最新刊期
卷 32 ， 期 2 ， 2013
- 摘要：An ultra-high performance liquid chromatography-tandem quadrupole mass spectrometric method was developed for the determination of monosaccharide composition and content in Mesona Chinensis Benth polysaccharides.Mesona Chinensis Benth Polysaccharides were extracted with hot water under alkaline environment,cleaned with C18 SPE cartridge,and then hydrolysised with trifluoroacetic acid at 110 ℃.The monosaccharaides were derivated with 1-phenyl-3-methyl-5-pyrazolone(PMP),and separated at a flow rate of 0.5 mL/min on a Waters ACQUITY UPLC BEH C18 column(2.1 mm i.d.×50 mm,1.7 μm) at 35 ℃,by using acetonitrile and 0.5 mmol/L ammonium acetate-0.05% acetic acid buffer as mobile phase by a gradient elution.The analysis of target compounds was performed in multiple reaction monitoring(MRM) mode via positive electrospray ionization,and quantified by the internal standard method.The developed method showed good linearities over the concentration range of 1-100 μmol/L for all monosaccharaides with correlation coefficient(r2) more than 0.96.The spiked recoveries were between 84% and 112%,and the relative standard deviations(RSD) were no more than 4.7%.The results showed that Mesona Chinensis Benth polysaccharides consisted of eight monosaccharides,including mannose,rhamnose,ribose,glucuronic-acid,galacturonic-acid,glucose,galactose,xylose,with the molar percentages of 7.4%,5.7%,4.2%,0.9%,28.4%,26.5%,16.4% and 10.6%,respectively.The method is simple,rapid,sensitive and convenient,and could be applied in the analysis of Mesona Chinensis Benth polysaccharides.关键词：Mesona Chinensis Benth polysaccharides;monosaccharide;precolumn derivatization;ultra-high performance liquid chromatography-tandem quadrupole mass spectrometry
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发布时间： - 摘要：A high performance liquid chromatography-tandem mass spectrometric（HPLC-MS/MS)method was developed for the determination of 8 kinds of mycotoxins（aflatoxin B1，aflatoxin B2,aflatoxin G1,aflatoxin G2，fumonisin B1，fumonisin B2，sterigmatocystin and roquefortine C) in cereal.The sample was diluted with hexane to remove the oil,then extracted with 60% acetonitrile.The acetonitrile layer was made up to constant volume and passed through the filter before tested.The detection was performed in the electrospray ion positive mode and multiple reaction monitoring（MRM) mode，and the quantitation of target compounds was carried out by the isotope dilution assays.The results indicated that the 8 compounds showed good linear relationships in certain concentration ranges,with correlation coefficients not less than than 0.997 0.The average recoveries ranged from 77% to 123%,with relative standard deviations of 0.6%-13.3%.The method was proved to be rapid and sensitive,and could be used for the detection of mycotoxins in cereal.关键词：isotope dilution assay;cereal;mycotoxins;high performance liquid chromatography-tandem mass spectrometry
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发布时间： - 摘要：A high performance capillary electrophoresis method for the simultaneous separatinon and determination of four anticoccidial drugs(e.g.sulfanilamide，sulfaclozine，sulfaquinoxaline，diclazuril) in soil was developed by using 0.1 mol/L NaOH and THF(3∶2) as extraction solution.The effects of some important factors such as pH value，composition and concentration of running buffer，separation voltage and separation temperature，were investigated,and the orthogonal test factors were optimized.The optimal conditions were as follows：the running buffer：50 mmol/L borax-200 mmol/L boric acid(pH 9.0),separation voltage：23 kV,separation temperature：25 ℃,UV detection wavelength：220 nm and 254 nm.Under the optimal chromatographic conditions，the four anticoccidial drugs can be well separated within 7.0 min.The calibration curves of four anticoccidial drugs were linear in the range of 1.56-50 mg/L with correlation coefficients(r2) of 0.994 7-0.999 9.The average recoveries of four anticoccidial drugs in soil sample at three spiked concentration levels of 2.0，5.0，10 mg/kg ranged from 77% to 90% ,with relative standard deviations(RSDs,n=6) of 6.3%-8.1%.The method was simple，rapid and low-cost,and was successfully applied in the determination of four anticoccidial drugs in the soil of poultry farms.关键词：high performance capillary electrophoresis;soil;anticoccidial drug;simultaneous separation and determination
