最新刊期
卷 34 ， 期 1 ， 2015
- 摘要：Three kinds of chromatographic columns were prepared by coating multi walled carbon nanotubes on the silica microspheres.To investigate retention behaviors of acidic，neutral and alkaline compounds，several kinds of aromatic compounds were used as target analytes.The separation conditions，such as ratios of methanol to water in mobile phase，column temperatures and flow rates were also investigated.In addition，the thermomechanical behaviors were discussed by calculating the thermodynamic parameters of enthalpy change，entropy change and gibbs free energy change in the process of separation.The result showed that the hydrophobicity of stationary phases was enhanced by coating carbon nanotubes.The retention mechanism was similar to reversed phase chromatographic column during the separation of sulfanilic acid and uracil.For neutral compound，the retention value and column efficiency were improved effectively because of π-π conjugate effects of carbon nanotubes.The arrangements of analytes changed from disordered to orderd，because of the addition of carbon nanotubes enhanced the retention of analytes on stationary phase.Besides，the retention mechanisms of analytes on different chromatographic columns are not dominated by one single retention mechanism，but by various mechanisms in a coordinated way.These results suggest the importance and great potential of multi-walled carbon nanotubes coated silica microspheres as stationary phase in the applications of separation and solid-phase extraction.关键词：multi-walled carbon nanotubes;silica microspheres;stationary phase;retention mechanism
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发布时间：2023-05-18 - 摘要：An HPLC-MS/MS method was established to identify multiple compounds in Longjiatongluo capsule,and a reliable HPLC-DAD/ELSD method was developed for the simultaneous anlysis of 6 active ingredients,including dioscin,pseudoprotodioscin,protodioscin,syringin,chlorogenic acid and isofraxidin.First,a qualitative method was established using a Kromasil C18 column(250 mm×4.6 mm，5 μm) with acetonitrile-water(with 0.1% formic acid) as mobile phase by gradient elution.As a result,18 compounds were identified based on MS information,and 7 of them were newly found in the preparation.Afterward,the same column and mobile phase were employed to determine the 6 active ingredients of the identified compounds.The quantitative method was developed by another gradient elution program.Dual wavelengths(syringin,254 nm;chlorogenic acid,isofraxidin,350 nm) were selected to give maximal specific detection using a diode array detector.What’s more,three steroidal saponins including dioscin,pseudoprotodioscin and protodioscin were detected with evaporative light scattering detector at an evaporation temperature of 100 ℃,a gas flow of 1.8 L/min and a nebulization temperature of 40 ℃.Good linearities of six analytes were obtained in certain concentration with correlation coefficients of 0.999 6-0.999 9,and the average recoveries(n=9) were in the range of 99.9%-100.6% with RSDs of 0.90%-1.4%.Experimental results showed that the RSDs of precision and repeatability of the six analytes were both less than 2%,and the RSD of stability of the sample in 24 h was also less than 2%.With accuracy,reliability and high repeatability,this method could be used to control the multi-compound quality of Longjiatongluo capsule.关键词：HPLC-MS/MS;multi-component determination;HPLC-DAD/ELSD;Longjiatongluo capsule
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发布时间：2023-05-18 - 摘要：A high performance liquid chromatographic（HPLC） method was developed for the determination of migration amounts of 19 UV absorbers in food contact materials.Influences of different food simulants and immersion time on the migration of UV absorbers were investigated.The results showed that the low migration of UV absorbers was found in water,3% acetic acid and low concentration ethanol,while the high migration was found in 95% ethanol and isooctane,which can be explained by their molecular structure.The migration of UV absorbers in food contact material was similar in immersion at 80 ℃ for 6 h and 40 ℃ for 10 d.The calibration curves were linear in the range of 0.5-20 mg/L for 19 UV absorbers,with correlation coefficients more than 0.999 5.The recoveries at three spiked levels ranged from 83.8% to 98.0% in 95% ethanol and isooctane.With high sensitivity,recovery and selectivity,the method could fully meet the requirements for practical work.关键词：QuEChERS;high performance liquid chromatography-tandem mass spectrometry（HPLC-MS/MS）;cuppric nonyl phenolsulfonate;tobacco;soil
