最新刊期
卷 34 ， 期 8 ， 2015
- 摘要：A sensitive and selective liquid chromatography-positive mode electrospray ionization-tandem mass spectrometric (LC-MS/MS) method was developed for the determination of indoxacarb residue in 21 plant-derived foods,such as maize,peanut,walnut,soybean oil,green tea,grape,leek,mushroom and Chinese prickly ashy.The analyte in plant oil sample was extracted with n-hexane and acetonitrile,and the analyte in other kinds of samples was extracted by acetonitrile.Different types of samples were cleaned up by various methods.The extracts of grain,oil crops,nut and plant oil were cleaned up by gel permeation chromatography(GPC),the extract of tea was purified with solid phase extraction(SPE) column,the extracts of fruits,vegetables,edible fungus and spice were cleaned up with dispersive solid-phase extraction(dSPE) sorbents,namely primary secondary amine(PSA),octadecylsilane(C18) and graphitized carbon black(GCB).Then indoxacarb in the extract was separated on a reversed phase C18 column using an isocratic elution program of 0.1% formic acid-acetonitrile(30∶70).Qualitative analysis was performed by electrospray ionization in positive mode(ESI+) under multiple reaction monitoring(MRM) mode.The matrix-matched calibrations were used to quantify the residue concentrations.The calibration curves showed good linearities in the certain concentration range for different matrices,with correlation coefficients(r2) more than 0.993.The average recoveries of indoxacarb in different matrices were in the range of 73.7%-115.2% at three spiked concentration levels,and relative standard deviations(RSD,n=5) were not more than 13.1%.The limits of quantitation(LOQ) were 1.5-9.5 μg/kg in different matrices.The method is versatile,sensitive and accurate,and could meet the detection requirements of indoxacarb residue in plant-derived foods.关键词：indoxacarb;liquid chromatography tandem mass spectrometry(LC-MS/MS);plant derived foods
- 2090
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- 1125
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- 5
发布时间： - 摘要：An analytical method was developed for the simultaneous determination of carbofuran,atrazine,carbaryl and 6 kinds of phthalate esters(PAEs) in environmental water by ultra performance liquid chromatography coupled with tandem quadrupole mass spectrometry(UPLC-MS /MS).The samples were extracted and purified with Pak C18 solid extraction phase(SPE) cartridge.The targeted compounds were separated on BEH C18 column with methanol water solution as mobile phase ,determined under multiple reactions monitoring(MRM) mode and quantified by the external standard method.Under the optimized condition,the calibration curves were linear in the range of 0.5-20.0 μg/L with correlation coefficients larger than 0.998.The limits of detection(LOD) and the limits of quantitation(LOQ) of the method were in the ranges of 0.05-0.12 μg/L and 0.2-0.3 μg/L,respectively.The recoveries were between 86.0% and 96.5%,with RSDs(n=6) less than 5%.This method was sensitive,accurate and reliable, and was suitable for the determination of carbofuran,atrazine,carbaryl and 6 kinds of phthalate esters(PAEs) in environmental water.关键词：carbofuran;atrazine;carbaryl;phthalate-esters(PAEs);UPLC-MS/MS;environmental water
- 1990
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- 1176
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- 5
发布时间： - 摘要：Illegal drugs added in the process of livestock production would seriously affect the food safety in our country.The residues of 3 β2-agonists（e.g.，clenbuterol，salbutamol and ractopamine）in animal urine were prepared with deuterated isotope internal standard QuEChERS method ,and analyzed by gas chromatography-mass spectrometry（GC-MS）.Samples were enzymaticed with β-glucuronidase，and extracted with ammoniation ethyl acetate，then cleansed with anhydrous MgSO4 and primary secondary amine（PSA）sorbent.After supernatant was dried and derivatized，the analysis of target compounds was performed with GC-MS.The results indicated that good linear relationships were obtained for three β2-agonists in the certain concentration with correlation coefficients -greater than 0.998.The average recoveries of 3 analytes at three spiked concentration levels ranged from 95.0% to 101.0%，with relative standard deviations（RSDs）of 2.5%-6.2%.The limits of detection（LOD） were in the range of 0.3-0.6 μg/L and the limits of quantitation（LOQ） were 1.0-2.0 μg/L.This method has the advantages of simplicity，rapidness，stable operation，high precision，and is suitable for the determination of three kinds of β2-agonists residues in animal urine.关键词：deuterated isotope internal standard;QuEChERS;β2-agonists;gas chromatography-mass spectrometry（GC-MS）;animal urine