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发布时间： - 摘要：A simple,rapid and sensitive method was developed for the simultaneous determination of vancomycin and norvancomycin in pork by ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).The sample was supersonically extracted with a mixture of 0.1% formic acid-acetonitrile(7∶3),and cleaned up with hexane(acetonitrile saturated) and a LC-C18 solid phase extraction cartridge.The separation of two targets was carried out on a Waters UPLC BEH C18 column by gradient elution with 0.1% formic acid-acetonitrile as mobile phase.With positive electrospray ionization(ESI+) and multiple reaction monitoring(MRM),the two compounds were identified with retention time and ion ratio.The results showed that the two compounds displayed excellent peak shapes within 3 min with correlation coefficients more than 0.99.The limits of detection(LOD,S/N=3) of vancomycin and norvancomycin were 0.5 μg/kg and 0.3 μg/kg,respectively.The average recoveries were between 80% and 88% for the target compounds at spiked levels of 1-20 μg/kg.The intra-day RSDs were no more than 13.4%,and the inter-day RSDs were no more than 12.5%.The method was accurate and sensitive,and was suitable for the quantitative and qualitative analyses of glycopeptide antibiotics in pork sample.关键词：vancomycin;norvancomycin;pork;ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)
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发布时间： - 摘要：A stable integrated gold film multi-electrode array,including six gold working electrodes(1 mm×2 mm),a gold counter electrode(2 mm×13 mm) and a thick-film Ag/AgCl reference electrode,was fabricated by mask technique of polyethylene sticky film and the gold sputtering technique on FR-4 glass fiber substrate.The electrochemical characteristics of the multi-electrode array fabricated were investigated using electrochemical methods.There was a negative shift of 0.067 V obtained on the thick-film Ag/AgCl reference electrode fabricated compared with a commercial Ag/AgCl/3.0 mol/L NaCl reference electrode.After one month,the potential of reference electrode did not change obviously.The surface roughness of the working electrodes was studied by scanning electrochemical microscope(SECM).The satisfied surface roughness was obtained.The reproducibility of electrochemical areas and properties of the gold working electrodes were evaluated by the cathodic peak areas in 0.10 mol/L H2SO4 aqueous solution and the Ipa/Ipc values in 5.0 mmol/L K3Fe(CN)6 aqueous solution,and satisfactory results were obtained.This work demonstrated that the multi-electrode array fabricated can be utilized as electrode system for following electrochemical studies.Multi-electrode array can be further applied as a basis electrode in the design and fabrication of electrochemical biosensor array.关键词：polyethylene adhesive masking;sputtering technology;multi-electrode array;electrochemical detection
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发布时间： - 摘要：The method and model for the separation of capsaicin-type alkaloids with ionic liquid(BmimBF4) as additives were established,and the separation mechanism was studied.The influence factors,including kind of ionic liquid,concentration of ionic liquid,length of alkyl groups in room temperature ionic liquids(RTILs) and column temperature were investigated.It was shown that the chromatographic behaviors of the analytes with a mobile phase containing ionic liquids of chaotropic anion were signally improved.The relationships between retention value and concentrations of different lengths of alkyl groups in ionic liquid preferably complied with the stoichiometric displacement model for retention(SDM-R),r＞0.99.It was clarified that the interactions between solutes and imidazole cations were almost completely competitive adsorption on the stationary phase.关键词：ionic liquids;capsaicin-type alkaloids;additive;SDM-R;HPLC