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发布时间：2023-05-18 - 摘要：A liquid chromatography-tandem mass spectrometric(LC-ESI MS/MS) method was developed for the simultaneous determination of nitromidazoles and their metabolites residues,including metronidazole(MNZ),ronidazole(RNZ),dimetridazole(DMZ),metronidazole-OH(MNZOH) and 2-hydroxymethyl-1-methyl-5-nitroimidazole(HMMNI) or dimetridazole-OH(DMZOH) in aquatic products.Samples were homogeneously extracted with methanol-acetone(3∶1) in 0.5 mol/L sodium dihydrogen phosphate(NaH2PO4) solution(pH 8.0).The supernatant solution was concentrated by rotary evaporation followed by liquid-liquid partition with ethyl acetate.The fat was removed by acetonitrile-hexane distribution.The analytes were separated on a C18 column(Agilent ZORBAX SB C18 RRHD，100 mm×2.1 mm，1.8 μm) by gradient elution using a mobile phase of 0.1% formic acid solution and acetonitrile containing 0.1% formic acid,and detected by LC-ESI MS/MS under multiple reaction monitoring mode(MRM) via positive electrospray ionization(ESI+).Isotope dilution internal standard method was used for quantitation analysis．The results showed that the calibration curves of five kinds of compounds were linear in a certain concentration range(0.25-50 μg/L) with correlation coefficients of 0.998 6-0.999 7.The limits of quantitation(LOQs,S/N≥10) were 0.1 μg/kg.The average recoveries at three spiked levels of 0.1,0.5,10.0 μg/kg were between 70.7% and 105.1% with relative standard deviations(RSDs) of 1.7%-8.1%.The method showed advantages of rapidness,efficiency and high repeatability，and could meet the requirements for determination of nitromidazole residues in aquatic products．关键词：liquid chromatography-tandem mass spectrometry;nitromidazole;metabolite;aquat-ic product;residue
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发布时间：2023-05-18 - 摘要：Different plastic samples were dissolved completely in tetrahydrofuran（THF）,the impurities of high molecular weight were precipitated with methanol and separated by high speed centrifugation and filtration.The target organotin compounds were derivatized with sodium tetraethylborate in acetic acid and sodium acetate buffer solution.The ethyl derivatives of organotin compounds were extracted with n-hexane and then qualitatively and quantitatively analyzed by gas chromatography.The derivatization conditions such as derivatization time,pH value,derivatization reagent were optimized.10 organotin compounds（dimethyltin,trimethyltin,diethyltin,n butyltin,dibutyltin,tetrabutyltin,di n-octyltin,tricyclohexyltin,diphenyltin and triphenyltin） in plastic samples of PVC,PC,PS,AS and ABS were determined by gas chromatography coupled with dual column and dual detectors of mass spectrometry and flame photometric detector.10 mixed organotin compounds ranging from 0.01 to 10 mg/L were tested by the external standard method.The experimental results indicated that the correlation coefficients of calibration curves（r） for the organotin compounds were over 0.999.The average spiked recoveries were in the range of 75.1%-110.1% with relative standard deviations less than 10% in ABS,PS and PVC plastic samples，and the detection limits for 10 organotin compounds were in the range of 0.005-0.037 mg/kg.The method showed good extraction efficiency,high sensitivity and good reproducibility,and was suitable for the determination of organotin compounds in different plastic products.关键词：gas chromatography with dual columns and dual detectors;organotin compounds;mass spectrometry（MS）;flame photometric detector（FPD）;plastic products
