radical polymerization was performed within PVDF films and was initiated by 4,4′-azobisisobutyronitrile at 65 ℃ in dimethyl sulfoxide.The polymer showed a high selectivity for methylmercury ion.The optimum pH value was at 7.0.The detection limit for the method was up to 3.5×10-7mol/L.The polymer was applied in the determination of methylmercury ions in real water samples.The method showed a high selectivity against other metal ions and the recoveries for methylmercury ions were in the range of 93%-104%.关键词：methylmercury ion;8-mercaptoquinoline;molecular imprinting technology;fluorescence sensor
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发布时间： - 摘要：A solid phase extraction coupled with high performance liquid chromatography（SPE/HPLC） was developed for the determination of five antihistamines,e.g.doxylamine,tripelennamine,brompheniramine,diphenhydramine,chlorphenoxamine,in cosmetics.The samples were extracted with trichloroacetic acid solution under ultrasonication,and cleaned up with PCX solid phase extraction.The separation of five antihistamines was carried out on a C18 column using methanol-phosphate buffer as mobile phase.The calibration curves of five drugs were linear in the range of 5.0-100 mg/L,with correlation coefficients more than 0.999.The mean recoveries at spiked levels of 5.0,10.0,25.0 mg/kg were in the range of 92%-108% with RSDs（n=6）of 2.1%-4.2%.The limits of detection were in the range of 0.5-1.0 mg/L.The method was sensitive,reproducible and accurate.关键词：high performance liquid chromatography（HPLC）;solid phase extraction（SPE）;cosmetics;antihistamines;determination
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发布时间： - 摘要：A method for the determination of nine life elements（K,Ca,Ti,Mn,Fe,Ni,Cu,Zn and Rb） in pine pollen was developed by microwave digestion and total reflection X-ray fluorescence（TXRF）.The pollen was digested by microwave digestion.The counts,QXAS software and internal standard method were used for TXRF measurement.Effects of three sample preparation methods including dry ashing method，wet nitration method and microwave digestion method,on the TXRF results of certified reference material（GBW10026） were compared.The microwave digestion method was selected as the pretreatment method.Nine elements in GBW10026 were determined by TXRF with microwave digestion.The lower limit of detection（LLD） and the limit of determination （LDM） for different elements in pollen were calculated to be 0.002-0.054 mg/L and 0.004-0.122 mg/kg,respectively.The relative standard deviations（RSDs） were lower than 5.5%.This method showed advantages of easy operation,less sample consumption and low detection limit.The method was used to analyse the content of 9 elements in pine pollen,and there were was no significant difference between the results and those of ICP-MS.关键词：pine pollen;element analysis;microwave digestion;TXRF
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发布时间： - 摘要：A high performance liquid chromatographic（HPLC） method was established for the analysis of the total contents of maleic acid and maleic anhydride in starch products.A better extraction method was developed by using 5% ethanol as extraction solvent and ultrasonic extraction time of 10 min.The optimal chromatographic separation conditions were as the follows:separation column:Plastisil ODS C18 column（250 mm×4.6 mm，5 μm）;mobile phase:methanol-1‰ phosphoric acid（2∶98）;detection wavelength:214 nm;flow rate:1.0 mL/min;column temperature:30 ℃.The limit of quantitation for formaleic acid was 5.0 mg/kg,and the linear range were in the range of 0.25-100 mg/L with a correlation coefficient of 0.999 7.The average spiked recoveries were between 88% and 89% with RSDs（n=5） less than 2%.The method could satisfy the requirement for the determination of the total contents of maleic acid and maleic anhydride in actual sample.关键词：maleic acid;maleic anhydride;high performance liquid chromatography（HPLC）;starch products
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