罗丹明B强吸附分子印迹材料的制备及吸附性能评价

目的制备一种对罗丹明B具有特异性和强吸附性能的分子印迹材料。方法采用沉淀聚合法合成罗丹明B分子印迹聚合物(molecularly imprinted polymer,MIP),对分子印迹材料的动力学吸附、等温饱和吸附、选择性吸附及其对果汁样品中罗丹明B的吸附能力进行评价。结果以丙烯酰胺为功能单体制备的印迹聚合物的印迹效率(a=QMIP/QNIP)可达3。动力学吸附实验表明,MIP对罗丹明B的吸附可在15min内完成。等温吸附性能评价得出饱和吸附量约为170μg/mg。罗丹明B分子印迹聚合物对几种红色色素的吸附量的顺序为:罗丹明B诱惑红赤藓红苋菜红胭脂红。罗丹明B分子印迹聚合物对于添加到果汁中的罗丹明B可以很好地吸附而对其他成分的吸附较小。结论罗丹明B分子印迹聚合物对罗丹明B具有明显的特异性吸附性能,而且具有较强的吸附能力,是一种具有潜力的用于罗丹明B分析的固相萃取材料。     

双酚A印迹聚合微球制备、识别机理及固相萃取研究

以双酚A(BPA)为模版分子,4-VP为功能单体,Trim为交联剂,采用沉淀聚合法合成BPA分子印迹聚合微球(MIPs)。通过紫外和红外光谱考察BPA与4-VP相作用机理,扫描电镜(SEM)观察MIPs的表观形态;结果表明BPA和4-VP之间形成了氢键并且以1:2的比例相结合,MIPs表面光滑呈球状。吸附实验显示MIPs具有较高的特异性,吸附能力远高于非分子印迹聚合物(NIPs)。对吸附曲线进行Scatchard分析,在MIPs上形成了均匀的BPA吸附位点,其最大表观吸附量(Qmax)和平衡离解常数(Kd)分别为28.83μmol/g和0.3112μmol/L。固相萃取(SPE)分析表明MIPs对BPA具有较高选择性和吸附容量,可以用于分离、富集和检测复杂食品样品中的BPA。     

植酸分子印迹聚合物的制备、表征及吸附性能

以植酸为模板分子,甲基丙烯酸(MAA)为功能单体,N,N'-乙烯基丙烯酰胺(EBA)为交联剂,过硫酸铵为引发剂,采用本体聚合法制备对植酸具有高特异选择性的植酸分子印迹聚合物(MIPs)。通过扫描电镜观察了分子印迹聚合物表面的结构,利用红外光谱进一步对其化学结构进行表征。通过动态吸附、静态吸附和选择性吸附考察了其吸附性能。研究表明植酸分子印迹聚合物对植酸的吸附高于对肌醇的吸附,植酸在印迹聚合物中的印迹因子为1.70,而与植酸结构相似物肌醇的印迹因子为1.46。解吸80 min,MIPs解吸达到稳定,解吸率达到89.59%。植酸分子印迹聚合物对植酸的吸附特异性强,对植酸的吸附量为21.38μmol·g~(-1),解吸效果好,进行吸附-解吸附循环5次后,植酸印迹聚合物的性能稳定,对植酸吸附容量为65.62μmol·g~(-1),是第一次吸附容量的90.00%,可重复使用。     

分子印迹技术在食品样品安全分析中的应用

食品基质复杂多样,食品中相关物质检测的准确性很大程度上依赖于食品的前处理,如何通过食品的前处理提高方法的选择性和特异性是食品检测的关键。分子印迹聚合物(molecularly imprinted polymers,MIPs)是一种可特异性识别靶标物质的聚合物,由模板分子和功能单体形成的络合物与致孔剂共聚合,再去除模板,形成与目标物在形状、大小、官能团和空间排列上互补的空间结构和结合位点,由于其亲和力和选择性较强,目前已经广泛应用于食品样品的前处理过程中。本文介绍了MIPs的主要制备方法,综述了基于分子印迹技术的固相萃取、固相微萃取、搅拌棒吸附萃取和基质固相分散萃取在食品样品前处理中的最新应用进展,总结了目前MIPs在食品样品前处理过程中存在的问题以及未来的发展方向和趋势。     

香兰素分子印迹微球的制备及识别机理

以香兰素(Van)为模板、甲基丙烯酸(MAA)为功能单体、偶氮二异丁腈(AIBN)为引发剂和乙烯二醇二甲基丙烯酸酯(EDMA)为交联剂,采用沉淀聚合法合成一种新型的对Van有特异识别功能的分子印迹聚合物微球(MIPs)。通过UV、傅里叶变换红外光谱仪(FT-IR)和1H NMR光谱法研究模板与功能单体之间的相互作用和识别机理,采用扫描电镜(SEM)考察MIPs表面形态,通过平衡和等温吸附实验对MIPs和非分子印迹微球(NIPs)吸附性能进行研究。结果表明:MAA与Van之间通过氢键相互作用,MIPs具有表面光滑的规则球状结构,MIPs对Van的吸附和识别能力远高于NIPs,并且在120min后达到吸附平衡状态,Scatchard分析表明在MIPs上形成了均匀的对Van有特异性的结合位点,最大表观吸附量Qmax和平衡离解常数Kd分别为7.357μmol/g和4.243×10-5mol/L;选择性分离、分子印迹固相萃取(MIP-SPE)和HPLC实验分析表明,MIPs对Van具有很好的分离和富集能力。     

