最新刊期
卷 35 ， 期 7 ， 2016
- 摘要：A new and sensitive analytical method was developed for the simultaneous determination of eighteen carbamate pesticides in biological samples by on-line solid phase extraction(on-line SPE) coupled with liquid chromatography-linear ion trap mass spectrometry(LC-LIT/MS).The samples were treated with acetonitrile,followed by dilution and centrifugation.The resulting solution was injected into LC system directly and processed with an Waters Oasis? HLB On-line SPE column for enrichment and purification.Separation was performed on a BETASIL C18 column with mixed mobile phases of methanol and water(both containing 0.1% formic acid) by gradient elution.The analytes were detected in selected reaction monitoring(SRM) or consecutive reaction monitoring(CRM) mode through positive electrospray ionization(ESI+).The calibration curves were linear within the investigated mass concentration ranges of the analytes(weighted 1/X),with correlation coefficients(r2) of 0.9943-0.9994.The LODs were in the ranges of 0.1-5ng/mL for whole blood and urine,and 0.1-5ng/g for liver tissue.The recoveries at three spiked levels ranged from 90.2% to 114.5%,with RSDs(n=4) of 0.5%-7.5%.The developed method is simple and accurate,and is sensitive for the rapid determination of eighteen carbamate pesticides in biological samples.关键词：on-line solid phase extraction(on-line SPE);liquid chromatography-linear ion trap mass spectrometry(LC-LIT/MS);consecutive reaction monitoring(CRM);carbamate pesticides;biological samples
- 2144
- |
- 3
- |
- 6
发布时间： - 摘要：An analytical method for the qualitative analysis of lipids in different parts of Pelteoobagrus fulvidraco was developed by ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry(UPLC-Q-TOF-MS/MS).The dried tissue and serum were extracted with methanol-chloroform(1∶1).The separation of extract was performed on a C8 analytical column(100mm×2.1mm,1.7μm),using methanol-acetonitrile-isopropanol(1∶1∶1)(A) and acetonitrile-water(B) as mobile phases.Both A and B contained 0.1% formic acid and 0.01%sodium formate.The analysis of lipids was performed in positive and negative ionization modes.Under the optimized condition,mass-to-charge values of each lipid were obtained by high-resolution mass spectrometry,and the elemental composition could be evaluated.Based on the fragmentation pathways and characteristic fragment ions of lipids,totally 85 lipids were identified in serum,muscle and liver,which contain ten classes: phosphatidylcholines(PC),lysophosphatidylcholines(Lyso-PC),phosphatidylethanolamine(PE),lysophosphatidylethanolamine(Lyso-PE),phosphatidylinositol(PI),phosphatidylserine(PS),diradylglycerols(DAG),triradylglycerols(TAG),sphingomyelin(SM) and ceramides(Cer).There were 19 lipids,including Lyso-PC 16∶0,nine PCs,three PIs,four TAGs and two SMs found in muscle,liver and serum.While PS and Lyso-PE were only observed in muscle,such as PS 18∶0/22∶6,Lyso-PE 16∶0 and Lyso-PE 18∶1.Ceramides was identified in the extracts of liver tissue.PE and DAG were identified in the muscle and liver tissue.The method was demonstrated to be simple,sensitive and rapid,and was suitable for the analysis of lipid in different parts of Pelteoobagrus fulvidraco.关键词：Pelteoobagrus fulvidraco;ultra-performance liquid chromatography coupled with mass spectrometry(UPLC-MS);lipids
- 1743
- |
- 1028
- |
- 1
发布时间： - 摘要：An HPLC-MS/MS methord was developed for the simultaneous determination of 14 forbidden colorants,including metanil yellow,acid violet 49,solvent red 49,solvent blue 35,tetramethylpararosaniline chloride（TMPC）,pentamethyltriphenylmethane（PMTPE）,hexamethylenepara rosaniline chloride（HMPC）,pigment orange 5,pigment red 53,sudan I,sudanⅡ,Sudan Ⅳ,rhodamine B,disperse yellow 3,in cosmetics.Cosmetic samples were extracted and dispersed with tetrahydrofuran,and some matrixes were precipitated out after addition of ammonium acetate solution and methanol.After centrifuged and filtered，the extract was separated on an Agilent poroshell 120 EC-C18 column（2.7 μm，3.0 mm×50 mm）by gradient elution with 10 mmol/L ammonium acetate-acetonitrile as mobile phase.The quantitative analysis was performed by the standard curve method of peak area.The linear ranges of 14 analytes were in the range of 0.01-1.0 μg/mL,with correlation coefficients more than 0.999.The limits of quantitation（LOQs）were in the range of 0.05-0.5 μg/g.The average recoveries at three spiked levels ranged from 85.4% to 106.3% with RSDs less than 10%.This method is accurate,simple,sensitive and reliable,and could be used for the analysis of 14 forbidden colorants in cosmetics.关键词：cosmetics;forbidden colorants;HPLC-MS/MS
