最新刊期
卷 32 ， 期 3 ， 2013
- 摘要：A method was developed for the determination of dicyandiamide in infant milk powder by high-performance liquid chromatography-mass spectrometry（LC-MS/MS）.The conditions of extraction and parameters of LC-MS were optimized.The sample was extracted with water,precipitated with acetonitrile,then separated on a Thermo syncronis column using mixture of acetonitrile（containing 0.2% formic acid）-0.1% formic acid（containing 10 mmol/L ammonium formate）（95∶5） as mobile phase at a flow rate of 0.3 mL/min.The detection of dicyandiamide was performed by positive-ion electrospray ionization mass spectrometry（ESI-MS） utilizing multiple reaction monitoring of two parent-daughter ion pairs:m/z 85/68 and 85/43.A good linear relationship was obtained in the range of 0.2-100 μg/L,with a correlation coefficient of 0.999 8.The spiked recoveries at different spiked levels were in the range of 79%-83%.The detection limit of dicyandiamide was 0.1 μg/L,and the quantitatiion limit of method was 5 μg/kg.The results indicated that the method was rapid,selective,sensitive and stable enough to examine dicyandiamide in infant milk powder.关键词：dicyandiamide;liquid chromatography-mass spectrometry（LC-MS/MS）;infant milk powder
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发布时间： - 摘要：A rapid and selective method was successfully developed using magnetic molecularly imprinted polymer（MMIP） as sorbent for the extraction of methomyl from vegetable samples.The MMIP was synthesized using methomyl as template molecule，methacrylic acid as functional monomer，ethylene glycol dimethacrylate as crosslinking agent and Fe3O4 magnetite as magnetic component.The MMIP was characterized by Fourier transform infrared spectra，scanning electron microscope and physical property measurement system.Scatchard plot analysis revealed that two kinds of different binding sites existed in MMIP,in which the maximum amount of apparent binding and dissociation constant of binding sites were as follows:Qmax1=0.053 04 mmol/g，Kd1=0.314 35 mmol/L;Qmax2=0.130 51 mmol/g，Kd2=1.921 22 mmol/L.The kinetic property of MMIP was well fitted to the pseudo-second-order equation.The result indicated that MMIP had high selectivity towards methomyl over reference compound.The effects of extraction solvent，MMIP amount，extraction time，shaking rate，desorption solvent on recoveries of methomyl were investigated.Under the optimal conditions，the limit of detection of methomyl was 0.012 mg/kg，the spiked recoveries of methomyl were in the range of 86%-94% with relative standard deviations（RSDs） of 2.2%-6.1%.The method was applied in the determination of methomyl in vegetable samples，including cabbage，pakchoi，tomato，cucumber and pepper，in which，methomyl was detected in the tomato sample with concentration of 1.135 mg/kg.Compared with the traditional method，the proposed method is rapid and effective，and is promising for the analysis of pesticide residues in food samples.关键词：magnetic molecularly imprinted polymer;methomyl;vegetable;high performance liquid chromatography
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发布时间： - 摘要：Based on the deficiency of qualitative detection of traditional characteristic peak comparison,a new method of the spectral pattern recognition based on judging the subspace coincidence was developed for the qualitative detection of nine mixed alcohols solution with different proportions.The spectra of mixed alcohol were treated as a vector in the method.First,the angle of raman spectra of mixed alcohol and the gather of standards were calculated.Then the least number of subspace,which contains the standard samples composed of the mixed alcohol undetermined,was selected according to the change of the subspace angle.Finally,it is successful to complete the qualitative recognition of all nine mixed alcohols of different proportions,and the detection rate of the method is 100%.With advantages of accurancy,simplicity,sensitivity and time saving,the method was suitable for the qualitative detection of multicomponent mixed system.关键词：Raman spectra;multicomponent qualitative detection;subspace angle;chemometrics
