氯唑西林可视化免疫亲和凝胶柱检测方法研究

为了建立氯唑西林(Cloxacillin,CLOX)可视化免疫亲和凝胶柱检测方法。实验采用活化酯法,将辣根过氧化物酶(HRP)与氯唑西林偶联,制得氯唑西林酶标抗原,并通过紫外光谱扫描鉴定表明CLOX酶标抗原合成成功。实验采用恒温振荡法,将溴化氰活化的琼脂糖凝胶分别与氯唑西林抗体、HRP抗体偶联制得氯唑西林抗体胶和HRP抗体胶,作为亲和凝胶柱的检测层与质控层。建立氯唑西林可视化免疫亲和凝胶柱分析方法,确定了该方法在酶标抗原的稀释倍数为4000、抗体胶稀释倍数为10、HRP胶稀释倍数为20、样品稀释液pH值为5.7、加样时间为60 s条件下,达到最佳工作状态。该方法检测限为25μg/L,特异性强,与哌拉西林、阿莫西林、氨苄青霉素、四环素、呋喃它酮、甲砜霉素、链霉素均无交叉反应,动物源食品实际样品中氯唑西林检出限为25μg/kg。该方法便捷、快速、可视化,适合作为高通量筛选氯唑西林的有效检测手段。     

呋喃它酮代谢物的可视化免疫亲和凝胶柱检测分析

为了建立一种用于检测动物源性食品中呋喃它酮代谢物(AMOZ)的可视化免疫亲和凝胶柱检测方法,利用对醛基苯甲酸(CPA)对AMOZ进行衍生处理得到衍生物CPAMOZ,制备CPAMOZ完全抗原,并通过免疫小鼠获取CPAMOZ多克隆抗体,使用间接ELISA法对抗体的效价及特异性进行测定。实验采用恒温振荡法将溴化氰活化的琼脂糖凝胶分别与CPAMOZ抗体、HRP抗体偶联制得CPAMOZ抗体胶和HRP抗体胶,作为亲和凝胶柱的检测层与质控层。建立AMOZ可视化免疫亲和凝胶柱分析方法,确定了该方法在酶标抗原的稀释倍数为5000、HRP胶稀释20倍、CPAMOZ抗体胶稀释15倍的条件下,达到最佳工作状态。实验结果表明CPAMOZ多克隆抗体效价为1:64000,IC_(50)值为2.19μg/L,具有良好的灵敏度及特异性。建立的AMOZ可视化免疫亲和凝胶检测柱方法检测限为4μg/L,动物源实际样品中AMOZ的检测限为2μg/kg。该方法快速便捷,符合我国高通量筛选食品中AMOZ的要求。     

葛根黄酮-金纳米粒子的绿色制备及其模拟酶催化活性研究

为制备绿色、环保且安全性高的金纳米粒子,采用离子液体-超声辅助法提取葛根黄酮,将得到的葛根黄酮作为还原剂和保护剂,一步绿色合成AuNPs,并以H₂O₂和3,3’,5,5’-四甲基联苯胺作为酶催化底物,对AuNPs模拟过氧化物酶进行活性验证。结果表明,制备的葛根黄酮-金纳米粒子具有模拟过氧化物酶的催化能力,在最适反应体系下,Au NPs模拟酶反应符合典型的Michaelis-Menten机制,以H₂O₂为底物时,K_m值为2.61 mmol/L;以3,3’,5,5’-四甲基联苯胺为底物时,K_m值为0.35 mmol/L,相比于天然辣根过氧化物酶,其与底物具有更强的亲和能力。研究所得的Au NPs在食品催化、生物医药和工业生产等领域将具有实际的应用价值。     

基于纳米金棒刻蚀的多色可视化传感器应用于乌头碱快速检测

目的基于纳米金棒刻蚀的多色可视化传感器快速检测乌头碱。方法采用H2O2-辣根过氧化物酶(horseradishperoxidase,HRP)-3,3’,5,5’-四甲基联苯胺(3,3’,5,5’-tetramethylbenzidine,TMB)体系的氧化产物TMB2+刻蚀纳米金棒,产生不同颜色的溶液,并将其与酶联免疫吸附测定法联用,构建一种酶联免疫多色可视化传感器应用于乌头碱快速半定量分析。结果在最优条件下,纳米金棒溶液的局域表面等离子体共振吸收峰的位移与乌头碱浓度在5~35ng/L范围内呈现较好的线性关系,检出限为1.67ng/L。结论该方法具有快速、选择性好、灵敏度高、裸眼可视化半定量等优点,对乌头碱的快速检测有一定的实际应用价值。     

微型氯霉素免疫亲和色谱柱的制备和测定

将氯霉素多克隆抗体与琼脂糖凝胶偶联,制备了对氯霉素有特异性吸附作用的微型氯霉素免疫亲和色谱柱,并对色谱柱进行了评价。该微型氯霉素免疫亲和色谱柱的动态柱容量为52720μg/L,富集极限可以达到100ng/L,对氯霉素的回收率达到98.5%以上,可以重复使用2次。该色谱柱可以有效消除基质的影响,提高检测的灵敏度,可应用于乳制品等食品中氯霉素残留的样品快速前处理。     