- 1815
- |
- 1024
- |
- 2
发布时间： - 摘要：A high performance liquid chromatographic(HPLC) method was developed for the determination of coumarin allergen and its seven derivatives,including dihydrocoumarin,7 methoxycoumarin,7 methylcoumarin,7 ethoxy 4 methylcoumarin,cyclocoumarol,dicoumarol and acenocoumarol in cosmetics.Cosmetic samples were ultrasonically extracted with 0.1 mol/L aqueous sodium hydroxide-acetonitrile(1∶9).The extract was centrifuged,and filtered by microporous membrane.The chromatographic separation for the analytes was achieved on a ZORBAX SB-C18(250 mm×4.6 mm,5 μm) column.Gradient elution was performed using 0.05 mol/L aqueous ammonium acetate solution(containing 0.25% acetic acid) and acetonitrile.The quantification was carried out by the external standard method,and the suspected samples were further verified by high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS).The experimental results indicated that good linearities were observed over a certain concentration range with correlation coefficients better than 0.999 6,and the limits of quantitation(LOQs) were between 8 and 20 mg/kg.The average recoveries for the analytes at three spiked levels ranged from 84.6% to 100.7% with relative standard deviations(RSDs) of 0.8%-9.7%.The proposed method is accurate,robust and specific,and could provide scientific basis and a technical support for the inspection and quality control of cosmetics.关键词：coumarin and its derivatives;allergen;high performance liquid chromatography(HPLC);high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS);cosmetics
- 1948
- |
- 1034
- |
- 4
发布时间： - 摘要：Based on on line purification-enrichment technology，a novel method was developed for the determination of 15 polycyclic aromatic hydrocarbons in smoked fish and smoked meat by online solid phase extraction and high performance liquid chromatography with ultraviolet/fluorescence detection(online-SPE/HPLC-UV/FL-D).Experimental parameters such as extraction solvent and mobile phase were optimized.The homogenized smoked samples were dissolved with acetonitrile-acetone(6∶4),and then extracted ultrasonically.The online purification-enrichment was performed on a solid phase extraction ChromSpher Pi column(80 mm×3 mm),and the separation was carried out on a C18 reversed phase PAH column(250 mm×46 mm i.d.，5 μm) using ultraviolet detection at 220 nm and fluorescence detection.Isopropyl alcohol，acetonitrile and water were served as mobile phases by gradient elution.The results showed that good linearities for 15 polycyclic aromatic hydrocarbons existd in corresponding concentration ranges with correlation coefficients(r2) more than 0.999.The limits of detection(LODs) were between 0.03 μg/kg and 8.33 μg/kg.The recoveries of 15 components at three spiked levels in smoked fish samples were in the range of 67.4%-107.2% with relative standard deviations(RSD，n=6) of 0.2%-7.7%.The recoveries of 15 components at three spiked levels in smoked meat samples were in the range of 71.8%-110.5% with relative standard deviations(RSD，n=6) of 0.8%-8.9%.Verified by FAPAS quality control samples,the types and concentration ranges of analytes could meet the requirements.关键词：online solid phase extraction(online SPE);polycyclic aromatic hydrocarbons(PAHs);high performance liquid chromatography(HPLC);smoked fish;smoked meat
- 1854
- |
- 972
- |
- 6
发布时间： - 摘要：A method for preparing and certifying the reference materials of toltrazuil and toltrazuil sulfone in chicken muscle lyophilisates was presented.Toltrazuil was accessed to chicken by oral administration.With the metabolism of toltrazuil in chiken,a certain concentration of toltrazuil and toltrazuil sulfone were obtained in the muscles.Lyophilization of the muscles was performed in one batch,and 852 bags of samples were obtained by the procedure of homogenation，cryodesiccation and vacuum-packaging.The homogeneity and stability of the sample were examined by high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS).The value of the chemical constituent of the sample was certified through the collaborative analysis program participated by 8 laboratories,and the uncertainty was evaluated.The standard values of standard samples were certified as(60.42±9.12)μg/kg for toltrazuil and (73.10±12.48)μg/kg for toltrazuil sulfone.The results showed that good homogeneity and stability of the sample reached up to 24 months,and could be used for the quality control of toltrazuil and toltrazuil sulfone residue in chicken.关键词：reference materials;chicken;toltrazuil;toltrazuil sulfone;preparation;certification;high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)