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发布时间：2023-05-18 - 摘要：A comprehensive analytical method based on ultra performance liquid chromatography tandem mass spectrometry was developed for the simultaneous determination of fifteen prohibited androgens(e.g.adrenosterone,trenbolone,boldenone,fluoxymesterone,oxandrolone,androstenedione,nandrolone,metandienone,testosterone,dehydroepiandrosterone,clostebol,stanolone,mestanolone,4-chlorotestosterone acetate and testosterone propionate).Various cosmetic samples were extracted with methanol by ultrasonication.The extract was centrifuged,and the upper solution was then cleaned up with an Oasis HLB solid phase extraction cartridge.After chromatographic separation on an ACQUITY UPLC BEH C18(2.1 mm×50 mm,1.7 μm) column,the target compounds were analyzed under the multiple reaction monitoring(MRM) mode in positive ionization mode.The limits of quantitation(LOQs) for fifteen androgens were in the range of 1.0-20.0 μg/kg.The mean recoveries at three spiked levels ranged from 76.5% to 92.1%,with relative standard deviations of 1.3%-9.6%.The method was proved to be accurate,rapid and sensitive,and could provide a scientific basis and technical support for the inspection and production quality control of anti-acne cosmetics.关键词：anti-acne cosmetics;androgens;ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS);solid phase extraction
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发布时间：2023-05-18 - 摘要：Determination of compositions and contents of fatty acids in vegetable oils，including tea seed oil，soybean oil，peanut oil，sunflower seed oil，corn oil and sesame oil，was performed by gas chromatography-mass spectrometry（GC-MS），to investigate the use of vegetable oil fatty acids indicators to distinguish different types of vegetable oils and classification possibilities.SPSS.19.0 statistical software was used to principal component analysis，cluster analysis and discriminant analysis.The fatty acids in six vegetable oils were investigated.The results indicated that the main compositions of vegetable oils were C16∶0，C18∶0，C18∶1 cis-9，C18∶2 cis-9，12 and C18∶3 cis-9,12,15，respectively.Total contents of five major fatty acids were 98.455%，97.586%，89.019%，97.378%，98.294% and 98.021% corresponding to the tea seed oil，soybean oil，peanut oil，sunflower oil，corn oil and sesame oil，respectively.The ratios of unsaturated and saturated fatty acids（U/S） were greater than 2.000 in six kinds of vegetable oils，in which the minimum value was 2.055 for peanut oil and the maximum value was 3.976 for tea seed oil.When this data set was used，in order to obtain the reduced number of principal components，the first three principal compounds were chosen（80.060% of the total variance） because the eigenvalues were higher than 1，and which explained the reason of higher percentage of variance than each original data.The first principal component explained the higher percentage of variance 35.853%，the second principal component explained the explained 23.847% and the third principal component explained 20.360%.The study established three discriminant functions and the discriminant function correlation coefficients were greater than 0.990.The initial classification accuracy and cross-validation accuracy of tea seed oil，soybean oil，peanut oil，sunflower oil，corn oil and sesame oil all reached to 100.0%.关键词：vegetable oil;gas chromatograph-mass spectrometer（GC-MS）;principal component analysis（PCA）;cluster analysis（CA）;discriminant analysis（DA）
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发布时间：2023-05-18 - 摘要：A matrix solid-phase dispersion（MSPD） with high performance liquid chromatography tandem mass spectrometric（HPLC-MS/MS） method was established for the simultaneous determination of six estrogens（estriol,estradiol,17α-ethinylestradiol,estrone,diethylstilbestrol and bisphenol A） in sewage sludge.The 0.3 g sewage sludge sample was mixed with 1.5 g Florisil for matrix solid phase dispersion by using the new grinding method,then the mixed sample was transferred to a column and eluted with 6 mL methanol.The eluent was purified by dispersive solid phase extraction（DSPE） using HC-C18 as cleaning agent,and then concentrated to 0.6 mL by nitrogen.The six estrogens were separated upon a Syncronis C18 column using acetonitrile-water as mobile phase by gradient elution,and detected by MS under selected reaction monitoring（SRM） mode.The external standard method was used for quantitation analysis.The results indicated that six target estrogens can achieve the good linearities in the range of 1-50 μg?kg-1,with correlation coefficients higher than 0.992.The limits of detection（LODs） for the target compounds ranged from 0.12 μg?kg-1 to 0.25 μg?kg-1.Average recoveries of 6 analytes at three spiked levels ranged from 81.4% to 107.3% with relative standard deviations（RSDs） of 1.8%-9.7%.The developed method was applied in the analysis of 6 estrogens in sewage sludge samples from two sewage treatment plants in Suzhou,of which 5 target compounds except diethylstilbestrol were detected with concentration of 1.08-24.3 μg?kg-1.The method was rapid,sensitive and reliable,and was suitable for the simultaneous determination of trace estrogen in sewage sludge.关键词：estrogens;sewage sludge;matrix solid-phase dispersion extraction(MSPD);high performance liquid chromatography-tandem mass spectrometry（HPLC-MS/MS）