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发布时间： - 摘要：A comprehensive method was developed for the simultaneous analysis of 50 antibiotic drugs,including chloramphenicol,sulfonamides,fluoroquinolones,tetracyclines and macrolides in sewage sludge by ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）.The sludge samples were ultrasonically extracted with acetonitrile-water solution and then centrifugated.The supernatant were concentrated with an Oasis HLB solid-phase extraction（SPE） cartridge and purified with an amino SPE cartridge.The separation of 50 target drugs was performed on an ACQUITY UPLC BEH C18 column using a mobile phase of 0.1% formic acid-methanol（ESI+） or acetonitrile-water（ESI-）by gradient elution.A multiple reaction monitoring（MRM）was employed in mass spectrometry acquisition.The matrix matched external standard calibration was used for quantitation.Good linearities of the analytes were achieved over the concentration of 0.50-400 μg/L,with correlation coefficients above 0.99.The method quantitation limits（MQL）for target compounds were in the range of 0.10-5.00 μg/kg.Average recoveries of 50 analytes at three spiked levels ranged from 40% to 111% with relative standard deviations（RSDs）of 2.9%-27.1%.The developed method was applied in the analysis of target drugs in both activated and excess sludge samples from sewage treatment plants in Beijing,while 14 target compounds,namely sulfadiazine, sulfapyridine,sulfamethoxazole,pipemdilic acid,ofloxacin,enoxacin,pefloxacin,norfloxacin,ciprofloxacin,enrofloxacin,lomefloxacin,sparfloxacin,oxytetracycline and azithromycin,were detected in the concentration range of 1.2-442.5 μg/kg.The method was rapid,sensitive and reliable,and was suitable for the simultaneous determination of 50 antibiotics in sludge sample.关键词：sulfonamides;fluoroquinolones;tetracyclines;macrolides;chloramphenicol;UPLC-MS/MS;sludge
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发布时间： - 摘要：Under the simulated physiological conditions(at pH 7.4 and ionic strength of 0.15 mol?L-1),the interaction between kaempferide(KF) and bovine serum albumin(BSA) was assessed via fluorescence spectroscopy and ultra-violet absorption spectra under different temperatures,such as 298,304 and 310 K.The binding constant,number of binding sites and binding distance between KF and BSA were analyzed and contrasted by aid of the Tachiya model and Stern-Volmer equation,respectively.The result showed that,for Tachiya model,the binding constant and the binding distance increased with the increase of the temperature,the same as the change trend for Stern-Volmer equation.But the number of binding sites obtained by Tachiya model was much different from that by Stern-Volmer equation.The number of binding sites obtained by Stern-Volmer equation almost had no change with the temperature increasing；To the contrary,the number of binding sites obtained by Tachiya model had a great change with the temperature increasing.The result obtained by Tachiya model corresponds more closely to the practical conditions of interaction between small molecular and biological molecules than that by the Stern-Volmer equation.The thermodynamic parameters were calculated according to the vant Hoff equation.The enthalpy change ΔH,and the entropy change ΔS were found to be 179.87 kJ?mol-1 ,705.61 J?mol-1?K-1,respectively.The thermodynamic results suggest that hydrophobic force plays a major role in stabilizing KF-BSA complex.The effect of KF on the conformation of BSA was also studied by synchronous fluorescence spectra.It indicated that the binding of KF to BSA leads to changes in the conformation of BSA.The interaction between KF and BSA was realized through the combination of KF and tryptophan residue.关键词：kaempferide(KF);BSA;Tachiya model;Stern-Volmer equation;interaction
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发布时间： - 摘要：A new approach was established for the simultaneous determination of eight classes of limited using veterinary drug residues,including quinolones,macrolides,sulfoamides,trimethoprim,lincosamides,nitroimidazoles,quinoxalines and peptides,in aquatic products by high performance liquid chromatography-tandem mass spectrometry（HPLC-MS/MS）.The analytes were extracted with 1% acetic acid in acetonitrile,then purified with refrigerated centrifuge and hexane.The sample matrix-matched calibration was used to determine the residue contents by the external standard.Electrospray ionization mass spectrometry was operated in the positive mode using multiple reaction monitoring（MRM）for the qualitative and quantitative analyses of 38 analytes.The results indicated that correlation coefficients of the calibration curves were more than 0.99.The average recoveries of 38 analytes at four spiked concentration levels ranged from 43% to 123%.The intra-day relative standard deviations（RSDs） were in the range of 1.0%-26.4%,and the inter-day RSDs were 1.6%-28.9%.The limits of quantitation（LOQs,S/N≥10） were in the range of 5-20 μg/kg.The method is simple,rapid and reliable,and is suitable for the simultaneous determination of multiresidues of veterinary drugs in aquatic products.关键词：high performance liquid chromatography-tandem mass spectrometry;aquatic products;limited using veterinary drug;multiple residues;rapid screening