- 1803
- |
- 980
- |
- 1
发布时间： - 摘要：A simple and novel electrochemical method was presented for the detection of bisphenol A(BPA) using spherical silica and gold nanoparticles composite film modified glass carbon electrode(SiO2/Au/GCE).The morphology and structure of SiO2 and SiO2/Au were characterized by scanning electron microscopy(SEM) and Fourier infrared spectrometry(FT-IR).Electrochemical impedance spectroscopy(EIS) and cyclic voltammetry(CV) were used to investigate the surface electrochemical property of SiO2/Au/GCE.The electrochemical behavior of BPA on SiO2/Au/GCE was studied by CV,chronocoulometry(CC),bulk electrolysis with coulometry,linear sweep voltammetry(LSV) and differential pulse voltammetry(DPV).The experimental parameters such as the thickness of film,accumulation time,pH value and scan rate were optimized,and some kinetic parameters were obtained.The results demonstrated that BPA had a good electrocatalytic activity on SiO2/Au/GCE,and the oxidation peak current at the modified electrode was 3 times as high as that at GCE.The electrooxidation of BPA on SiO2/Au/GCE was adsorption controlled,and was totally an irreversible electrode process accompanied by a two electron and two proton electrode reaction.Under the optimal conditions,the oxidation peak current for BPA was linear in the concentration ranges of 0.01-0.50 μmol/L and 0.50-25 μmol/L with a detection limit(S/N=3) of 1.9×10-8 mol/L.The proposed method was successfully applied in the determination of BPA in disposable glove with recoveries of 98.9%-105.3%.The results were consistent with those obtained by high performance liquid chromatography(HPLC).关键词：spherical silica and gold nanoparticles composite film;glass carbon electrode;bisphenol A(BPA);electrochemical behavior
- 1841
- |
- 943
- |
- 1
发布时间： - 摘要：The pyrolysis behavior of 3-pyridine formic acid anisalcohol ester was analyzed by on-line pyrolysis/gas chromatography-mass spectrometry（Py/GC-MS）.Firstly,target compound 3-pyridine formic acid anisalcohol ester was synthesized by acyl chlorination and esterification.The structure of the target compound was confirmed by 1H NMR,13C NMR,IR and HRMS,and its stability was studied by the method of TG-DTG-DSC.In air atmosphere,target compound was pyrolyzed at 300,600,900 ℃,respectively.The pyrolysis products were analyzed by GC-MS qualitatively and semi quantitatively.The result showed that the target compound experienced two mass loss.The first mass loss occurred between 129.9 ℃ and 158.9 ℃,and the mass loss was 2.3%.The second mass loss was between 158.9 ℃ and 274.9 ℃,the mass loss reached up to 901%,and the mass loss rate peaked at 230.1 ℃.44 kinds of compounds were detected,including flavor characteristic compounds such as 4-methoxy-benzaldehyde,4-methyl-phenol,alpha-terpineol,1-methoxy-4-methyl-benzene and methoxy-benzene.The result also indicated that pyrolysis temperature had significant effects on the type and relative content of pyrolysis products.The relative content of α calacorene was the highest at 300 ℃,and the highest contents of 4-methoxy benzaldehyde and 4-methyl-phenol were at 600 ℃ and 900 ℃,respectively.With the increase of pyrolysis temperature,the relative contents of benzaldehyde, methoxy benzene and 1-methoxy-4-methyl-benzene increased at first and then decreased,and the content of 4-methyl-phenol increased.According to the relative contents of pyrolysis products and their changes,the pyrolysis mechanism of target compound was preliminarily dicussed.关键词：gas chromatography-mass spectrometry（GC-MS）;pyrolysis;3-pyridine formic acid anisalcohol ester
- 2099
- |
- 1045
- |
- 1