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发布时间： - 摘要：A simple，fast and sensitive method was developed for the determination of dithiocarbamates,including tiezene(EBDC) and pestanal(PBDC),by optimizing the parameters of LC-MS/MS and extraction buffer.Under the optimized conditions，the calibration curves of EBDC and PBDC were linear in the range of 2-100 μg/L with correlation coefficients not less than 0.997.The limits of detection（LODs，S/N＞3 ） of EBDC and PBDC were 2 μg/kg for cauliflower,turnip and pea,and the limits of quantitation（LOQs，S/N＞10 ） of EBDC and PBDC were 10 μg/kg for turnip and pea，and 15 μg/kg for cauliflower.The recoveries in cauliflower，turnip and pea samples at spiked concentration levels of 5-100 μg/kg ranged from 83% to 96% with relative standard deviations（RSDs） of 4.4%-10.5%.The method could meet the requirement for the analysis of dithiocarbamates in foodstuffs.关键词：LC-MS/MS;foodstuffs;dithiocarbamate;determination
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发布时间： - 摘要：A multi residue analysis was developed for the determination of 230 pesticides,which belonged to different chemical classes,in fruits and vegetables.The sample was prepared by the modified QuEChERS method.The detection of 230 pesticides was performed by liquid chromatography - tandem mass spectrometry(LC-MS/MS) with the external standard method.The calibration curves of target compounds were linear in the range of 0-15 μg/L with correlation coefficients more than 0.996.The limits of quantitation were lower than 1.0 μg/kg for 80% analytes.The recoveries at spiked levels of 5,10 and 20 μg/kg were in the range of 60%-120% with RSD less than 20%.An advanced software features associated with MRM method development(S-MRM) was adopted.The proposed method was applied successfully in the residue determination of multi-pesticides in commercial fruits and vegetables samples with its advantages of simiplicity and stableness.关键词：multiresidue analysis;fruits and vegetable;QuEChERS;LC-MS/MS;scheduled multiple reaction monitoring(S-MRM) mode
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发布时间： - 摘要：Three dimensional fluorescence spectral characteristics of tea polyphenols solution,and effects of different concentrations,pH values,buffers,organic solvents and other factors on the visible light region fluorescence were studied by using three dimensional fluorescence spectrometric technology.Results showed that,three dimensional fluorescence spectra of tea polyphenols in H2O could be divided into 3 regions(showed by λex/λem):RegionⅠ:210 nm/315 nm,270 nm/315 nm;Region Ⅱ:335 nm/395 nm；Region Ⅲ:490 nm/515 nm.Excitation and emission wavelengths of the maximum fluorescence shifted towards the longer wavelength with the increase of tea polyphenols concentration.Region Ⅲ fluorescence in visible light region can be sensitively detected at a concentration of 3 mg/mL and pH value of 7.55.Commonly used buffer solutions(e.g.KH2PO4-NaOH buffer,Na2HPO4-citric acid buffer,phosphate buffer and Tris-HCl buffer) have certain degrees of sensitization effect to fluorescence intensity in Region Ⅲ.Polar protic solvents was beneficial for the fluorescence emission in Region Ⅲ.This study could provide new ideas and inspirations for fast,non-destructive analysis and developing application of tea polyphenols.关键词：tea polyphenols;three dimensional fluorescence spectrum;pH value
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发布时间： - 摘要：In order to establish the quality control system of retigabine active substances,a headspace gas chromatographic method was established and validated for the determination of residual solvents of ethanol,hexane,tetrahydrofuran and triethylamine in retigabine active substances,by using FID as the detector and N,N-dimethylformamide as sample solvent.The detection of four residual solvents was performed on a DB-624 capillary column with vial equilibration temperature of 110 ℃ and equilibration time of 15 min.The limits of detection(LOD) for ethanol,hexane,tetrahydrofuran and triethylamine were 0.007 5%,0.000 48%,0.002 4% and 0.01%,respectively.The relative standard deviations(RSDs) of peak areas were below 2.1%.The average recoveries were in the range of 100%-102%, and the correlation coefficients were above 0.995.The result indicated that the method showed the advantages of high sensitivity,good accurancy and linearity.The established method was applied in the quality control of three batches of retigabine,and only ethanol and hexane were checked out with the highest residual level of 0.149% and 0.022%，respectively,which did not exceed the limited quantity.关键词：retigabine;headspace gas chromatographic method;residual solvents;ethanol;hexane;tetrahydrofuran;triethylamine