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发布时间： - 摘要：A high performance aqueous normal phase(ANP) chromatography-tandem mass spectrometric method was established for the simultaneous determination of glyphosate(GLY) and aminomethylphosphonic acid(AMPA) in plant-derived foodstuff.The sample was extracted with ultrapure grade water,and purified with anion-exchange column(MAX).The seperation of GLY and AMPA were carried out by ANP chromatography using 5 mmol/L ammonium acetate(A) and 5% water-95% acetonitrile ammonium acetate solution(B) as mobile phases.The detection of target compounds was performed by MS under electrospray ionization source,negative scanning mode and multiple reaction monitoring.The external standard method was used for the quantitative analysis.The result indicated that the linear ranges of GLY and AMPA were in the concentration ranges of 10-500 μg/L and 20-1 000 μg/L,respectively,with correlation coefficients more than 0.99.The limits of detection(LODs,S/N=3) of two compounds were both 0.01 mg/kg,and the limits of quantitation(LOQs,S/N=10) were 0.02 mg/kg for GLY and 0.04 mg/kg for AMPA,respetively.The recoveries of GLY and AMPA in six matries ranged from 78% to 113%,with relative standard deviations(RSDs) of 3.2-11.0%.The method could meet the requirements for daily food determination with its high sensitivity,recovery and selectivity.关键词：glyphosate;aminomethylphosphonic-acid;aqueous normal phase;liquid chromatography-tandem mass spectrometry;anion exchange column
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发布时间： - 摘要：A quantitative and qualitative method of ultra performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry(UPLC-MS/MS) was developed for the rapid and sensitive analysis of malachite green(MG) and its main metabolite leucomalachite green(LMG) in water and sediment sample.Water sample was extracted and cleaned up using mixed-mode cation exchange solid-phase extraction cartridges(MCX)，and sediment sample was supersonically extracted with acetonitrile-dichlorome mixture.Gradient UPLC separation was performed on a C18 column(BEH C18 1.7 μm,2.1 mm×50 mm) with acetonitrile(containing 0.1% formic acid) and 5 mmol/L ammonium acetate(containing 0.1% formic acid) as mobile phase.Mass spectrometric determination was carried out under an electrospray ionization interface(ESI) in positive ion mode and multiple reaction monitoring(MRM) mode.The calibration curves of two analytes were linear in the range of 0.2-100 μg/L with correlation coefficients not less than 0.995.The average recoveries of MG and LMG in blank water samples at three spiked concentration levels of 1.0,10.0,100 ng/L were in the range of 77%-90% with RSDs of 7.2%-11.4%,and its limit of detection(LOD) and limit of quantitation(LOQ)were 0.2 ng/L and 0.4 ng/L,respectively.The average recoveries of MG and LMG in sediment at three spiked levels of 0.20，2.00 and 20.0 μg/kg ranged from 82% to 91% with RSDs of 6.3%-11.6%,and its limit of detection(LOD) and limit of quantitation(LOQ)were 0.02 μg?kg-1 and 0.04 μg?kg-1,respectively.The method was suitable for the determination of MG and LMG residues in practically aquatic environmental water and sediment with high sensitivity and selectivity.关键词：UPLC-MS/MS;determination;water;sediment;malachite green(MG);leucomalachite green(LMG)
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发布时间： - 摘要：A high performance liquid chromatography tandem electrospray ionization mass spectrometry（HPLC-ESI MS/MS） method was developed and validated for the determination of phenolic endocrine disrupting chemicals（EDCs），including bisphenol A（BPA）,triclosan（TCS）,17α-ethynylestradiol（EE2）,estrone（E1） and 17 β-estradiol（E2）in human urine.The samples were purified by liquid-liquid extraction,derivertized with dansyl chloride,and detected by HPLC-ESI MS/MS.The target compounds were quantified by the stable isotope dilution technique.The calibration curve were linear in the range of 0.2-100 μg/L for the 5 EDCs with correlation coefficients more than 0.99.The limits of detection of 5 EDCs were in the range of 0.02-0.27 μg/L.The matrix recoveries of the method for 5 EDCs at three spiked levels of 5,10 and 50 μg/L ranged from 85% to 125%.The relative standard deviations（RSDs,n=3） were between 0.53% and 14.4%.The method was successfully applied in the analysis of 5 EDCs in human urine with its sensitivity and accurancy .关键词：HPLC-MS/MS;endocrine disrupting chemicals（EDCs）;urine