- 2132
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- 1106
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- 2
发布时间： - 摘要：The thermo-gravimetric behaviors under different atmosphere and glass transmission temperature（Tg） of self-made hyperbranched polyurethane（HPU） and UV-curable hyperbranched polyurethane acrylate（HPUA） were analysised with thermogravimetric analyzer(TG) and differential scanning calorimeter(DSC).On this basis，the thermal decomposition mechanisms of HPU and HPUA were investigated with the combination of themogravimetric analyzer and Fourier transform infrared spectrometer（TG-FTIR）.The TG results demonstrated that HPU and HPUA had a simtlar thermal degration behavior，both presenting three thermal degration plateforms.Comparing the decomposition behaviors of two compounds under air and nitrogen，their decomposition behaviors were found to be similar，but the former was more quick.DSC analysis indicated that when adding HEA，the Tg of HPUA was obviously lower than that of HPU.TG-IR analysis demonstrated that，compared to that under nitrogen atmosphere，HPU and HPUA decomposed more rapidly and thoroughly under air.The thermal decomposition mechanism of HPU was degradations of alcohol，urethane bond and ureido bond，respectively，and the thermal decomposition mechanism of HPUA was decomposition of hydroxyethyl acrylate，urethane bonds and ureido bond，respectively.关键词：TG-FTIR;hyperbranched polyurethane acrylate;Tg;thermal decomposition mechanism
- 2089
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- 1101
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- 3
发布时间： - 摘要：A new carbon nanotubes and cupric hexacyanoferrate modified electrode（MWCNTs-CuHCF/GCE） was prepared by drop coating and electropolymerization.The properties of electrode surface were characterized by Nyquist plots.The electrochemical behaviors of α-N and β-N on MWCNTs-CuHCF/GCE was investigated by cyclic voltammetry（CV）.Influences of type of buffer solution，pH value，amount of MWCNTs,electropolymerization of CuHCF and scan rate were discussed.The results indicated that there were two obvious oxidation peaks of α-N and β-N appearing at 0.335 V and 0.505 V，respectively.The oxidation peaks of α-N and β-N were completely separated and the oxidation peak currents of both α-N and β-N were linear with scan rate（v） in the range of 40-220 mV/s，which showed that the electrode processes of α-N and β-N were controlled by adsorption.The electron number（n），proton number（m），adsorption capacity（Γ）and effect area（A）of the modified electrode were studied.Under the optimal conditions，the differential pulse voltammetry（DPV）with derviative technique was used to determine naphthol isomers quantitatively.Good linear relationships between peak currents and concentrations of α-N and β-N were observed in the range of 0.5-100 μmol/L（rα-N=0.992；rβ-N=0.996）.The proposed method was applied in the determination of α-N and β-N in water samples with spiked recoveries of 94.2%-105.7%and 90.2%-103.3%,respectively.关键词：naphthol isomers;carbon nanotubes;cupric hexacyanoferrate;electrochemical impedance spectroscopy;differential pulse voltammetry;derivative technique
- 1906
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- 1641
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- 0
发布时间： - 摘要：Two drugs L1 and L2 were prepared by Claisen-Schmidt condensation reaction of 3-pyridinecarboxaldehyde with cyclohexanone or N-methyl-4-piperidinone.They were characterized by FTIR,1H NMR and elemental analysis.Their antitumor activities against human neoplastic cell lines A549,HePG2,MCF-7,SGC-7901,OVCA-433 and their cytotoxicities for HUVEC cell lines by CCK-8 method were subsequently evaluated.Their half maximal inhibitory concentration IC50 values were lower than 10 μmol/L,but their cytotoxicities were markedly lower.In addition,cellular uptake of L2 by HePG2 cells and HUVEC lines was carried out by confocal fluorescence images.The result showed that fluorescent enhancement following the change of time and concentration,further demonstrated the increase of cellular uptake amount of L2 by HePG2 cells.But the result showed that fluorescent intensity uniformity following the change of time and concentration,further demonstrated the uniformity of cellular uptake amount of L2 by HUVEC cells.关键词：α,β-unsaturated ketone;piperidone;antitumor;cytotoxicity;confocal laser scanning microscopy;cellular uptake