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发布时间： - 摘要：In this paper，chemical composition of complex flavor formula was analyzed by means of GC-MS and the computer-aided flavor-adjusting software based on chemometrics，then the flavor formula was further refined under the experience of flavorist.The simulated flavor was evaluated by the chemical composition and odor characteristics.The results showed that the similarity of chromatographic fingerprint between the original and simulated flavors is up to 97.8%.After the evaluation by a professional team formed by flavorist，the smell characteristics of the simulated is very similar to that of the original flavor.Therefore，a potential method based on applied instrument analysis，chemometrics methods and expert knowledge of flavorist was proposed for flavor analysis.关键词：tobacco flavor;GC-MS;chemometrics;analysis and formulation
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发布时间： - 摘要：An online SPE coupled with HPLC method was developed for the determination of chlorogenic acid and phillyrin in ShuangHuangLian oral liquid and capsule.Acclaim Polar AdvantageⅡC18（4.6 mm×50 mm×3 μm）was used as online one dimensional column with a mobile phase consisting of methanol-1% acetic acid-water by gradient elution with a right pump at a flow rate of 0.8 mL/min.The left pump was used to analyze the elute in SPE using Acclaim C18（4.6 mm×150 mm×5 μm）as its two dimensional analytical column by gradient elution with acetonitrile-1% acetic acid-water as mobile phase at a flow rate of 1.0 mL/min.The UV detector was set at 278 nm.Good linear relationships were observed between peak areas and concentrations in the ranges of 0.021-0.42 g/L for chlorogenic acid and 0.014-0.28 g/L for phillyrin，with correlation coefficients of 0.999 5 and 0.999 7，respectively.The average recoveries of phillyrin and chlorogenic acid in ShuangHuangLian oral liquid were 100% and 99%，respectively.This method was simple and fast,and had good speciality and repeatability.关键词：online solid-phase extraction;HPLC;ShuangHuangLian oral liquid;chlorogenic acid;phillyrin
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发布时间： - 摘要：A method for the simultaneous determination of 12 banned and restricted substances，including enoxacin，ciprofloxacin，ofloxacin，lincomycin，clindamycin，clindamycin phosphate，chloramphenicol，p-nitropheny-2-amino-1-3-propanediol，sulfamethoxazole，metronidazole，tindazole and salicylic acid was developed by reversed phase high performance liquid chromatography（RP-HPLC） with diode array detector（DAD）.The above twelve substances were extracted ultrasonically with methanol-0.1 mol/L hydrochloric acid（1∶1）.The analytes were separated on an ACE C18（250 mm×4.6 mm，5 μm） column by gradient elution with 0.025 mol/L phosphoric acid triethylamine-acetonitrile as mobile phase,and detected at the wavelengths of 210 nm and 277 nm，respectively.The flow rate was set at 1.5 mL/min and the column temperature was 40 ℃. Identification of the 12 banned and restricted substances was achieved by the retention time and the DAD spectra.Quantification analysis was performed by the external standard method.Under the optimal conditions，the detection limits of twelve substances were in the range of 5-50 μg/g.The calibration curves were linear in the range of 25-1 000 mg/L for lincomycin，clindamycin，clindamycin phosphate， and 5-200 mg/L for the rest of analytes，with correlation coefficients more than 0.997.The average recoveries at two spiked levels ranged from 88% to 115% with RSDs of 0.4%-3.0%.The results indicated that the method was simple，sensitive and accurate，and was suitable for the determination of 12 banned and restricted substances in ant-acne cosmetics.关键词：high performance liquid chromatography（HPLC）;anti-acne cosmetics;banned and restricted substances