量子点标记免疫亲和凝胶柱快速检测动物组织中恩诺沙星

目的:建立一种检测动物组织中残留的兽药恩诺沙星(ENR)的量子点标记免疫亲和凝胶柱快速检测新方法。方法:将恩诺沙星特异性抗体偶联到溴化氢活化的琼脂糖凝胶上,制备抗体胶,将抗体胶装入标准的1mL SPE固相萃取柱制成恩诺沙星免疫亲和凝胶检测柱。采用混合酸酐法制备恩诺沙星包被抗原(ENR-OVA),采用活化酯法将ENR-OVA偶联到水溶性量子点(QDs)上制备荧光信号探针QDs-OVA-ENR。将待测样品和荧光信号探针QDs-OVA-ENR分别加入检测柱中,基于抗原抗体的竞争结合反应,样品中的恩诺沙星和荧光信号探针QDs-OVA-ENR竞争结合检测柱中抗体。通过目测检测柱体的荧光强弱,定性半定量检测恩诺沙星的含量。结果:该量子点标记恩诺沙星免疫亲和凝胶检测柱的检测限(LOD)为2μg/L,对食源性动物组织样品的检测限为20μg/kg。检测过程不超过5 min。结论:该方法操作简便,灵敏度高,检测时间短,结果易于判断,可满足食源性动物组织中恩诺沙星残留的现场快速检测要求。     

氯霉素高特异抗体的制备与纯化

目的自制免疫亲和层析柱,采用亲和层析法获取高纯度的抗氯霉素抗体并对其进行活性分析。方法采用硫酸铵分级沉淀法对抗体进行初步提取。然后选用3,3′-二氨丙基亚胺(DADPA)作为亲和凝胶与配基氯霉素之间的间隔臂,制备分离纯化抗氯霉素特异性IgG的亲和层析柱,对IgG粗品进行亲和层析纯化,并用ELISA法检测其活性。结果经饱和硫酸铵分级沉淀,可除去大部分的杂蛋白,较好实现对目标蛋白的初步分离;采用自制的免疫亲和层析柱,可获得高纯度的兔抗氯霉素抗体,检测其活性比纯化前提高了4倍,交叉反应结果显示抗体对CAP有高的特异性,对其他类似药物无反应活性。结论应用本试验所建立的方法可得到高纯度的抗氯霉素抗体,为氯霉素的免疫检测奠定了基础。     

恩诺沙星可视化凝胶柱快速免疫检测方法研究

建立一种动物源性食品中兽药恩诺沙星可视化凝胶柱快速免疫检测新方法。采用活化酯法制备恩诺沙星与辣根过氧化氢酶(HRP)的偶联物作为酶标抗原。整个检测在一个标准的1 m L SPE固相萃取柱中进行,柱中包含两层:一个结合了恩诺沙星特异性抗体的凝胶检测层和一个结合了HRP抗体的凝胶质控层。将样品提取液与酶标抗原预混合后加入到检测柱中,基于抗原抗体的竞争结合反应和辣根过氧化物酶的酶促反应,根据检测柱的检测层颜色的深浅和有无来定性半定量检测恩诺沙星的含量。该凝胶检测柱的检测限为5μg/L,整个检测过程可以在10 min内完成,猪肉、牛肉、鸡肉、鱼肉、虾肉和牛奶等动物源性食品中恩诺沙星检测限为100μg/kg。该方法具有准确、灵敏、特异性好、操作简便快速、成本低等优势,适合动物源性食品中恩诺沙星残留的快速筛查。     

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。     

呋喃它酮代谢物可视化凝胶柱快速免疫检测方法研究

本研究建立了兽药呋喃它酮代谢物(Furaltadone metabolites,AMOZ)的免疫亲和凝胶柱检测新方法,并用于动物源性食品中呋喃它酮代谢物残留的可视化快速检测。整个检测在一个标准的1 mL固相萃取(SPE)柱中进行,柱中包含两层:一个结合了呋喃它酮代谢物特异性抗体的凝胶检测层和一个结合了辣根过氧化物酶(HRP)抗体的凝胶质控层。将样品提取液与酶标抗原预混合后加入到检测柱中,基于抗原抗体的竞争结合反应和辣根过氧化物酶的酶促反应,根据检测柱的检测层颜色的深浅和有无来定性,半定量检测呋喃它酮代谢物的含量。整个检测过程可以在10 min内完成,该凝胶检测柱的检测限为20μg/L;牛肉、鲷鱼、鸡肉、虾肉、猪肉、鱿鱼、鸡肝和黄花鱼等动物源性食品中呋喃它酮代谢物的检测限为3μg/kg。该方法准确度高、特异性好、检测步骤简单,适用于大量样品中呋喃它酮代谢物残留的快速检测。     

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.     

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.     

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.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.     

Analysis on Economic Indicators from 62 Enterprises in Printing Machinery Industry in Q1 2014

Operation of printing machine industry was still unsatisfactory in the first quarter of 2014.Analysis on operation of printing machine industry.a.Market demand was not strong;sales of product undulated and declined.According to the statistics,the total industrial output value fell by 19.28% in the first quarter of 2014 than the average quarter value in 2013; industrial added value decreased by 4.16%; sales revenue dropped by 22.83%. h. Business operation of enterprises was in poor condition. c. R＆D of new products is an important transformation guarantee for enterprises. d. To take self explore new ways upgrading advantages,and explore new ways.