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发布时间：2023-05-18 - 摘要：A QuEChERS sample preparation coupled with GC-MS was established for the simultaneous determination of diethylstilbestrol and estradiol residue in fish and shrimp.The QuEChERS(Quick,Easy,Cheap,Effective,Rugged and Safe) method was used for sample preparation.The sample was extracted with ethyl acetate as extraction solvent and MgSO4 as the sorbent,cleaned up by alumina-N,and then dried using a stream of nitrogen gas,derivatized with N,O-bis(trimethylsilyl) trifluoroacetamide(BSTFA) and trimethylchlorosilane(TMCS)(99∶1),and finally determined by EI-SIM-MS.The estradiol and diethylstilbestrol were quantitatively analyzed by the internal standard method,using estradiol-D2 and diethylstilbestrol-D8 as the quantitative internal standard,respectively.Good linearities were obtained in the ranges of 1-500 μg/L for diethylstilbestrol and 1-250 μg/L for estradiol,with correlation coeffcients not less than 0.999 1.The average recoveries of diethylstilbestrol and estradiol in the grass carp and shrimp at three spiked levels of 1.5,2.5,5.0 μg/kg ranged from 86.1%to 115%,with relative standard deviations(RSD) of 0.43%-7.8%.The limits of detection(LOD,S/N≥3) for diethylstilbestrol and estradiol were 0.3 μg/kg and 0.5 μg/kg,respectively.This ensures a reliable determination at levels lower than the National Minimum Required Performance Limits(2-50 μg/kg for the xenohormones) of EU and the U.S.residue limits for veterinary drugs(0.12-3 μg/kg for natural hormones).The method was simple, sensitive,rapid and accurate，and could be successfully used for the routine analysis of diethylstilbestrol and estradiol in fish and shrimp．关键词：GC-MS;QuEChERS;diethylstilbestrol;estradiol;fish and shrimp
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发布时间：2023-05-18 - 摘要：In this paper,hordein nanoparticles were self assembled by liquid–liquid dispersion method.Effects of different parameters,including hordein concentration,isopropanol concentration,dispersion solution pH value and ionic strength on particle size and Zeta potential of self-assembled nanoparticles were systematically investigated.Smaller nanoparticles (70.0±1.8 nm) with Zeta potential 9 mV can be formed under the conditions of 55% isopropanol concentration,66 mg/mL hordein, pH 7.0 dispersion solution,0 ionic strength.Moreover,resveratrol was successfully encapsulated into hordein nanoparticles.The effects of resveratrol/hordein weight ratio on particle size,encapsulation efficiency and drug loading of resveratrol-hordein nanoparticles were studied.The results showed that the composite nanoparticles with (135.3±2.5) nm diameter,(18.91±0.02) mV Zeta potentials,90.4%encapsulation efficiency,and 18.8% drug loading were obtained under the condition of resveratrol/hordein weight ratio 1∶5.The morphological structures of both nanoparticles were smooth and spherical.The fourier transform infrared spectroscopy results showed that the electrostatic interactions and hydrogen bonds exist between resveratrol and hordein.关键词：hordein;nanoparticle;resveratrol;self-assembled;characterization
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发布时间：2023-05-18 - 摘要：The polydopamine,formed by spontaneous oxidative polymerization of dopamine,was introduced onto the inner surface of capillary,and then exploited as an adhesive coating to prepare TiO2 coated capillary column by assisting liquid phase deposition process of ammonium fluotitanate which was used as precursor of titanium dioxide.The method had the advantages of facile preparation process,operation under mild reaction conditions and the formation of a stable coating.The titanium dioxide coating was characterized by X ray photoelectron spectroscopy(XPS) and scanning electron microscope(SEM).A comparative study of electroosmotic flow(EOF) was also investigated.Five common inorganic anions and three alkaloids were selected as the test analytes.Effects of several factors,such as composition of background electrolytes(BGEs),buffer concentration and pH value,on separation performance were investigated.The results showed that,under the optimal conditions,both five inorganic anions and three alkaloids could be well separated.关键词：polydopamine;titanium dioxide;capillary electrochromatography;inorganic anions;alkaloids