发布时间： - 摘要：The desirable self-enhanced ECL luminophore was achieved by combining the coreactant of L-arginine(L-Arg) and the luminophor of tris(4,40-dicarboxylicacid-2,20-bipyridyl) ruthenium(Ⅱ) dichloride(Ru(dcbpy)2+3) to form a novel Ru(Ⅱ) complex,combing with an excellent conductivity property and large surface areas of the Au nanocages(AuNCs),an alternative for ultrasensitive detection of α fetoprotein(AFP) was designed utilizing the self enhanced electrochemiluminescence(ECL) of a novel Ru(Ⅱ) complex.For this proposed immunosensor,thiolated carbon nanotubes which were dispersed in Nafion solution were modified on the bare glass carbon electrode.Subsequently,hollow gold nanospheres(HGNPs) were assembled onto the modified electrode by Au-S bond,which could further improve the ECL intensity and be favorable for the adsorption of antibody.The measurement was based on a sandwich immunoassay method.The experimental results demonstrated that the proposed immunosensor exhibited a sensitive and stable response for the detection of AFP.The calibration curve was linear in the range of 1.0×10-5-1.0×10-3 ng/mL,with a limit of detection(S/N=3) of 3.3 fg/mL.关键词：self-enhanced;immunosensor;α-fetoprotein;Au nanocages;hollow gold nanospheres
- 1856
- |
- 959
- |
- 3
发布时间： - 摘要：A method was established for the determination of 16 kinds of herbicides in seawater by gas chromatography-mass spectrometry(GC-MS).The samples were concentrated,purified and eluted on an HLB solid phase extraction cartridge,and the elutions were evaporated to near dryness by nitrogen blow.Then the analytes were dissolved with ethyl acetate,determined by GC-MS in selected ion monitoring mode and quantified by the external standard method.The experimental results showed that good linearities for cynazine and pendimethalin existed in the range of 4.0-200 μg/L with their detection limits of 10.0 ng/L.The other 14 herbicides showed good linearities in the range of 2.0-100 μg/L,and their detection limits were all 5.0 ng/L.The average recoveries ranged from 78.3% to 115.0% with relative standard deviations of 4.4%-9.9%.The method is simple and accurate,and is specially suitable for the detection of 16 kinds of herbicides in seawater.关键词：herbicides;seawater;gas chromatography-mass spectrometry(GC-MS);solid phase extraction(SPE)
- 1707
- |
- 1171
- |
- 3
发布时间： - 摘要：A sensitive method based on ionic liquid dispersive liquid-liquid microextraction(IL-DLLME) and high performance liquid chromatography with diode array detector(HPLC-PDA) was developed for the preconcentration and determination of seven naphthalenediols in environmental water samples.The ionic liquid,1 butyl 3 methylimidazolium hexafluorophosphate(［C4MIM］［PF6］) was used as extraction agent,and 8.0 mL of aqueous phase was selected.Some important factors affecting the extraction efficiency such as amount of ［C4MIM］［PF6］,pH value of aqueous phase,extraction time and salt concentration were optimized.The optimized conditions were as follows:150 μL［C4MIM］［PF6］,pH value of aqueous solution：5.0-7.0,vortex extraction time：3 min, sodium chloride：0.20 g/mL.Under the optimized conditions,the calibration curves of 7 naphthalenediols were linear in the certain concentration range with correlation coefficients not less than 0.997 7.The enrichment factor of this method was 57,and the detection limits of this method(S/N=3) were between 0.3 μg/L and 1.0 μg/L.The average recoveries of naphthalenediols at three spiked levels in negative environmental water sample ranged from 83.5% to 103% with relative standard deviations(RSD,n=6) of 1.1%-3.8%.The developed method is rapid,sensitive and environment friendly,and is suitable for the detection of trace naphthalenediols in environmental water samples.关键词：ionic liquid dispersive liquid-liquid microextraction(IL-DLLME);high performance liquid chromatography(HPLC);naphthalenediol;environmental water sample
- 2137
- |
- 1089
- |
- 6