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发布时间： - 摘要：Ionic liquid-based ultrahigh pressure-assisted extraction(IL-UPE) combined with high performance liquid chromatography(HPLC) was applied in extracting arctiin and arctigenin in Fructus Arctii.The influences of experimental factors including ionic liquids with different cations and anions,ionic liquid concentration,extraction pressure,extraction time and ratio of solid to liquid,were investigated.The optimal conditions were as follows：extraction solvent：0.80 mol/L 1-lauryl-3-methylimidazolium bromide ionic liquid solution,extraction pressure：200 MPa,extraction time：2 min,solid/liquid ratio:1∶20(g/mL).Under the optimum conditions,the yields of arctiin and arctigenin are 37.15 mg/g and 8.04 mg/g,respectively.Compared with the conventional extraction methods(e.g. the ultrasonic assisted extraction(UAE) and the heat reflux extraction(HRE)),the IL-UPE method was rapid(extraction time：2 min),effective and also environment-friendly.关键词：ultrahigh pressure;ionic liquid;arctiin;arctigenin
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发布时间： - 摘要：A high performance liquid chromatographic method was developed for the determination of total acetoin in wine using 2-4-dinitrophenylhydrazine(DNPH) derivatization.The experimental conditions,including pH value,reaction time,DNPH content,reaction temperature and processing step after derivatization,were optimized.The derivatization products were separated on an Ultimate C18 column(4.6 mm×250 mm,5 μm) using acetonitrile-water(55∶45)as mobile phase at a flow rate of 1.0 mL/min.The oven temperature was set at 30 ℃,and the detection wavelength was 363 nm.Under the optimal conditions,the linear range for acetoin was in the range of 0-40.0 mg/L with correlation coefficient of 0.999 9.The spiked recoveries of acetoin in the dry red wine sample were in the range of 95%-106% with relative standard deviations(RSDs)of 2.3%-3.4%,and the spiked recoveries of the dry white wine samples were in the range of 94%-104% with RSDs of 2.5%-3.1%.The contents of acetoin in some different types of wine samples were tested,and the results showed that the concentrations of total acetoin in domestic fake and shoddy wine samples were much higher than those in good quality wine samples.Besides,the concentration of total acetoin in home-brewed wine samples from badgrapes were also higher.Therefore,the concentration of total acetoin can provide a reference for the wine quality identification.关键词：acetoin;dinitrophenylhydrazine;derivatization;high performance liquid chromatography;wine
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发布时间： - 摘要：Chemiluminescence emission was first observed in the interaction of TiO2 nanoparticles with NaOH solution.In the presence of surfactant of CTAB,the riboflavin can enhance the chemiluminescence intsnisty of TiO2 Nanoparticle-NaOH.Based on this,a new chemiluminescence system of TiO2 NPs-NaOH was fabricated,and a novel chemiluminescence method for determination of riboflavin was developed.Various factors affecting the CL emission intensity of the system were investigated.Under the optimum conditions,the linear range for the determination of riboflavin was in the range of 5.0×10-6-3.5×10-4 g/mL,with a detection limit of 3.0×10-6 g/mL.The relative standard deviation(n=11) for the determination of 2.5×10-5 g/mL riboflavin sodium was 2.9%.The method was applied in the determination of riboflavin preparation of tablets,and the results were in good agreement with those obtained by the pharmacopoeia method.The mechanism of the CL reaction was also discussed briefly.关键词：TiO2 nanoparticles;chemiluminescence;riboflavin