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发布时间： - 摘要：A novel imprinted TiO2 nanoparticles were synthesized via a sol-gel process using L-tryptophan(L-Trp) as temple molecules and TiO2 nanoparticles as imprinted matrix.The imprinted TiO2 nanoparticles were investigated by scanning electron microscopy and infrared spectroscopy.The result indicated that L-Trp was imprinted into TiO2 nanoparticles successfully.Appropriate template cavities in TiO2 nanoparticles were formed after the template molecules were removed by treatment with 1% ammonia solution.Fluorescence spectrophotometry was used to study the separation abilities of L-Trp and D-tryptophan(D-Trp) in the imprinted TiO2 nanoparticles.The results showed that imprinted TiO2 nanoparticles had a high selectivity to L-Trp,and the separation factor was 2.42 under the optimum molar ratio of L-Trp to titanium precursor(1∶0.2) in pH 6.0 solution.关键词：sol-gel;molecular imprinting;L-tryptophan;titanium dioxide nanoparticles
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发布时间： - 摘要：A high performance liquid chromatographic（HPLC） method was developed for the simultaneous extraction and determination of ten phenols,including pentachlorophenol,2,3,4,5-tetrachlorophenol,2,3,4,6-tetrachlorophenol,2,3,5,6-tetrachlorophenol,2,4,5-trichlorophenol,2,4,6-trichlorophenol,2-phenylphenol,3-phenylphenol,2-naphthol and 4-nitrophenol in textiles.The samples were ultrasonically extracted with methanol.The separation and quantification of ten phenols were achieved on an ZORBAX SB-C18 column（4.6 mm×150 mm，5 μm ） with mobile phase of acetonitrile-0.01 mol/L phosphate and the diode array detector（DAD） at 220 nm and 310 nm.Lab-built UV spectroscopy library and external standards were employed for the identification and quantification of target compounds.The result indicated that the calibration curves of ten phenols showed good linear relationships between peak areas and concentrations in the range of 0.3-37 mg/L,with their correlation coefficients of 0.999 1-0.999 5The limits of detection（LODs,S/N≥3） of ten phenols were in the range of 0.003 0-0.041 1 mg/kg,and the limits of quantitation（LOQs,S/N≥10） were 0.010 0-0.137 0 mg/kg.The average recoveries of ten phenols from 3 typical textile matrices including cotton,wool and ramie, at three spiked concentration levels were in the range of 81%-105% with relative standard deviations（RSDs） of 1.7%-8.5%.The proposed method could be used to identify and detect the 10 phenols simultaneously,which makes it effective in residue surveillance of phenols in textile samples.关键词：textile;phenols;high performance liquid chromatography（HPLC）
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发布时间： - 摘要：A novel ionic liquid based ultrasonic assisted extraction（ILUAE）combined with reverse phase high performance liquid chromatography tandem UV detection（HPLC-UV） was first developed to isolate and determinate flavonoids in rhododendron mucronatum leaves.The 1-butyl-3-methylimidazolium chloride（［BMIM］Br） aqueous solution was selected as extraction solvent.The sample was separated on a Phenomenex C18 column using acetonitrile-0.25% acetic acid as mobile phase by gradient elution at a flow rate of 1.0 mL?min-1.The UV detection wavelength was set at 355 nm.The quantitative analysis of rutin，quercetin and kaempferol were carried out by the external standard method.Under the optimal extraction conditions，the calibration curves of rutin，quercetin，and kaempferol were linear in the ranges of 0.064-128，0.076-152 and 0.064-128 mg?L-1，respectively，with correlation coefficients of 0.999 9.Their limits of detection（LODs，S/N=3） were 0.006 6，0.009 2 and 0.005 0 mg?L-1，respectively.The spiked recoveries of three compounds ranged from 90% to 97%.The results indicated that the proposed method was an environment-friendly，easy to operation and efficient technique for sample preparation，thus it could provide an alternative means for assaying flavonoids in the rhododendron mucronatum leaves.关键词：ionic liquid;ultrasonic-assisted;high performance liquid chromatography(HPLC);flavonoid;rhododendron mucronatum leaves