- 2056
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- 1055
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- 3
发布时间： - 摘要：A simple，rapid and mild condition method was developed for the preparation of ZnO@SiO2 core-shell structures quantum dots and Ag@SiO2/ZnO@SiO2 nanocomposite.Particle sizes，UV-vis absorption and emission spectra were characterized by transmission electron microscopy（TEM），ultraviolet spectrometry（UV），fluorescence spectroscopy（FL），nanometer particle size analyzer and ZETA potentials techniques.The results showed that the particles sizes of ZnO@SiO2 core-shell structures quantum dots were 3-8 nm and could emit yellow green fluorescence under the excitation of UV-vis light.Their maximum absorption wavelength was 330 nm，and the maximum fluorescence emission wavelengths were located at 510 nm.Ag@SiO2/ZnO@SiO2 could enhance the fluorescent of ZnO@SiO2 core-shell quantum dot，but it didn-t - change the emission peak position of ZnO@SiO2 core-shell quantum dot.Otherwise，Ag@SiO2/ZnO@SiO2 greatly enhanced the fluorescent stability of ZnO@SiO2 core-shell quantum dots at room temperature.Based on different level quenching of hemoglobin and L-cysteine for quantum dots,a simple，rapid and sensitive detection method was established.Under the optimized conditions，the characteristic fluorescence intensity of Ag@SiO2/ZnO@SiO2 at 510 nm was linearly proportional to the concentration of L-cysteine and hemoglobin in ranges of 0.068-10.10 mg/L and 4.00×102-4.00×103 mg/L，respectively.The detection limits were 6.92×10-3 mg/L and 2.04 mg/L，respectively，and the correlation coefficients were 0.993 8 and 0.995 1,respectively.The relative standard deviations for 11 replicate detections of 3.37 mg/L L-cysteine and 2.00×103 mg/L hemoglobin were 1.3% and 2.5%，respectively.关键词：zinc oxide;nano silver;fluorescence;stability;analysis of test;hemoglobin;L-cysteine
- 1990
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- 1091
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- 2
发布时间： - 摘要：A new method was developed for the simultaneous determination of four nitroimidazoles，e.g.metronidazole(MNZ),ornidazole(ONZ),ronidazole(RNZ) and secnidazole(SNZ), in acne cosmetics by gas chromatography-mass spectrometry(GC-MS).The samples were firstly diluted with sodium carbonate solution and then extracted with ethyl acetate.The extract was subsequently concentrated and/or the fat in which was wiped off with n-hexane.Finally,four nitroimidazoles were derivatised using N,O-bis(trimethylsilyl)-acetamide as derivating agent,and separated on a DB-5 MS capillary chromatographic column(30 m × 0.25 mm × 0.25 μm).The target compounds were identified by GC-MS with retention time and ratio of the characteristic ions under selected ion monitoring(SIM) mode,and quantified by the internal standard method.The result indicated that 4 analytes had good linear relationships(r2≥0.998) in the concentrations of 0.10-5.0 mg/L.The detection limits of target compounds for this method(LODs,S/N=3) ranged from 0.05 mg/kg to 0.10 mg/kg.The recoveries of four nitroimidazoles at three spiked levels in acne cream and acne water samples were in the range of 85.6%-104%,with relative standard deviations(RSDs,n= 6) of 2.9%-6.5%.The real sample analysis showed that this accurate and precise method could be applied in the simultaneous determination of four nitroimidazoles in acne cosmetics.关键词：gas chromatography-mass spectrometry(GC-MS);acne cosmetics;nitroimidazoles
- 2264
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- 1134
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- 14