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发布时间： - 摘要：This study explores effects of different ablation-cell gases on the signal sensitivity and stability of elements in solid microanalysis by Laser ablation inductively coupled plasma mass spectrometry technique,by using NIST SRM 612 as a reference sample,and chosing the low,moderate and high mass elements such as Li（7)，Cu（63)，Y（89)，Cs（140)，Ru（175)，Th（232)，U（238) as research subjects.The results showed that there were good sensitivity and signal stability when using argon as ablation-cell gas under 0.85 L/min of argon and 0.70 L/min of carrier gas.The relative standard deviations（RSDs) were under 4% and the oxide formations（UO/U) were 0.27%.When using helium as ablation-cell gas,good sensitivity and signal stability were obtained at 0.95 L/min of argon as make up gas and 0.95 L/min of helium as carrier gas.The RSDs were about 4% and the oxide formations（UO/U) were 0.32%.The signals increased three times and the background values were very low when using helium as ablation-cell gas in comparison with using argon, and the detection limits of method were markedly improved.Therefore,helium is recommended as ablation-cell gas of the laser ablation-ICP-MS.关键词：laser ablation-inductively coupled plasma mass spectrometry;ablation-cell;carrier gas
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发布时间： - 摘要：The interaction of phlorizin with human serum albumin（HSA） was studied by fluorescence spectrometry,UV-visible absorption spectrometry and synchronous fluorescence spectrometry.The results showed that phlorizin could induce an endogenous fluorescence quenching of HSA under a mechanism of static quenching.The binding constants were determined to be 3.163 5×105（293 K）,1.774 8×105（303 K） and 1.193 5×105（313 K） L?mol-1,respectively.The binding site（n） was about 1.The thermodynamic parameters suggested that the interaction forces between phlorizin and HSA were mainly hydrogen and vander waals force.The binding distance was estimated to be 3.97 nm according to F-rster nonradiation energy transfer mechanism.The results of synchronous fluorescence spectra of phlorizin-HSA system showed that phlorizin mainly interacted with tryptophan in HSA,leading to a local change in protein conformation.In addition,the addition of the common ions could affect the binding constant of phlorizin-HSA complex.关键词：phlorizin;human serum albumin(HSA);fluorescence quenching;thermodynamic parameter
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发布时间： - 摘要：In this paper,based on the obvious enhancing effect of sodium bromide on the NaIO4-H2O2-metoclopramide weak chemiluminescence(CL) reaction system under acidic conditions and combined with the flow injection analysis，a new method for the determination of metoclopramide was proposed.Under the optimum conditions,the relative CL intensities were proportional to the metoclopramide concentrations in the range of 1.00×10-9-1.20×10-6 g/mL with a detection limit of 3.5×10-10 g/mL.The relative standard deviation(ρ=1.00×10-7g/mL,n=11) was 2.5%.The proposed method was successfully applied in the determination of metoclopramide tablets and spiked urine sample with recoveries of 96%-100%.The results were in agreement with that of the standard method关键词：flow-injection;chemiluminescence;metoclopramide;sodium periodate;hydrogen peroxide
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发布时间： - 摘要：A new method,termed as “pending templates imprinting”,to prepare protein-imprinted polymers was proposed.The molecular imprinted polymers were prepared in the presence of a real sample(chicken egg white),rather than any known purified proteins.An egg white protein-imprinted monolithic column and a control column were prepared by in situ polymerization.By comparing the electrophoretic separations of the sample in the imprinted polymeric and the control capillary,it is found that such a sample-imprinted polymer could retain abundant components of the original sample,the egg white.As a result,the signals of abundant proteins in the sample were removed or reduced in the electropherogram.Meanwhile,new peaks appeared,which stands for the enrichment of the other minor proteins in the same sample.This suggests a new way to investigate molecular imprinting,which means analyzing complicated samples based on their instinctive complexities,i.e.,through a series of polymers just imprinted by themselves.关键词：molecular imprinted polymer;pending templates;protein;separation