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发布时间：2023-05-18 - 摘要：A solid phase membrane extraction with gas chromatography-mass spectrometric（GC-MS） method was established for the simultaneous determination of various trace amounts of phenol compounds.The solid phase membrane extraction technology was developed to extract trace amounts of phenol compounds in raw water.Some factors influencing the extraction efficiency of solid phase membrane，including type of eluent，elution volume，initial pH and elution rate were optimized.The separation was performed on a DB-5MS column.Gas chromatography-mass spectrometry（GC-MS） was used to quantitatively analyze the target compounds.The experimental results indicated that with the initial pH value of 2.0 and the elution rate of 1 mL/min，selecting 10 mL dichloromethane-ethyl acetate（1∶1） as extraction eluent，the average recoveries could reach to 82.3%-97.1%.In the optimal conditions，the calibration curves were linear between peak areas and mass concentrations of phenol compounds in the range of 1- 800 μg/L，with correlation coefficients（r2） more than 0.996.The limits of detection（MLD） of phenol compounds were not more than 0.017 μg/L.The precision of the method is high，with relative standard deviations（RSD，n=8） of 1.6%-4.3%.The method was successfully applied in the analysis of trace phenol compounds in water samples collected from the Beijiang River，China.With the advantages of short extraction time，sensitivity，accurancy and simplicity，the method could meet the requirements for the detection of trace phenol compounds in raw water and could significantly improve the efficiency in the analysis of phenol compounds.关键词：solid phase membrane extraction;gas chromatography-mass spectrometry（GC-MS）;phenol compound;trace amounts
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发布时间：2023-05-18 - 摘要：A high performance liquid chromatographic(HPLC) method was developed for the simultaneous detection of eight synthetic dyes in hair dyes.The samples were initially extracted with methanol,then separated on an XB-C18 column with acetonitrile and 0.02 mol/L ammonium acetate solution as mobile phases,and detected with DAD.The best detection wavelengths for HC Red No.3,HC Yellow No.4,HC Orange No.1,Disperse Violet 1,Disperse Black 9,HC Yellow No.2,HC Blue No.7 and HC Red No.1 are 240,410,240,240,240,240,450,270 nm,respectively.The external standard calibration curves were used for quantitative analysis.The calibration curves for 8 dyes were linear in the range of 0.5-100.0 μg/mL with correlation coefficients not less than 0.999 3.The limits of detection were 0.70 mg/kg for HC Red No.3,HC Yellow No.4,HC Orange No.1 and Disperse Violet 1,and 2.50,0.60,0.35 and 0.50 mg/kg for Disperse Black 9,HC Yellow No.2,HC Blue No.7 and HC Red No.1,respectively.The spiked recoveries were in the range of 85.4%-99.8% with relative standard deviations（RSDs,n=6） of 1.1%-3.6%.The precision,accuracy,mean recoveries and the matrix effects were satisfied for the requirements of cosmetic sample measurement.The proposed method was applied in the determination of 8 dyes in actual samples.The method is quick,easy,effective,sensitive and accurate,and could meet the requirements for the determination of eight synthetic dyes in hair dyes.关键词：hair dyes;synthetic dyes;HC dyes;disperse dyes;HPLC
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发布时间：2023-05-18 - 摘要：A rapid and sensitive analytical method for the determination of cuppric nonyl phenolsulfonate residues in tobacco and soil samples was developed and validated based on QuEChERS（Quick,Easy,Cheap,Effective,Rugged and Safe） and high performance liquid chromatography-tandem mass spectrometry（HPLC-MS/MS）.Factors affecting the decomplexation efficiency by different compounds were investigated.The effects of type and volume of dispersive solvent on the clean up of tobacco and soil extracts were also assessed.Residues in the samples were decomplexated by sodium sulfide,extracted with acetonitrile and then cleaned up with primary secondary amine（PSA）.The product nonyl phenol sulfonic