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发布时间： - 摘要：An HPLC method was developed for the enantioseparation of 13 flavonoids on chiral columns of Chiralpak AD-H (250 mm×4.6 mm，5 μm) and Chiralcel OZ-H(250 mm×4.6 mm，5 μm).The influences of type and percentage of alcohol modifier on the chiral recognition were examined.Effects of trifluoroacetic acid(TFA) in the mobile phase were also studied.The optimized chromatographic conditions for 13 racemic flavonoids were as follows：mobile phas：n-hexane-isopropanol (ethanol)-TFA(75∶25∶0.1),flow rate:0.5 mL?min-1,column temperature：35 ℃,UV detection wavelength:290 nm.Under the optimal conditions,13 racemic flavonoids were successfully enantioseparated at the baseline on Chiralpak AD-H and Chiralcel OZ-H chiral columns.This study illustrated the potentials of Chiralpak AD-H and Chiralcel OZ-H chiral columns in the chiral separation of flavonoids and their analogues.关键词：Chiralpak AD-H;Chiralcel OZ-H;chiral separation;racemic flavonoids;high performance liquid chromatography(HPLC)
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发布时间： - 摘要：Multi-walled carbon nanotubes(MWNT) were doped to modify polybromocresol green film(PBG),and four kinds of modified electrodes were prapared by different modification methods.The modified electrodes were characterized by scanning electron microscopy,AC impedance and cyclic voltammery.The results indicated that the electrical activation areas were increased significantly at the four kinds of modified electrodes,in which the polybromocresol green film/multi-walled carbon nanotube composite film(PBG/MWNT/GC) electrode was the best one to develep the electric activity of MWNT and PBG.The electrode was applied in the study of the electrochemical behavior of 8-hydroxyquinoline(8-HQ),and the voltammetric response of 8-HQ on the four modified electrodes were improved significantly.Among them,the potential of oxidation peak of 8-HQ on PBG/MWNT/GC was shifted negatively and its peak current was the largest(about 4.5 times on that of the bare glass carbon electrode),indicating that the electric catalysis of 8-HQ on PBG/MWNT/GC was largely enhanced.The reaction of 8-HQ on PBG/MWNT/GC electrode was adsorption-controlled irreversible electro-oxidation process,and its numbers of electron transfer and proton were both 1.A good linear relationship was observed between peak current and concentration of 8-HQ in the range of 4.0×10-6-3.5×10-4 mol/L(r=-0.997 2) with a detection limit(S/N=3) of 1.96×10-8 mol/L.PBG/MWNT/GC is avaible to determine 8-HQ quickly and easily.关键词：8-hydroxyquinoline;bromocresol green;multi-walled carbon nanotubes;modified electrode;modified
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发布时间： - 摘要：A prediction model was established for the rapid analysis of carbofuran residue in duck meat by synchronous fluorescence spectroscopy method，based on the condition that the strong fluorescent derivatives can be generated in the reaction between carbofuran hydrolyzate and phthaldialdehyde（OPA） in the presence of mercaptoethanol.The 3D synchronous fluorescence spectra of the duck meat containing carbofuran were analyzed，and 120 nm was selected as the optimum wavelength difference.19 wavelengths between 240 nm and 450 nm were selected as the input features for quantitative analysis models using genetic algorithm combined with the root mean square error of cross-validation.The performances of three regression models，SVR,PCR and PLS were compared，and the results showed that the prediction of SVR regression model was the best，the determination coefficient（r2） and the root mean squared error of prediction（RMSEP） for the prediction samples were 0.999 4 and 0.878 7，respectively.The results approved that the method of synchronous fluorescence analysis with SVR had a good performance and accuracy in quick test，and was applicable for the detection of carbofuran residue in duck meat.关键词：synchronous fluorescence spectroscopy;SVR;carbofuran;duck meat