发布时间： - 摘要：Polydopamine(PDA) film was modified on the surface of glassy carbon electrode(GCE) by the self polymerization of dopamine(DA).Then the overoxidized polydopamine film modified electrode(OPDA/GCE) was obtained by electrochemical treatment of PDA film in alkaline solution.Furthermore,the chloramphenicol(CAP) concentration was obtained by using square wave voltammetry to detect directly the reduction current of CAP on OPDA/GCE.Self polymerization time of DA,electrochemical response of CAP on OPDA/GCE,electrochemical test condition,and influence and removal methods of dissolved oxygen,etc. were investigated and optimized.The results indicated that the reduction peak current of CAP on OPDA/GCE showed a good linear relationship in the contentraiton range of 3.0×10-6-1.1×10-3 mol/L,and the detection limit was 7.8×10-7 mol/L based on the signal to noise ratio of 3.The recoveries for milk and honey samples were in the ranges of 83.4%-94.1% and 91.5%-108.6%,respectively.The preparation method of the modified electrode is simple,inexpensive and convenient for batch preparation.The detection method of CAP is also simple and high-selective.关键词：polydopamine;overoxidized;self polymerization;modified electrode;chloramphenicol
- 1703
- |
- 1116
- |
- 2
发布时间： - 摘要：A rapid method for the determination of zanamivir residues chicken tissues was developed using QuEChERS approach coupled with ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).After ultrasonically extracted with(0.2 mol/L) hydrochloric acid-methanol(1∶9),the supernate was purified by QuEChERS method.The separation was performed on a NUCLEOSHELL- HILIC(3.0 mm×100 mm，2.7 μm) column by gradient elution using a mobile phase consisted of 5 mmol/L ammonium acetate(containing 0.2% formic acid) and acetonitrile.The identification of zanamivir was carried out by MS/MS in positive electrospray ionization(ESI+) and multiple reaction monitoring(MRM) mode，and the quantification was performed by the external standard calibration method.The results showed that the calibration curves were linear in the range of 5-100 ng/mL with correlation coefficients(r) greater than 0.990.The limits of quantitation(LOQs，S/N=10) of this method were 10.0 μg/kg for the chicken muscle and liver.The average recoveries of zanamivir at three spiked levels of 10，20，100 μg/kg were in the range of 80.5%-88.7% with relative standard deviations(RSDs，n=6) of 7.3%-11.8%.The method was applied in the determination of zanamivir residues in practical chickens.The developed method is simple，accurate，rapid，sensitive and efficient,and could be applied in the determination of zanamivir residues in chicken tissues.关键词：QuEChERS;ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS);zanamivir;residues;chicken tissues
- 1895
- |
- 971
- |
- 1
发布时间： - 摘要：A DART coupled with Orbitrap mass spectrometric method was developed for the qualitative and quantitative analyses of scutellaria radix.The component was identified by comparing with standard component and the report of relative researches as well as the full scan spectra and secondary spectra.In quantitative analysis,the Full MS-SIM and Targeted-MS2 mode was applied to obtain the mass spectrum,extract ion chromatography based on the parents ion and the product ion of baicalein(m/z 271.06→123.01) and wogonin(m/z 285.07→270.05) were used for quantitative analysis in the Targeted-MS2 mode.The signals of baicalein,wogonin,SkullcapflavonⅡ and other components were observed in the mass spectra of scutellaria radix.The linear ranges of baicalein and wogonin were 49.7-447.3 ng(r2=0.995) and 50.0-350 ng(r2=0.995),respectively.Their average recoveries were 87.0% and 66.0%,respectively.This method is suitable for the rapid analysis of scutellaria radix and other traditional Chinese herbal medicines.关键词：direct analysis in real time(DART);Orbitrap mass spectrometry;Scutellaria Radix;rapid analysis
- 1977
- |
- 931
- |
- 6
发布时间： - 摘要：A simple and rapid method was established for the determination of total iodine in different infant formulas by oven fast digestion with KOH solution combined with inductively coupled plasma mass spectrometry(ICP-MS).Concentration of KOH solution and temperature of digestion were optimized,and the stability of the digestion solution was investigated.The result indicated that the infant formula samples could be completely digested with 5% KOH solution in 1 h under 105 ℃,and the iodine ion could be stable for 48 h in the stabilizer of ammonia-Na2S2O3 solution.Using 141Pr as the internal standard,the iodine contents of the filtrate were determined by inductively coupled plasma mass spectrometry(ICP-MS).The method could reduce the complex sample processings such as pretreatment precipitation and derivative extraction compared with the national standard method(GB 5413.23-2010).Iodine