花椒麻味物质分子印迹聚合物的制备及吸附特性

为实现对花椒麻味物质经济高效的纯化制备,本实验采用分子印迹技术,以甲基丙烯酸为功能单体,花椒麻味物质为模板分子,合成对花椒麻味物质具有特异性识别和吸附能力的分子印迹聚合物(molecularly imprinted polymers,MIPs),并用MIPs制成固相萃取柱用于分离纯化花椒油树脂中的花椒麻味物质。吸附动力学实验结果显示,MIPs与花椒麻味物质接触约12 h后就达到吸附平衡,对花椒麻味物质识别因子α达到3.05;等温吸附实验表明,MIPs对花椒麻味物质的吸附量高于空白聚合物,在吸附过程中模板分子花椒麻味物质与MIPs形成两种结合位点,两种结合位点的解离常数分别为1.172×10~(-2) mg/m L和3.585×10~(-2) mg/m L,对花椒麻味物质最大表观吸附量分别为11.133 mg/g和15.802 mg/g;固相萃取实验表明,该固相萃取柱可以分离出相对纯度为94.09%的花椒麻味物质。     

分子印迹固相萃取技术对六堡茶中表儿茶素的分离特性

以表儿茶素为模板分子,丙烯酰胺为功能单体,偶氮二异丁腈作为引发剂,乙二醇二甲基丙烯酸酯为交联剂,通过原位聚合法制备分子印迹聚合物。首先考察不同模板分子、功能单体、交联剂比例条件下表儿茶素分子印迹聚合物的特异性吸附能力。结果表明表儿茶素与丙烯酰胺、乙二醇二甲基丙烯酸酯物质的量比为1∶6∶40时,分子印迹聚合物的吸附效果最佳,其模板分子回收率KMIPs为84.62%,特异性识别因子Q为4.55;然后利用扫描电子显微镜和红外光谱技术对制备的印迹聚合材料进行表征;最后在毛细管电泳最优条件下对加载过固相萃取柱的过柱液与洗脱液进行检测,建立分子印迹固相萃取-毛细管电泳联用检测表儿茶素的方法。实验结果表明,分子印迹聚合物成功聚合,形貌良好且具有专一吸附特性。该方法适用于六堡茶中表儿茶素的检测。     

6-氨基青霉素烷酸分子印迹固相萃取柱在牛乳青霉素药物检测中的应用

用实验室制备的分子印迹固相萃取柱完成市售牛乳样品中青霉素类药物的提取分离。以青霉素中间体6-氨基青霉烷酸(6-Aminopenicillanic acid,6-APA)为虚拟模板分子,甲酸作为致孔剂,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,合成6-APA分子印迹聚合物(molecular imprinted polymers,MIPs),并对制备条件进行了优化,确定最佳的制备条件是模板分子∶功能单体∶交联剂(摩尔比)=1∶5∶30。采用选择性吸附试验比较青霉素类药物与恩诺沙星在该MIPs的吸附情况,结果表明:MIPs对青霉素类药物及其中间体具有特异性吸附;通过红外光谱和扫描电镜对MIPs结构和形貌进行表征,红外光谱分析可知,MIPs内部具有键合氢键的位点,观察MIPs扫描电镜图发现MIPs表面具有大量孔穴。使用该MIPs装填的固相萃取柱对牛乳样品进行预处理,并采用高效液相色谱进行检测,结果显示有牛乳样品中含有较高浓度6-APA;用空白样品添加不同浓度水平的3种青霉素类药物及6-APA混合溶液进行加标回收率实验,加标回收率为83.5%~87.3%,相对标准偏差(RSDs)为1.03%~7.35%。6-APA分子印迹固相萃取柱在复杂基质如动物源食品、水体、土壤样品的检测中具有广阔前景。     

芦丁分子印迹聚合物的制备及其吸附性能的研究

以芦丁为模板分子,以α-甲基丙烯酸(MAA)和丙烯酰胺(AM)为功能单体,乙二醇二甲基丙烯酸酯(EGDMA)为交联剂,偶氮二异丁腈(AIBN)为引发剂,利用分子印迹技术在甲醇/水(V/V,1/4)溶剂中合成了芦丁分子印迹聚合物(MIPs),研究了不同功能单体及其用量和不同交联剂用量的聚合体系组成对印迹聚合物吸附特性的影响。对最佳比例制备的MIPs进行了吸附等温实验和Scatchard分析,其结合位点的离解常数Kd分别为105.26mg.L-1和1250mg.L-1,饱和吸附量Qmax分别为18.02mg.g-1和73.50mg.g-1。并利用红外光谱(IR)对分子印迹聚合物进行了表征。     

白藜芦醇分子印迹聚合物的应用及性能研究

采用分子印迹技术以白黎芦醇为模板分子,选择丙烯酰胺作为白藜芦醇印迹聚合物的功能单体,氯仿和四氢呋喃的混合溶液作为印迹聚合物合成溶剂,制备了白黎芦醇分子印迹聚合物,考察了分子印迹聚合物的吸附性能、选择性能以及固相萃取性能。优化分子印迹固相萃取的萃取条件,选择30%(体积分数)的乙醇-水溶液5 m L作为上样溶液,选择40%(体积分数)的乙醇-水溶液作为淋洗液、80%(体积分数)的乙醇-水溶液作为洗脱液。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the