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发布时间： - 摘要：The interaction between ponceau 2R(P2R) and bovine serum albumin(BSA) and their interaction mechanism were investigated by fluorescence spectroscopy,synchronous fluorescence spectroscopy,UV absorption spectroscopy and molecular modeling under the simulated physiological condition.The results showed that the intrinsic fluorescence of BSA was quenched by P2R,the quenching reasons were both static quenching and non-radiation energy transfer.Binding constant(Ka) and binding sites(n) at different temperatures were calculated.The results of corresponding thermodynamic parameters as well as binding distance between BSA and P2R were obtained.The synchronous fluorescence spectrometry revealed that P2R had no impact on the conformation of BSA.The result of molecular modeling indicated that P2R can bind with BSA with hydrophobic force and hydrogen bonding as the main acting force.关键词：molecular modeling;ponceau 2R;BSA;spectroscopy;interaction
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发布时间： - 摘要：A capillary electrophoresis（CE）with UV detection method was developed for the determination of ellagic acid and punicalagin in pomegranate peel,grown in different origins.Effects of some important factors,such as pH value,concentration of running buffer,separation voltage and injection time were investigated.The optimum conditions were as the follows:running buffer:50 mmol/L borax buffer（pH 8.7）,separation voltage:20 kV,injection time:9 s/20 kV.Under the optimum conditions,two analytes could be separated within 12 min at the detection wavelength of 260 nm.The good linearities between peak area and mass concentration were obtained in the ranges of 5.0×10-7-5.0×10-5 g/mL and 2.0×10-6-5.0×10-5 g/mL for ellagic acid and punicalagin,with their detection limits of 1.0×10-7g/mL and 1.3×10-6g/mL,respectively.The relative standard deviations（RSD,n=7） for the peak areas of ellagic acid and punicalagin were 2.4% and 2.2%,respectively.The average recoveries were 101% for ellagic acid and 98% for punicalagin.It is found by t-test that there were no significant differences between this method and the HPLC method.The proposed method was simple，rapid and accurate,and was successfully applied in the determination of the analytes in pomegranate peel samples.关键词：capillary electrophoresis;pomegranate peel;ellagic acid;punicalagin
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发布时间： - 摘要：A simple and efficient method based on solid phase extraction(SPE) cartridge and liquid chromatography-tandem mass spectrometry(LC-MS/MS) was developed for the determination of butylene fipronil residue in bamboo shoots.Samples were extracted with acetonitrile,and the extract was purified with PSA SPE column.The detection of butylene fipronil was performed by LC-MS/MS under multiple reaction-monitoring mode(MRM).Butylene fipronil could be completely separated in 15 min with an excellent linear relationship in the range of 5.0-100.0 μg/L.The detection limit(S/N=3) and quantitation limit for butylene fipronil were 0.21 μg/kg and 0.69 μg/kg，respectively.The recoveries of butylene fipronil at three spiked levels of 4,8,32 μg?kg-1 were in the range of 76%-103% with relative standard deviations of 3.2%-9.9%.Compared with GC and GC-MS method，the proposed method was rapid，sensitive and accurate，and could meet the requirement for the determination of butylene fipronil residue in bamboo shoots.关键词：liquid chromatography-tandem mass spectrometry(LC-MS/MS);butylene fipronil;bamboo shoot;residue
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发布时间： - 摘要：A sensitive and reliable method was developed for the quantitative determination of three metabolites of trichloroethylene，e.g.monochloroacetic acid(MCA)，dichloroacetic acid(DCA) and trichloroacetic acid(TCA)，in urine sample.Three metabolites were derivatized by ethanol esterification in the presence of ferric chloride acted.Effects of esterification temperature,esterification time and amounts of ferric chloride and ethanol were discussed，and the optimization conditions were using 4 mL urine sample mixed with 1.05 mmol ferric chloride and 2.0 mL ethanol to derivatize for 50 min in 90 ℃ water bath.The three ethyl esters in sample were