presented favorable linearity in the range of 0-100 μg/L with correlation coefficient(r) of 1.000 0,and the method detection limit was 1.5 μg/kg.By means of determing the national standard material GBW 10017,NIST SRM 1849a and milk powders with different matrices,recoveries of 88.2%-107.4% were obtained and RSDs for repeatability and reproducibility were less than 5%.The iodine determined by the national standard material GBW 10017 and NIST SRM 1849a presented no significant differences between measured values and certified values.The method showed the advantages of sensitivity,accurancy and satisfactory recovery,and was suitable for the determination of total iodine in different infant formula matrices.关键词：KOH digestion;inductively coupled plasma mass spectrometry(ICP-MS);iodine;infant formula
- 1778
- |
- 971
- |
- 1
发布时间： - 摘要：A novel analysis method based on specific recognition of aptamer and fluorescence probe technique was established for the detection of total residues of tetracycline antibiotics(TCs)，including oxytetracycline,tetracycline,chlortetracycline and doxycycline etc.in aquaculture wastewater.Two segments of DNAs work together to identify TCs to fold into a stable “hairpin” double chain structure that can be inserted by nucleic acid dye DAPI to generate of fluorescence emission.Based on this,TCs can be quantified.Under the optimal experimental conditions,the working curve was established with oxytetracycline as target molecule,the fluorescence intensity showed a good linear relationship with concentration of oxytetracycline in the range of 10-50 nmol/L,and the detection limit of oxytetracycline was 2.3 nmol/L.When having oxytetracycline,tetracycline,chlortetracycline and doxycycline as additives,the average recoveries ranged from 88.5% to 102.3%,with relative standard deviations(n=5) of 3.2%-6.7%.The method is simple,sensitive and rapid,and could satisfy the requirements for determination of total TCs residues in the farm wastewater.关键词：aptamer;fluorescence analysis;tetracyclines;rapid detection;wastewater
- 2079
- |
- 973
- |
- 0
发布时间： - 摘要：Effects of the mixed additive containing tartaric acid and La3+ on the crystallization of calcium oxalate in silica gel were investigated by means of X-ray diffraction(XRD),Fourier transform infrared(FTIR) spectroscopy and scanning electron microscopy(SEM).The results indicated that artaric acid could inhibit the growth and aggregation of the crystal,and induce the formation of calcium oxalate dehydrate(COD).La3+ could also induce the COD formation and affect the morphology of calcium oxalate monohydrate(COM).While the mixed additive of tartaric acid and La3+ could not only enhance the ability of inducing the COD formation,but also inhibit the COM aggregation and decrease the COM surface area.The mixed additive of tartaric acid and La3+ is worthy to be considered for the prevention and treatment of urolithiasis.关键词：X-ray diffraction(XRD);Fourier transform infrared(FTIR) spectroscopy;scanning electron microscopy(SEM);La3+;calcium oxalate;tartaric acid;crystallization
- 1650
- |
- 922
- |
- 1
发布时间： - 摘要：A new HPLC method was developed for the determination of 16 carcinogenic polycyclic aromatic hydrocarbons(PAHs) which are monitored by the U.S.Environmental Protection Agency(EPA),in the extracts from coal tar pitch(CTP) with toluene.The separation of 16 analytes was performed on an Agilent PAHs chromatographic column,using acetonitrile-water with different ratios as mobile phase by gradient elution.The elute from the column was detected with ultraviolet detector.The linear range of the method was in the range of 0.5-20 mg/L,and the recoveries of 16 PAHs were in the range of 83.7%-98.9% with relative standard deviations(RSDs) less than 2%.The method was applied in the detection of 16 PAHs in two sources of CTPs .The results showed that the contents of 16 carcinogenic PAHs in two CTPs were 107.89 g/kg and 103.04 g/kg,and the benzo［a］pyrene contents in two CTPs were 11.86 g/kg and 13.85 g/kg,respectively.Experiments showed that this method could be applied in the determination of 16 carcinogenic PAHs in different kinds of CTPs with satisfactory results.关键词：high performance liquid chromatography(HPLC);coal tar pitch;polycyclic aromatic hydrocarbon;column chromatography
- 1818
- |
- 1007
- |
- 3