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发布时间： - 摘要：Ni/Al2O3,Ni/CeO2-Al2O3,Ni/ZrO2-Al2O3 and Ni/ZrO2-CeO2-Al2O3 catalysts were prepared by co-precipitation method at pH 9.0 and using Na2CO3 as the precipitant.The Ni loading(mass fraction) of the catalyst was 10%.Effects of Ce and Zr on the surface bonding energy of the catalyst were characterized by XPS,and the catalytic performances of the catalysts for the autothermal reforming of methane to hydrogen were investigated by a fixed-bed reactor.The results showed that synergy of Ce and Zr can affect the bond energy of the catalyst,and Ni/ZrO2-CeO2-Al2O3 catalyst possesses the best catalytic activity among the four catalysts.关键词：methane;autothermal reforming;hydrogen production;surface binding energy
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发布时间： - 摘要：A high performance liquid chromatographic(HPLC) method was developed for the determination of N,N-bis(2-hydroxyethyl)-p-phenylenediamine sulfate(DHPD),N,N-dimethyl-p-phenylenediamine sulfate(DMPD),N,N-diethyl-p-phenylenediamine sulfate(DEPD)and N-phenyl-p-phenylenediamine HCl(PPD).Dyes were separated on an Eclipse XDB-C18 silica column(150 mm×4.6 mm，5 μm,Agilent) using acetonitrile-25 mmol/L phosphate buffer(pH=6.0,containing 0.1% 1-heptanesulfonic acid sodium salt) as mobile phase by gradient elution at a flow rate of 1.0 mL/min and a column temperature of 25 ℃.The detection wavelengths were set at 250 nm and 280 nm.Under the optimal conditions,the linear ranges of target componds ranged from 0.1 mg/L to 400 mg/L,with correlation coefficients of 0.999 2-0.999 9.The detection limits were in the range of 18-108 mg?kg-1 and the quantitation limits were in the range of 42-320 mg?kg-1.The spiked recoveries ranged from 83% to 115% with RSDs less than 10%.The method is simple,rapid and accurate,and is applicable to the analysis of various hair dyes.关键词：hair dyes;high performance liquid chromatography(HPLC);N,N-bis(2-hydroxyethyl) p-phenylenediamine sulfate;N,N-dimethyl-p-phenylenediamine;N,N-diethyl-p-phenylenediamine sulfate;N-phenyl-p-phenylenediamine HCl
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发布时间： - 摘要：An analytical method based on ultra performance liquid chromatography tandem mass spectrometry（UPLC-MS/MS) was developed for the rapid and simultaneous determination of 11 veterinary drug residues in milk.The analytes were extracted from the sample by ultrasonic bath in acetonitrile and centrifuged.The supernatant liquid was diluted 10 times with mobile phase and filtered with a 0.2 μm micro filter,and then analyzed by UPLC-MS/MS.Under the optimized conditions, the calibration curves for 11 veterinary drugs were linear with their correlation coefficients higher than 0.998,and the limits of quantitation（LOQ,S/N=10) ranged from 0.3 μg/kg to 15 μg/kg.The mean recoveries at three spiked levels were between 81% and 117% with relative standard deviations of 0.6%-10.2%.The proposed method was successfully applied in the determination of veterinary drug residues in milk with satisfactory results.关键词：milk;several classes of veterinary drugs;ultra performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS);simultaneous determination
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发布时间： - 摘要：A method of high performance liquid chromatography combined with gel permeation chromatography（GPC/HPLC) was developed for the simultaneous analysis of methyltestosterone（MET)and diethylstilbestrol（DES) in aquatic products.The homogenized samples were extracted with diethyl ether,then cleaned by GPC using ethyl acetate-cyclohexane（1∶1)as mobile phase,follwed by a further HLB solid phase extraction.The targeted compounds were detected by HPLC-ultraviolet detector at the wavelength of 254 nm,using methanol-water（72∶28) as mobile phase,and quantified by the external standard method.The calibration curves of two compounds were linear in the concentration range of 0.02-2.0 mg/L with correlation coefficients more than 0.999.The average recoveries of MET and DES at spiked concentrations of 10.0,50.0,200 μg/kg ranged from 84% to 93%,with relative standard deviations（RSDs) less than 6.0%.The LOQs of MET and DES were 6.0 μg/kg and 5.0 μg/kg,respectively.关键词：gel permeation chromatography（GPC);solid phase extraction（SPE);high performance liquid chromatography（HPLC);aquatic products;methyltestosterone（MET);diethylstilbestrol（DES)
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