发布时间： - 摘要：An innovative analytical approach based on the use of comprehensive two-dimensional hydrophilic interaction/reversed phase liquid chromatography（HILIC/RPLC） was applied to obtain the profiling of phenolic compounds in Chuju.The method involved the use of a microbore hydrophilic interaction column containing a diol stationary phase（Lichrospher diol-5） in the first dimension combined with a reversed phase column（Cortecs C18+） in the second dimension，and applied two sample loops as interface between the first and the second dimension.Two different gradient elutions were employed in the two dimensions，respectively.Detecton wavelength was set at 330 nm,and sampling rate was 15 Hz in the diode array detection.The theoretical peak capacity was up to 1 117 while the surface coverage proposed by Gilar（SCG） was 0.56，indicating both good resolution and good orthogonality of this 2D-LC system.23 peaks in the 2D-LC separation space were found，and 13（apigenin，luteolin，acacetin，acacetin-7-O-glucoside，chlorogenic acid，isorhamnetin-3-O-glucoside，luteolin-7-O-glucoside，acacetin-7-O-rutinoside，acacetin-7-O-rutinoside，quercitrin，isochlorogenic acid A，isochlorogenic acid B，apioside）of them were allowed tentative identification according to comparing with retention times and maximum absorption wavelengths between the sample and standards.In which 4 phenolic compounds（isorhamnetin-3-O-glucoside，acacetin-7-O-rutinoside，eriodictyol-7-O-glucoside，apioside）were firstly found in Chuju and isorhamnetin-3-O-glucoside was firstly found in Dendranthema morifolium.关键词：Chuju;phenolic compounds;comprehensive two-dimensional liquid chromatography;hydrophilic interaction/reversed phase liquid chromatography（HILIC /RPLC）
- 2293
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- 1069
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- 2
发布时间： - 摘要：A simple and rapid method for the preconcentration and determination of seven naphthalenediols in water samples with vortex assisted dispersive liquid-liquid microextraction based on solidification of floating organic drop(VA-DLLME-SFO) and high performance liquid chromatography(HPLC) was established.The target compounds in water samples were synergistically extracted in vortex dispersed mode,with ethyl ether-dodecanol as binary micro-extraction agent,then separated on a C18 chromatographic column and determined by HPLC.The kind and dosage of extraction agent,extraction time,dosage of sodium chloride and other conditions were optimized.The optimum extraction conditions were as follows:extraction agent:100 μL ethyl ether-50 μL dodecanol,amount of sodium chloride:0.2 g/mL,vortex extraction time:3 min.Under the optimized conditions,the calibration curves of 7 naphthalenediols were linear in the certain concentration range with correlation coefficients greater than 0.997.The detection limits of the method(S/N=3) were between 1.7 μg/L and 6.0 μg/L.The average recoveries of naphthalenediols at three spiked levels in water sample ranged from 82.1% to 106.0% with relative standard deviations(RSD,n=5) of 1.2%-4.1%.The inter RSDs(n=5) ranged from 2.5% to 5.7% at the middle spiked level.The developed method was simple and environment-friendly,and the vortex-assisted dispersion could largely enhance the mass transfer rate and shorten the required extraction time.Therefore,the method was suitable for the detection of naphthalenediols in water samples.关键词：Vortex-assisted dispersive liquid-liquid microextraction based on solidification of floating organic drop(VA-DLLME-SFO);naphthalenediols;water sample;high performance liquid chromatography(HPLC)
- 2231
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- 1082
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- 5
发布时间： - 摘要：Fusarium graminearum was inoculated on rice medium and cultivated at 28 ℃ for 4 weeks in the dark.The medium was extracted with acetonitrile-water（84∶16），and then first cleaned up with home-made clean-up cartridges to remove pigment and tannin，followed by two steps of semi-preparative liquid chromatography for further purification.The target compound was separated on a Pursuit XRs C18（10 mm×250 mm，5 μm）column using methanol-water（30∶70）as mobile phase，and then purfied with a Semi-preparative SB-CN column（9.4 mm×250 mm，5 μm） using methanol-water（5∶95） as mobile phase.The obtained deoxyuni valenol(DON) was qualified by high performance liquid chromatography tandem mass spectrometry（HPLC-MS/MS） both in positive electrospray ionization mode（ESI+）and negative electrospray ionization mode（ESI-）.The precursor ions of the compound were 319.1［M+Na］+，297.1［M+H］+，355.2［M+CH3COO］-，341.2［M+HCOO］-，295.1［M-H］-，and the major product ions were 175，231，235，249，179，233，237，265，which indicated that the obtained substance was DON.The purity of the prepared DON was determined to be （99.18±0.11）% by the external standard method.Based on the above observations，it was easily concluded that the preparation method for DON was simple，efficient，stable and economical.关键词：deoxynivalenol（DON）;Fusarium graminearum;semi-preparative liquid chromatography;identification