acid in the extract was separated by gradient elution using a mobile phase of acetonitrile-water and then analyzed by electrospray ionization in positive ion mode（ESI+） under multiple reaction monitoring（MRM） mode.Linearity was assessed by calibration curve in blank matrix to compensate for matrix effect.Good linearities（r >0.99） were obtained for nonyl phenol sulfonic acid in the matrix matched standards in the range of 0.001-1.0 mg?L-1.The average recoveries at spiked levels of 0.01-2.0 mg?kg-1 were in the range of 84.7%-92.5% for green tobacco leaf,87.1%-103.2% for dried tobacco leaf and 83.0%-90.9% for soil,with relative standard deviations（RSDs） of 6.9%-8.3%,5.8%-10.6% and 6.0%-9.0%,respectively.The limits of detection（LOD） were 5.5×10-5 mg?kg-1,while the limits of quantitation（LOQ） were determined as 0.01 mg?kg-1 for green,dried tobacco leaf and soil.This method is easy,quick and effective,and could be applied in the determination of cupric nonyl phenolsulfonate in tobacco and soil samples.关键词：QuEChERS;high performance liquid chromatography-tandem mass spectrometry（HPLC-MS/MS）;cuppric nonyl phenolsulfonate;tobacco;soil
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发布时间：2023-05-18 - 摘要：The water-soluble CdTe quantum dots(QDs) were synthesized in aqueous solution using 3-mercaptopropionic acid(MPA) as stabilizing agents.It was found that there was an appreciable overlap between excitation spectrum of CdTe QDs and absorption spectrum of tetracycline(TCs).Thus,the fluorescence inner filter effect(IFE) system was constructed between CdTe QDs(fluorophore) and TCs(absorber).Based on this IFE system,a synchronous fluorescence quenching method for the determination of TCs was developed.When Δλ was set at 220 nm,the maximum emission wavelength of synchronous fluorescence was 297 nm.Under the optimal conditions,a good linearity was obtained between quenched synchronous fluorescence intensity of CdTe QDs and concentration of TCs in the range of 1.0×10-6-1.0×10-5 mol?L-1.The correlation coefficient was 0.999 and the detection limit was 2.5×10-8 mol?L-1.With high sensitivity and good selectivity,the proposed method was successfully applied in the determination of TCs in milk samples with spiked recoveries of 97.0%-104.3%.关键词：CdTe quantum dots;tetracycline;inner-filter effect;synchronous fluorescence quenching
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发布时间：2023-05-18 - 摘要：A simple colorimetric biosensor based on the different adsorption ability of gold nanoparticles（AuNPs） on single-strand DNA（ssDNA） and G-quartet was presented to determine Pb2+ concentration in water.The guanine-rich ssDNA can be easily adsorbed onto the surface of AuNPs preventing them from aggregation in high ionic strength solution.In the presence of Pb2+,the conformation of ssDNA was changed from random coil to rigid G-quartet structure which could not bind to AuNPs,leading to the aggregation of AuNPs,accompanied by color changing from red to blue and red shift of the maximum absorption wavelength.Under the optimal conditions,the absorption ratio of A630/A520 was proportional to Pb2+ concentration in the range of 0.1-10 μmol/L with a detection limit（3σ） of 50 nmol/L.There were almost no interference from other metal ions.With the advantages of high sensitivity and selectivity,simplicity of preparation and manipulation,lowcost,fast response（within 1 min）,the presented method is very suitable for real-time and on-site application in environmental protection.关键词：gold nanoparticles;colorimetric method;guanine-rich ssDNA;Pb2+ detection
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发布时间：2023-05-18 - 摘要：A reversed-phase high performance liquid chromatographic method was developed for the simultaneous determination of mannan and β-glucan in yeast cell wall samples using 3-phenyl-3-methyl-5-pyrazolone(PMP) as pre-column derivatization reagent.The polysaccharides in the sample were hydrolyzed with HCl into mannose and glucose form,and the contents of mannan and β-glucan were calculated with the concentration of each monosaccharide.The monosaccharides were derivated with PMP,and the derivatives were separated on a C18 column(4.6 mm×250 mm,5 μm) using 0.02 mol/L ammonium acetate-acetonitrile(80. 5∶19.5) as mobile phase by isocratic elution.The detection wavelength was set at 250 nm.The results showed that good linear ranges for mannose and glucose were obtained from 10.0 mg/L to 1 000 mg/L with correlation coefficients(r2) larger than 0.999.The mean recoveries were in the range of 88.1%-91.0% at spiked levels of 28.0-80.0 mg,and the relative standard deviations(RSDs) were less than 3%.The limits of detection(LODs) were 0.10 mg/L and 0.08 mg/L for mannose and glucose,respectively.The method is sensitive,accurate and reliable，and is suitable for the determination of mannan and β-glucan in the yeast cell wall samples.关键词：yeast cell wall;mannan;β-glucan;pre-column derivatization;reversed phase high performance liquid chromatography(RP-HPLC)