发布时间： - 摘要：A new kind of composite material(P-silica gel) was prepared by modifying porous silica gel with pectin extracted from the waste pomelo peel,and its adsorption properties to methylene blue(MB) in water sample were investigated by UV spectrophotometry.The composite material was characterized by Fourier transform infrared(FT-IR) spectroscopy.Effects of some factors such as silica gel before and after modification,amount of P-silica gel,pH value,adsorption time, temperature and actual water sample on adsorption of MB were investigated.The adsorption of porous silica gel to MB improved significantly after modified by pectin,and its adsorption capacity increased from 31.6 mg?g-1 to 41.7 mg?g-1.The adsorption capacity of P-silica gel increased with the increase of pH value and temperature,and it was conducive to adsorb MB with P-silica gel in alkaline condition.The maximum adsorption capacity of MB on P-silica gel was 59.2 mg?g-1 when using 5 mg P-silica gel at pH 7.0 and temperature of 50 ℃.Kinetic studies showed that the P-silica gel could adsorb MB rapidly and reached the equilibrium in 120 min.Furthermore,the adsorption behavior of MB on P-silica gel could be described by the pseudo second order kinetic model,which indicated that the process of P-silica gel adsorbing MB was mainly assigned to chemical adsorption.The adsorption isotherms data indicated that the Langmuir model was better than the Freundlich model.The removal rate of MB by P-silica gel could reach above 90% in the environmental water sample.关键词：pectin;silica gel;modify;methylene blue;adsorption;water sample
- 1686
- |
- 1025
- |
- 2
发布时间： - 摘要：An economic and facile preparation nonenzymatic uric acid sensor was successfully fabricated by electrodeposition of copper on SWNTs/Nafion modified glassy carbon electrode.The morphology of the material was observed by scanning electron microscopy(SEM)，and the element composition of the material was investigated by energy dispersive X-ray spectroscopy(EDX).Effects of various scan rates and pH conditions on the modified electrode were investigated.The linear range of detected UA was in the range of 0.1-1 000 μmol?L-1 and the limit of detection(LOD,S/N=3) was 0.058 5μmol?L-1.The sensor was applied in the detection of UA in human serum by the standard addition method with recoveries of 97.2%-103.9% and relative standard deviation(RSD)of 0.04%-0.11%.The results of the nonenzymatic method are highly consistent with that of the GOD-POD enzymatic method.The sensor shows the advantages of facile fabrication,high sensitivity,good stability and high reproducibility.关键词：single walled carbon nanotubes(SWNTs);uric-acid(UA);sensor;copper nanoparticles(CuNPs);Nafion
- 1705
- |
- 1099
- |
- 2
发布时间： - 摘要：A method for the rapid determination of clindamycin hydrochloride in clindamycin hydrochloride capsules by microchip capillary electrophoresis with contactless conductivity detection was developed.Influence parameters on the separation and detection such as type and concentration of buffer,type of additive,separation voltage and injection time were investigated.Under the optimal conditions,using 2.0 mmol?L-1 HAc-2.0 mmol?L-1 NaAc as buffer solution,clindamycin hydrochloride was separated and detected within 1.0 min at a separation voltage of 1.5 kV and an injection time of 15. 0 s.Clindamycin hydrochloride showed a good linear response in the range of 20.0-200.0 μg?mL-1,with a correlation coefficient（r） of 0.999 2.The limit of detection（S/N=3）was 5.0 μg?mL-1 with RSD of 21%,and the recoveries were in the range of 95.9%-103%.This method was simple and rapid,and could be used for the detection and quality control of clindamycin hydrochloride in clindamycin hydrochloride capsules.关键词：microfluidic chip;contactless conductivity detection;clindamycin hydrochloride capsules;clindamycin hydrochloride
- 1859
- |
- 985
- |
- 1
发布时间： - 摘要：Nitrogen doped porous carbon was used to immobilize acetylcholinesterase(AChE) to fabricate biosensor for the detection of organophosphorus pesticide phorate.The peak current was 0.195 8 μA at the AChE/GC electrode,while 0.841 4 μA was obtained at AChE/nitrogen doped porous carbon/GC electrode,indicating that nitrogen doped porous carbon can effectively immobilize AChE and enhance the sensitivity.The inhibition rate versus logarithm of phorate were linear in the range of 6.0×10-10-1.2×10-6 g/L,with a correlation coefficient(r2) of 0.998 5.The detection limit of phorate,calculated by inhibition rate of 10%,was 5.8×10-12 g/L.The sensor could be used for the detection of phorate in spinach juice with recoveries of 91.7%-97.4%.关键词：phorate;nitrogen doped porous carbon;acetylcholinesterase;acetylcholine
