纳米磁珠-电化学适配体传感技术检测牛奶中氨苄青霉素

为满足牛奶中氨苄青霉素高效检测的需要,以纳米磁珠为载体,适配体与氨苄青霉素特异性结合为基础,构建氨苄青霉素电化学适配体传感器。采用碳二亚胺交联法制备修饰有氨苄青霉素的磁珠,该磁珠可与待测样中的氨苄青霉素共同竞争反应体系中的适配体和辣根过氧化物酶,随后利用磁性玻碳电极将上述磁珠吸附于电极检测表面进行电化学测定。最佳条件下,该传感器在1.0×10－12～1.0×10－8 mol/L浓度范围内传感器响应电流与氨苄青霉素浓度呈现良好的线性关系,检测限可达1.0×10－12 mol/L。采用该方法测定市售牛奶样品中的氨苄青霉素,精密度和回收率满意。     

基于量子点二抗偶联物的荧光免疫分析法测定牛奶中的氨苄青霉素

目的建立基于量子点二抗偶联物的荧光免疫分析法测定牛奶中的氨苄青霉素。方法采用共价偶联的方法将Qdot 655红色荧光量子点(quantum dots, QDs)与二抗偶联,利用制备好的QDs-二抗偶联物代替传统酶标二抗应用到检测牛奶中氨苄青霉素残留检测的荧光免疫分析方法中,并将该方法与酶联免疫吸附法(enzyme linked immunosorbent assay, ELISA)和高效液相色谱法(high performance liquid chromatography, HPLC)进行比较。结果该方法 50%抑制浓度(IC50)为8.3μg/L;检测限为2.5μg/L。空白牛奶加标回收率为94.0%～106.2%,变异系数为2.1%～9.2%。在实际样品的检测中,该方法与ELISA方法和HPLC方法测定的结果相比无显著差异(P0.05)。结论该方法准确、灵敏,适用于牛奶中氨苄青霉素残留的检测。     

表面等离子体共振技术在纺织等消费品检测中的应用

表面等离子体共振(SPR)生物传感技术是一种具有良好发展前景的新兴生物化学检测技术,具有灵敏度高、快速、无需标记等优点,广泛应用于材料化学、医药检测、环境监测和食品安全等领域。文章对SPR生物传感器进行了简要介绍,并着重对其在有毒有害残留检测中的应用进行了分析,最后对SPR生物传感技术在消费品检测领域的研究前景进行了展望。由于SPR技术检测过程方便快捷、灵敏度高,且只要更换不同的修饰特异性匹配芯片,一台仪器便可实现无机和有机类危害因子的筛查检测,因此SPR技术在消费品检测中有很好的发展前景。     

纺织品中双酚A的表面等离子体共振辅助检测方法

鉴于双酚Ａ（BPA）能够干扰生物的内分泌功能,引起各种生殖异常,威胁着婴幼儿的健康,甚至有致癌的危险等生物危害性,采用表面等离子体共振技术（SPR）对BPA 进行定性定量检测。从传感芯片的修饰、BPA-BSA溶液最佳质量浓度的确定、不同质量浓度BPA的响应情况以及纺织品中BPA的萃取等4个方面出发,探索了SPR技术检测纺织品中BPA的实用性。结果表明,BPA的SPR检测法具有检测速度快、对样品要求低、检测针对性强、检测灵敏度高等优点,适合检测领域的广泛应用,可应用于纺织品中双酚A含量的测定。     

光学免疫传感器的生物传感研究

正在研制的表面等离子体振子共振免疫传感器，用于测量血清中的抗原和抗体的迅速结合，它的共振灵敏度比光学技术的灵敏度高达７倍，所以它是一种新型的生物传感器技术、具的广泛的应用前景。     