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发布时间：2023-05-18 - 摘要：Mn，Cu,Zn in tobacco were detected by flame atomic absorption spectrometry,and Cd，Cr，Pb were detected by graphite furance atomic absorption spectroscopy.The method of HNO3-H2O2 microwave digestion was used to obtain total amount of heavy metals.The water soluble speciation of heavy metals were gained by ultrasonic water extraction method for primary speciation analysis,and five species of heavy metals were acquired by Tessier step by step extraction method for the second speciation analysis.The results showed that the linearity was good in detection of six kinds of heavy metals by atomic absorption spectrometry,and the correlation coefficients were not less than 0.998 8 with detection limits of 0.16-3.1 μg?L-1.Mn，Cu，Zn and Cd elements in tobacco were mainly in the form of exchangeable speciation and carbonate bounded speciation while Cr was mainly in residual speciation and Pb was mainly in carbonate bounded speciation and residual speciation.关键词：atomic absorption spectrometry;tobacco;heavy metals;total amount;primary speciation analysis;the second speciation analysis
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发布时间：2023-05-18 - 摘要：A high performance liquid chromatography-electrospray ionization triple-quadruple tandem mass spectrometric（HPLC-ESI-MS/MS） method was established for the determination of 18 sulfonamides and their potentiators in veterinary pharmaceutical powder，including sulfadimidine，sulfacetamide，sulfamethizole，sulfachloropyridazine，sulfamethoxazole，sulfathiazole，sulfamonomethoxine，sulfamerazine，sulfadoxine，sulfapyridine，sulfameter，sulfamethoxypyridazine，sulfaphenazolum，sulfadimethoxypyrimidine，sulfisoxazole，sulfaquinoxaline，sulfadiazine and trimethoprim.The 18 banned additives were extracted with methanol-H2O（90∶10）.Then the reconstituted sample solution was analyzed by HPLC-MS/MS under positive ion mode，with a C18 column（2.1 mm×150 mm，5 μm） as analytical column.The detection limits of 18 sulfonamides were all 10 μg/kg.The calibration curves were linear in the range of 50-2 000 μg/kg，with correlation coefficients more than 0.99.The method was validated at spiked levels of 50，200,1 000 μg/kg，and the overall recoveries were in the range of 86.8%-115% with relative standard deviations（RSDs） of 1.0%-9.7%.关键词：sulfonamides;high performance liquid chromatography tandem mass spectrometry（HPLC-MS/MS）;veterinary pharmaceutical powder
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发布时间：2023-05-18 - 摘要：The traditional analysis method of soil can not obtain the required soil information in a short time because of its disadvantages of time consumption and high cost.How to detect the soil information rapidly and accurately is an inevitable requirement for modern agriculture.As a rapid,inexpensive,non-destructive and pollution free analytical method,diffuse reflectance infrared spectroscopy is widely used in many fields,and it has been no doubt an important approach to obtain soil quality related messages.The potentials of near-infrared reflectance spectroscopy(NIR,780-2 500 nm) and diffuse mid-infrared reflectance spectroscopy(MIR,2 500-25 000 nm) to analyse the chemical and physical characteristics of soil attract many countries attentions.In the present paper,the principles and methods of near-and mid-infrared diffuse reflectance spectroscopic techniques were introduced concisely.The applications of this technique in analysis of soil were reviewed，and some comments and prospects concerning the future development of this technique were presented.关键词：Near-infrared reflectance spectroscopy(NIR);mid-infrared reflectance spectroscopy(MIR);soil;chemometrics
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发布时间：2023-05-18
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