- 2137
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- 1149
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- 2
发布时间： - 摘要：A reliable and simple method was developed for the determination of L-ascorbic acid，D-isoascorbic acid，dehydroascorbic acid and total vitamin C in fruit and vegetable by high performance liquid chromatography(HPLC).The fruit or vegetable sample were extracted with metaphosphoric acid.L-Ascorbic acid and D-isoascorbic acid in extract were directly determined by HPLC with ultraviolet spectrophotometric detection.Dehydroascorbic acid in extract was reduced to L-ascorbic acid by L-cysteine in trisodium phosphate(pH 7. 0-7.2) solution，and then total vitamin C was determined.The dehydroascorbic acid was calculated by substracting L-Vc from total vitamin C.The analytes were separated on a C18 column using methanol-0.01 mol/L phosphate buffer (pH 3.5) as mobile phase，and analyzed quantitatively at UV wavelength of 245 nm by the external standard method.The calibration curves for L-ascorbic acid and D-isoascorbic acid were linear in the range of 0.5-50 mg/L with correlation coefficients more than 0.999.The limits of detection were 42.0 μg/kg for L-ascorbic acid，19.4 μg/kg for D-isoascorbic acid and 262 μg/kg for dehydroascorbic acid.The average recoveries of three substances in four matrices ranged from 82.8% to 111.3% with relative standard deviations(RSD) less than 15% at three spiked levels.The method was simple，sensitive and accurate，and was suitable for the determination of L-ascorbic acid，D-isoascorbic acid，dehydroascorbic acid and total vitamin C in fruit and vegetable samples.关键词：HPLC;L-ascorbic acid;D-isoascorbic acid;dehydroascorbic acid;fruit;vegetable
- 2841
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- 1190
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- 7
发布时间： - 摘要：K+-CD-MOFs,a novel metal-organic frameworks,were prepared using green environment and biocompatible γ-cyclodextrin as ligand and potassium,and characterized by transmission electron microscopy,Fourier transform infrared spectroscopy and X ray diffraction.The electrochemical behavior of copper(Ⅱ) was investigated on a glassy carbon electrode modified with K+-CD-MOFs by cyclic voltammetry and differential pulse voltammetry,and various experimental factors including kind of buffer,pH value and scan rate,were optimizedUnder the conditions of pH 5.0 acetic acid buffer,scan range of-0.4-0.4 V and scan rate of 0.1 V/s,the peak currents varied linearly with the concentration of copper(Ⅱ) in the range of 0.1-91.7 mg/L,and the detection limit(S/N=3) was 0.018 mg/L.The results indicated that this original material exhibited good electrochemical activities.The effects of other co-existing cations including Ca2+,Zn2+,Mg2+,Pb2+,Cd2+ and Hg2+ were also studied on K+-CD-MOFs modified glassy carbon electrode,which showed that the obtained MOF had a high selectivity to copper ion,and the peak current can not be interfered significantly except for Hg2+.The electrochemical method displayed the advantages of high sensitivity,reproducibility,stability and certain anti-ions interference ability,and could be used to detect rapidly and exactly the copper(Ⅱ) in industrial waste water samples. It is also showed that the novel metal-organic frameworks fabricated electrochemical sensor has a huge potential in determination of heavy metals.关键词：cyclodextrin;metal-organic frameworks;cyclic voltammetry;differential pulse voltammetry;copper
- 2049
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- 1036
- |
- 5
