基于核酸适配体的镉离子可视化检测方法

利用适配体对镉离子的特异性识别作用,以镉离子适配体及互补链为生物识别单元,建立基于核酸适配体的镉离子可视化检测方法,实现对自来水中镉离子痕量检测。该方法将镉离子适配体固定在微孔板上,再与适配体互补链及-辣根过氧化物酶(HRP)复合物进行竞争性结合,通过HRP对底物的催化水解反应引起450nm处特征峰的变化来定量检测镉离子。结果表明:该检测体系在0.1~5.0ng/mL时具有线性关系(R~2=0.995 8),检测限低至0.5ng/mL。该方法选择性良好、操作简单、灵敏度高,并且具有较好的实用性,可用于食品安全分析和环境监测中金属离子镉的检测。     

竞争性酶联适配体可视化检测玉米赤霉烯酮

建立一种基于竞争性酶联适配体检测食品中玉米赤霉烯酮的可视化分析方法.将生物素标记的玉米赤霉烯酮适配体通过生物素-亲和素连接固定在微孔板上,玉米赤霉烯酮适配体的互补链(cDNA)与辣根过氧化物酶(HRP)连接形成cDNA-HRP信号探针,cDNA-HRP信号探针和靶标竞争与适配体结合,加入TMB显色液和硫酸终止液后,即可...     

基于上转换纳米粒子与金纳米粒子构建荧光共振能量转移体系检测双酚A方法研究

制备了粒径为13nm的金纳米粒子,在其表面修饰双酚A(BPA)适配体作为能量受体探针;并利用聚丙烯酸(PAA)包覆油溶性的上转换荧光纳米材料(UCNPs)制备水溶性的UCNPs,在其表面修饰适配体互补链形成功能化UCNPs作为能量供体,构建了基于FRET原理的BPA生物传感检测平台。结果表明:该检测体系在1×10~(-9)～1×10~(-3) mol/L时具有良好的线性关系(R~2=0.992 3),检出限低至1×10~(-10) mol/L。     

核酸适配体-纳米金可视化检测盐酸克伦特罗

建立了一种基于核酸适配体识别-纳米金显色的盐酸克伦特罗可视化检测方法。通过合成纳米金、适配体、适配体互补链以及适配体-纳米金探针和互补链-纳米金探针,利用纳米金的变色效应,构建了盐酸克伦特罗的简单、快速、高灵敏度检测方法。当待测物中含有目标物时,适配体与目标物结合,纳米金呈现游离状态,在一定的盐浓度下,纳米颗粒发生聚集,纳米金颜色发生变化;当待测物中不含目标物时,适配体与适配体互补链互补杂交,形成稳定的网络结构,溶液颜色不发生变化。分别对适配体、互补链与纳米金连接的陈化盐浓度、适配体与互补链浓度、显色体系盐浓度等参数进行了优化。在优化的条件下,盐酸克伦特罗在1～1000 ng/mL浓度范围内,呈现良好的线性关系,回归方程为y=0.023x+0.362(R2=0.991),最低检测限为1ng/m L。对猪肝实际样品的加标回收率为83.5%～101.8%。该方法简单、准确、可靠,可用于实际样品的检测分析。     

适配体增强金纳米粒子类过氧化物酶活性快速检测鸡蛋中的恩诺沙星

目的 利用核酸适配体增强金纳米粒子类过氧化物酶(peroxidase,POD)活性,建立了一种快速检测鸡蛋中恩诺沙星的方法。方法 金纳米粒子具有类POD活性,能催化H₂O₂氧化3,3’-5,5’四甲基联苯胺(3,3’-5,5’tetramethylbenzidine, TMB)反应,加入核酸适配体后,适配体通过Au-N键吸附于金纳米粒子表面,使催化活性增强;进一步加入靶标物恩诺沙星后,核酸适配体与靶标物特异性结合而脱离金纳米粒子表面,使催化活性减弱。基于此建立了恩诺沙星比色检测方法,优化了反应条件,并将其用于鸡蛋样品检测中。结果 在核酸适配体浓度为10 nmol/L, TMB浓度为0.3 mmol/L,显色反应时间为20 min时,反应体系的吸光度变化随恩诺沙星浓度在5～150μmol/L范围内具有良好的线性关系,检出限为1.98μmol/L。该方法具有良好的选择性和抗干扰能力,将此法用于鸡蛋中的恩诺沙星的检测,加标回收率为92.67%～109.04%。结论 该方法简便快速,为鸡蛋中恩诺沙星检测提供了一种新的尝试方法。     