- 1735
- |
- 927
- |
- 1
发布时间： - 摘要：A headspace-gas chromatographic method was established for the determination of 10 kinds of benzene solvent residues in modified products.By optimizing the sample pretreatment and chromatographic conditions,the linear correlation coefficients of 10 analytes were more than 0.999,and the quantitation limits(S/N=10) were in the range of 0.924-1.044 mg/kg.The recoveries were in the range of 83.5%-118.5%,with relative standard deviations of 1.8%-8.2%.The method had the advantages of saving solvent,rapidness,good repeatability and easy operation.The experiment indicated that,under the condition of a certain temperature,correction fluid samples were volatilized a great deal of toluene，xylene，ethylbenzene and styrene,and a certain amount of 1,2,4-trimethylbenzene.Forthermore,the higher the temperature varied,the larger the volatile amount of benzene solvents was obtained.关键词：headspace-gas chromatography;modified products;benzene solvents
- 1660
- |
- 944
- |
- 4
发布时间： - 摘要：Nanomaterials,such as Fe2O3,CoO,MnO2 and ZnO,due to their unique properties,are widely applied in the development of electrochemical sensors.This article is focused on introducing the hydrothermal methods for preparation of nano transition metal oxides.The application progress of novel electrochemical sensors in food safety based on transition metal oxides is reviewed .关键词：electrochemical sensor;nanomaterials;hydrothermal;transition metal oxides;food safety
- 1854
- |
- 1059
- |
- 0
发布时间： - 摘要：Dispersive liquid-liquid microextraction(DLLME) is a novel sample preparation technique,which is based on the traditional liquid-liquid extraction.In the past few years,it has always grabbed the attention of researchers in the field of separation and analysis for the merit of utilization of μL level of extraction solvent,and it also shows a superior separation efficiency and a strong enrichment ability.In this paper,low toxic extractant solvents such like low density solvent,auxiliary solvent,back extraction solvent and ionic liquid,and the relevant microextraction mode,such as utilizing self made devices,solvent demulsification,solidification of a floating organic drop,uxiliary solvent extraction,back extraction and ionic liquid based DLLME were briefly reviewed according to the selection of extraction solvent.In the end,extraction characteristics of DLLME combined with other extraction techniques like liquid-liquid extraction,solid-phase extraction,solid-phase microextraction,dispersive solid-phase extraction,matrix solid phase dispersion extraction,super critical extraction,ultrasonic assisted extraction were also briefly reviewed.关键词：dispersive liquid-liquid microextraction;extraction solvent;review
- 1873
- |
- 1035
- |
- 12
发布时间： - 摘要：Amino acid is a fundamental material that organisms need,and its analysis is one of the most important technologies in life sciences.Owning the advantages of rapidness,easy operation,high detection sensitivity and wide application,the high performance liquid chromatography(HPLC) is widely used in many fields,such as food industry,pharmaceutical industry and life science research.In this article,the HPLC analytical methods of amino acids,including post column derivatization,pre column derivatization,high performance anion exchange chromatography with integrated pulsed amperometric detection and HPLC with evaporative light scattering detection,are reviewed.The characteristics of these methods are compared,which could provide a reference for the related research analysis.关键词：amino acids;high performance liquid chromatography(HPLC);pre column derivatization;post column derivatization;review;research progress
- 1797
- |
- 1027
- |
- 24
发布时间：
- Address：100 Xianlie Middle Road, Guangzhou Postal code：510070
- Tel：020-87684776,37656606 Fax：020-87684776 Email：fxcsxb@china.com
- Technical support is provided by Beijing Founder electronics co., LTD 粤ICP备12017312号-3
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0