发布时间： - 摘要：A gas chromatography-mass spectrometric method was developed for the simultaneous determination of three prohibited bactericides（chlorothalonil，myclobutanil and captafol） in anti-acne cosmetics.Lotion-type cosmetic samples were injected for analysis after extracted with methanol and dried with anhydrous sodium sulfate.Grease-type cosmetic samples such as emulsion and cream were first demulsificated with sodium chloride，then extracted with methanol and dried using anhydrous sodium sulfate.As a following clean up step，dispersive solid-phase extraction（DSPE） was utilized to minimize the interference of co-extracted substances.The chromatographic separation was performed on an HP-5MS（30 m×0.25 mm×0.25 μm） capillary column.The mass spectrometric analysis was conducted with electron ionization in selected ion monitoring（SIM） mode.The characteristic fragment ions were used for qualification,and the external standard method was employed for quantitation.Under the optimized conditions，this method showed a good linearity（r2≥0.997） in the appropriate concentration ranges.The limits of detection（LODs） for chlorothalonil，myclobutanil and captafol were 0.1，0.2,0.01 mg/kg，and the limits of quantitation（LOQs） were 0.2，0.5,0.02 mg/kg，respectively.The recoveries of three analytes ranged from 80.5% to 111.3%，with relative standard deviations（RSDs，n=6） of 1.8%-10.3%.The proposed method was validated with accuracy，reliability，simplicity and sensitivity，and could provide a scientific basis and technical support for the inspection and quality control of anti-acne cosmetics.关键词：dispersive solid-phase extraction(dSPE);gas chromatography-mass spectrometry（GC-MS）;prohibited bactericides;anti-acne cosmetics
- 2018
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- 1046
- |
- 1
发布时间： - 摘要：A capillary electrophoresis method was established for the chiral separation of venlafaxine enantiomers,with trimethyl-hydroxyeth bis(trifluoromethylsulfonyl) imide(HOEtN1,1,1NTf2) and carboxymethyl-β-cyclodextrin(CM-β-CD) as chiral selectors.Influences of CM-β-CD concentration,ionic liquid and buffer concentration,buffer pH value and separation voltage on chiral separation were investigated.The optimal enantioseparation conditions were as follows:background electrolyte(BGE)：20 mmol?L-1 Na2HPO4-H3PO4 buffer(pH 6.0) containing 30 mmol?L-1 HOEtN1,1,1NTf2 and 4.5 mmol?L-1 CM-β-CD,applied voltage:20 kV,detection wavelength:230 nm,sampling time:10 s.Under the optimal enantioseparation conditions,the baseline separation was achieved for venlafaxine enantiomers with resolution of 1.82 in 9 min.The method is of simple operation,fast analysis and good separation effect,which is proved to be suitable for the enantioseparation of venlafaxine.It could also provide a reference for the separation of other chiral drugs.关键词：ionic liquids;carboxymethyl-β-cyclodextrin(CM-β-CD);capillary electrophoresis;enantiomer separation;venlafaxine
- 2582
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- 1013
- |
- 1
发布时间： - 摘要：An electrochemical sensor based on multi-walled carbon nanotubes and poly-L-lysine film modified glassy carbon electrode,on which multi-walled carbon nanotubes were drop-coated and poly-L-lysine film was prepared by electropolymerization,was fabricated.And a novel electrochemical method was established for the determination of lead ion by using anodic stripping voltammetry.Electrochemical behaviors of lead ions on multi-walled carbon nanotubes/poly-L-lysine modified glassy carbon electrode were studied with linear scan voltammetry and cyclic voltammetry techniques.Determination of lead ions was conducted under the optimal experimental conditions such as choices of supporting electrolyte,pH value of the solution,amount of poly-L-lysine,deposition time and deposition potential.Results indicated that a good linear relationship between anodic stripping peak current and concentration of lead ions was observed in the range of 2.0×10-7-8.0×10-5 mol?L-1 with a detection limit of 1.0×10-7 mol?L-1.A recovery experiment on rice sample was conducted by using as prepared modified electrode,and recoveries were in the range of 98%-102%.With good sensitivity and stability,the method was successfully applied in the determination of lead ions in rice sample.关键词：multi-walled carbon nanotube;poly-L-lysine;modified electrode;lead ion;anodic stripping voltammetry
- 2004
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- 1097
- |
- 6