基于局域表面等离子共振的比色法用于食品质量安全检测的研究进展

局域表面等离子体共振(LSPR)是表面等离子共振(SPR)中的一种特殊情况,是光线入射到金属纳米颗粒上引起的共振现象,可被用来实时跟踪生物分子之间在天然状态下的相互作用。这种方法对生物分子无任何损伤,且不需任何标记物。LSPR比色法灵敏度高、多色变化,可用于制作试纸条、试剂盒从而引起人们的广泛关注。本研究解释了LSPR的基本原理以及比色技术的概况,回顾了近5年基于LSPR的比色技术在食品安全方面的应用。最后,对基于LSPR生物传感器比色法的发展和应用以及研究领域所面临的挑战和未来的发展方向进行了讨论。     

生物素-亲和素增敏抑制型SPR等离子共振传感器检测牛奶中链霉素

针对牛奶中链霉素(STR)残留问题,开发一种基于生物素-亲和素系统(BAS)增敏及抑制型等离子共振(SPR)免疫传感器。方法:直接交联法获得的半抗原STR-OVA,通过活化酯法偶联生物素得到抗原BNHS-STR-OVA,与芯片上的链霉亲和素(SA)结合,绑定抗原。依据免疫抑制原理,STR与BNHS-STR-OVA共同竞争固定浓度的特异性抗体,依据不同浓度STR所得响应值,计算抑制率并绘制曲线,实现对食品中STR残留的准确、灵敏、快速分析。利用高效液相色谱串联质谱(HPLC-MS)检测该方法的准确性。结果:检测过程中抗原的固定量为6μg,抗体质量浓度为60 mg/mL。构建的抑制型免疫传感器的检出限(IC15)为0.37μg/L,灵敏度(IC50)为1.65μg/L。检测时长不超过10 min,芯片可重复使用90次。结论:研究所构建的BAS-SPR增敏、抑制型免疫传感器,方法简单,灵敏度高,检测时间短,成本低,可满足牛奶样品中STR高效检测的需求。     

光学免疫传感器的表面等离子体共振研究

论述了用于检测甲肝的表面等离子体供振免疫传感器的检测原理及方法，使用瞬息波技术的光学免疫传感器具有满足选择市场的要求，可以提供常规检测甲肝技术所不具备的一些优点，检测迅速，系统易于实现自动操作这种免疫传感器是基于检测血清中回旋体膜的抗体，使用了有关的抗原，它与有机体中有关的ＩｇＧ抗体发生反应，而此ＩｇＧ抗体存在于肝炎病人的血清中，用夹层表面等离子体振子共振方法，可以得到重复的结果，在键结合发生作用     

基于纳米银颗粒团聚反应的表面增强拉曼光谱法测定牛奶中三聚氰胺的含量

建立表面增强拉曼(surface-enhanced raman scattering,SERS)技术检测牛奶中三聚氰胺含量的方法。以金属钛板作为SERS衬底材料,采用50 nm银纳米颗粒作为基底,控制银溶胶与样品的体积比为1∶2,Na Cl和Na OH溶液的浓度为4 mol/L,通过便携式拉曼光谱仪采集样品的SERS信号。在质量浓度0. 2～10 mg/L的范围内,SERS强度随着牛奶中三聚氰胺浓度的增大而增强,线性相关系数R~2=0. 998,检测限为0. 08 mg/L。使用银纳米基底对1 mg/L加标样品平行测定20次,三聚氰胺特征峰强度的相对标准偏差为4. 34%。此法简单易行,重现性好、稳定性高,可实现对牛奶中三聚氰胺含量的快速检测,为食品中污染物的SERS检测提供了参考价值。     

表面等离子共振技术及其在食物过敏原检测中的应用

表面等离子共振(SPR)技术是研究分子间及生物大分子稳定性的一种有效的非标记生物物理技术,并已经成功应用于使用简单、快速、无需标记的生物传感器。本文主要介绍了SPR的基本原理,SPR生物传感器的应用特点及设备以及在食物过敏原检测中的应用。已有的研究结果表明,SPR生物传感器在检测牛奶、坚果、鸡蛋和鱼制品中的主要过敏原等方面,具有灵敏度高、准确度高、检测快捷等特点,将发展成为食物过敏原检测的重要技术手段。     

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.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

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.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.