simultaneously determined by derivatization gas chromatography coupled with electron-capture detection after extracted with 2 mL hexane.The method showed good linearities in the ranges of 40-2 400，20-1 000 μg/L and 10-500 μg/L for monochloroacetic acid，dichloroacetic acid and trichloroacetic acid，with correlation coefficients of 0.999 8，0.999 3 and 0.999 2，respectively.The average spiked recoveries of three metabolites in urine sample were 104%，109%and 106%，with their detection limits(S/N=3) of 4.67，1.32 and 0.27 μg/L，respectively.With the advantages of simplicity,requirements for relatively moderate reaction condition and non-corrosion reagents,the method was applied in the quantitative analysis of three metabolites in the urine samples from workers exposed to the trichloroethylene contaminant with satisfactory results.关键词：monochloroacetic acid;dichloroacetic acid;trichloroacetic acid;derivatization;gas chromatography
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发布时间： - 摘要：A novel 1-［（phenylamino）-（phenylimine）］methylbenzimidazole［C20H16N4］was synthesized with N,N′-diphenylthiourea and benzimidazole as the starting material and neodymium nitrate hexahydrate as catalyst.The title compound was characterized by X-ray single-crystal diffraction,IR and elemental analysis.The crystal structure of the compound belongs to monoclinic system with space group P21/c.The cell parameters were as follows: a=0.921 6（10） nm,b=1.021 2（11） nm,c=1.879 6（17） nm,β=111.877（8）°,V=1.659（3） nm3,Z=4,Dc=1.251 g?cm3,F（000）=656,μ（Mo Kα）=0.077 mm-1,R=0.050 5 and ωR=0.130 1.The ionic recognition ability and thermal stability of the compound were investigated.关键词：N,N′-diphenylthiourea;benzimidazole;1-［（phenylamino）-（phenylimine）］methylbenzimidazole;ion recognition;thermal stability
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- 1100
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发布时间： - 摘要：An ion chromatographic method with post-column deriviation and UV detection for the determination of iodate and bromate in cosmetics was developed and validated.The sample was purified with a guard-column IonPac AG11-HC(50 mm×4 mm),and separated on an analytical column IonPac AS11-HC(250 mm×4 mm) using KOH as an eluent with a self-regeneration suppressor.NaNO2 and KBr were used as the post-column deriviation solution.The analyte was quantitatively analysed by external standard and detected with a DAD detector.The results showed that the calibration curves were linear in the range of 2.0-1 000 mg/kg with correlation coefficients not less than 0.999 8.The spiked recoveries were in the range of 84%-99% with relative standard deviations(RSDs,n=3) less than 2%.With advantages of simplicity,good reproducibility and high sensitivity,the method was suitable for the determination of iodate and bromate in cosmetics.关键词：ion chromatography;post-column derivatization;cosmetics;iodate;bromate
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发布时间： - 摘要：An immunoaffinity column purification-high performance liquid chromatographic method was developed for the determination of vitamin B12 in milk powder.The sample was dissolved with phosphate buffer,and purified through the vitamin B12 immunity affinity column.After eluted with methanol,and concentrated,the target compound was directly measured on a Symmstry C18 column.The optimal conditions were as follows:column temperature:35 ℃,mobile phase:0.03 mol/L potassium dihydrogen phosphate（phosphate adjustable pH 3.0）-acetonitrile（85∶15）,flow rate:1.0 mL/min,detection wavelength:361 nm. Under the optimal conditions,the calibration curve was linear in the range of 20-300 μg/L ,with correlation coefficient（r） of 0.999 7 and a detection limit of 0.6 μg/kg.The spiked recoveries were in the range of 90%-96% with RSD of 1.1%-2.4%.Compared with the national standard method,the proposed method has the advantages of easy sample handling,high sensitivity,good reproducibility and short analysis time, and could meet the requirement for the determination of trace amounts of vitamin B12 in milk powder and infant formula.关键词：immunoaffinity column;milk powder;vitamin B12;HPLC
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