基于核酸适配体识别-时间分辨荧光共振能量转移检测牛奶中培氟沙星兽药残留

培氟沙星(pefloxacin,PEF)广泛用于畜禽疾病的预防和治疗,常造成兽药残留,影响人体健康。因此,有必要对其构建有效快速的检测方法。实验采用溶剂热法合成具有时间分辨特性的荧光纳米材料NaYF₄∶Ce/Tb,并基于分子对接辅助设计PEF适配体的互补链。纳米金与发光纳米材料分别修饰在适配体、互补链上,通过碱基互补配对诱导2种纳米材料间发生时间分辨荧光共振能量转移(time-resolved fluorescence resonance energy transfer,TR-FRET),基于此原理构建基于生物传感PEF的新型检测方法。在最佳条件下,测得PEF的时间分辨荧光强度在质量浓度0.2~20μg/kg呈良好的线性关系(y=1567.3x+3956.3,R²=0.9742),检测限为0.15μg/kg,测得牛奶中兽药残留加标回收率为73.81%~99.86%,表明该方法可用于实际食品样品中PEF的检测。     

基于酶联适配体的四环素检测方法研究

通过Mannich法偶联辣根过氧化物酶(HRP)和四环素(tetracycline,TC)分子制备酶标记物,采用棋盘滴定法确定链霉亲和素(streptavidin,SA)的包被浓度为8μg/mL,适配体稀释浓度为20 nmol/L。通过单因素实验优化了检测条件,碳酸盐缓冲液(CB,0.05 mol/L,pH 9.6)为包被液,适配体稀释液选择含有5 mmol/L Mg2+的磷酸缓冲液PBS,TC-HRP稀释度为1:50,标准品稀释液为PBS溶液,适配体孵育1 h,最终建立了四环素酶联适配体检测(enzyme-linked aptamer assay,ELAA)方法。该法半抑制浓度(IC50)为0.705μg/mL,检测限(LOD)为2.5 ng/mL,与其结构类似物(多西环素、土霉素、金霉素)测试中,发现除与金霉素稍有交叉反应(25.9%)外,与其他药物基本没有明显交叉反应。本研究所建立的直接竞争酶联适配体检测方法特异性强、灵敏度高,能够满足四环素定量分析要求,适用于食品中四环素的快速检测。     

基于核酸适配体的电化学法检测铅离子

目的 建立基于核酸适配体的铅离子电化学检测方法。方法 铅离子适配体能够与辣根过氧化物酶(horseradish peroxidase, HRP)标记的铅离子适配体互补单链DNA形成稳定的结构, 当向溶液中加入铅离子时, 铅离子适配体与铅离子结合, 导致电极上固定的HRP减少。HRP能够催化溶液中双氧水(H2O2)和对苯二酚(hydroquinone quinol, HQ)发生氧化还原反应产生电化学信号。通过电化学信号的改变实现对铅离子的定量检测。结果 在铅离子浓度为1.0×10?4~1.0×10?1 g/L时, 电流与铅离子浓度呈线性关系为I(μA)=?17.678LogC/(g/L)+ 1.331(r2=0.995), 检测限为9.0×10?5 g/L。结论 该方法具有操作简单、灵敏度高、特异性好等优点, 可用于食品安全检测和分析中铅离子的测定。     

动物食品中去甲基睾丸酮的纳米增强酶联免疫分析方法

作者通过辣根过氧化物酶标记抗体(HRP-IgG)蛋白分子固定在金纳米粒子(GNP)表面的方法,制备得到一种高活性的酶-金纳米复合物(HRP-IgG-GNP)。将该HRP-IgG-GNP应用于酶联免疫分析(ELISA)方法中,针对去甲基睾酮(NT),建立了一种高灵敏的纳米增强ELISA方法。该方法的检测灵敏度达到0.01 ng/mL,线性范围为0.03~10 ng/mL。与传统ELISA方法相比,该方法的灵敏度提高了10倍。该纳米增强ELISA方法有望开发高灵敏免疫分析方法中获得广泛应用。     

基于纳米材料的电化学适配体传感器在食品重金属检测中的研究进展

重金属是食品和环境中的一类剧毒污染物,易引起食源性疾病,对人体造成不可逆损伤。传统的检测方法耗时长、成本高,因此迫切需要开发食品中重金属的快速检测技术。基于纳米材料的电化学适配体传感器具有快速、高灵敏度、特异性强等优点,在重金属快速检测领域具有广阔的应用前景。本文总结了金属纳米材料（如金纳米粒子）、金属氧化物（Fe₃O₄纳米颗粒）、碳纳米材料（如碳纳米管、石墨烯）等材料的性质,并对基于纳米材料的电化学适配体传感器在重金属（主要是Pb2+、Hg2+、As3+、Cd2+）检测中的应用进行了综述,以期为重金属检测相关研究提供参考和启发。     

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