发布时间： - 摘要：Under alkaline condition, gold nanoparticles(AuNPs) could enhance the chemiluminesence(CL) of luminol-silver nitrate system,and amitriptyline hydrochloride could greatly enhance CL signals. Based on this,a new simple CL method was developed to detect the content of amitriptyline hydrochloride.The experimental conditions were optimized,and the possible mechanism of the system was discussed.Under the optimal conditions,the relative CL intensity was linearly proportional to amitriptyline hydrochloride concentration in the range of 3.0×10-9-3.0×10-7 g/mL,with a correlation coefficient of 0.999 4 and a detection limit(S/N=3) of 2.1×10-9 g/mL.The RSD (n=11) was 2.0% for 5.0×10-8 g/mL amitriptyline hydrochloride.The method was applied in the determination of amitriptyline hydrochloride tablets,and the result was in consistent with the standard method.关键词：amitriptyline hydrochloride;gold nanoparticles;luminol;chemiluminesence
- 1909
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- 1107
- |
- 1
发布时间： - 摘要：A polydopamine(PDA) modified glassy carbon electrode(GCE) was fabricated by self-polymerization of dopamine(DA) and was used to detect the trace lead in iodized salt,pure water and tap water.The experiment conditions of self-polymerization of DA and square wave stripping voltammetry were optimized.The optimal conditions were as follows:self-polymerization solution:Tris-HCl(0.01 mol/L,pH 8.5) containing 2 mg/mL DA;self-polymerization time:2.5 h;reaction medium of lead:0.1 mol/L HCl solution;accumulation potential:-1.0 V;accumulation time:300 s. The type of dissolution peak is good and the peak current is high under the optimal conditions.The peak current is proportional to concentration of lead in the ranges of 0.1-1.0 μg/L and 1.0-10.0 μg/L,with a detection limit of 0.016 5 μg/L.The results showed that the new method introduced is simple,sensitive and low cost,and could be applied in the determination of trace lead in iodized salt,pure water and tap water.关键词：polydopamine;modified electrode;square wave stripping voltammetry;trace lead
- 1985
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- 996
- |
- 1
发布时间： - 摘要：Electrochemical behavior of the anticancer doxorubicin hydrochloride（DOX）and the interaction of DOX with human telomere DNA were investigated by cyclic voltammetry in aqueous medium using pH 6.0 PBS buffer.The results showed that a pair of reversible oxidation-reduction peaks were observed at -0.585 V and -0.638 V in pH 6.0 PBS buffer.There existed excellent linearities between oxidation peak current and concentration of DOX in the ranges of 0.03-0.8 μmol/L and 0.8-10 μmol/L by linear sweep voltammetric method.Detection limit（S/N=3） was 0.01 μmol/L.The relative standard deviations of the oxidation peak current obtained from 11 determinations of the same solutions containing 0.5 μmol/L DOX were 3.5%.The oxidation peak current of DOX gradually decreased with the adding of various concentrations of human telomere DNA，due to interaction of DOX with human telomere DNA.The binding ratio was calculated to be 1∶1 and the binding equilibrium constant was 1.11×103 L/mol.关键词：electrochemistry;doxorubicin hydrochloride;human telomere DNA;interaction;UV-Vis spectrometry
- 1985
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- 1001
- |
- 1
发布时间： - 摘要：Carbon dots（CDs） comprise a recently discovered class of strongly fluorescent，non-toxic，emission color tuning，non-blinking nanoparticles with great analytical and bioanalytical potential.In the past decade，the procedures for preparing C-dots have become increasingly versatile and facile，and their applications are being extended to a growing number of fields of biochemical sensing，environmental testing and so on.In this article，the progress made in the field of carbon dots in recent years，especially in latest developments of analytical and bioanalytical applications is reviewed，and the synthesis and properties of carbon dots are outlined.Finally，this review also provides perspectives on future opportunities and the remaining challenges confronting this research field.关键词：carbon dots;fluorescent;analysis;review
- 2304
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- 1658
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- 11
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