甲烷氧化菌素-纳米金修饰金电极溶出伏安法对Cu2＋的检测

利用甲烷氧化菌素能捕捉环境中Cu2＋的特性,以及纳米金放大电信号的作用,制备甲烷氧化菌素功能化纳米金,通过将其修饰金电极的溶出伏安法对Cu2＋进行特异性检测。在优化条件下,峰电流与Cu2＋浓度的对数在10 nmol/L～100 μmol/L范围内线性关系良好,相关系数为0.960 09,检出限为1.15 nmol/L（信噪比3）。结果证明,本研究所建立的电化学新方法具有较高的检测灵敏度和稳定性,可以为未来食品中Cu2＋的检测提供一定理论依据。     

基于纳米金标记-适配体识别的伏马菌素B_1检测新方法

基于核酸适配体识别和纳米金变色效应构建了伏马菌素B1(FB1)的可视化检测新方法。实验以纳米金为载体,首先在纳米金表面组装巯基化的适配体互补短链DNA1/FB1-适配体复合物;当加入目标物时,适配体链与目标物结合,与互补短链DNA1发生解离;此时再加入纳米金标记的与适配体互补短链1互补的短链DNA2,二者杂交可导致纳米金粒子的聚集而使溶液颜色发生变化,进而实现目标物的可视化检测。通过条件优化,有效避免了由于盐浓度过高使纳米金发生聚集所产生的误差。同时在纳米金与短链DNA孵化时加入表面活性剂十二烷基硫酸钠(SDS),使NaCl浓度达到了500 mmol/L而纳米金颜色仍不发生改变,打破了以往熟化NaCl浓度100 mmol/L就使纳米金颜色发生变化的界限,使附着在纳米金上的DNA量扩大了3倍。方法检测线性范围为125～1 500 ng/L,检测限为125 ng/L。该方法已成功应用于啤酒中FB1的检测。     

基于纳米金标记的金黄色葡萄球菌可视化检测方法研究

目的 以纳米金为载体, 对金黄色葡萄球菌进行可视化检测。方法 将与金黄色葡萄球菌目标序列互补的DNA 1和DNA 2连接到纳米金上, 当体系中出现金黄色葡萄球菌目标序列时, 两条短链DNA就会与目标序列杂交, 使纳米金之间的距离拉近, 从而使纳米金发生团聚, 导致纳米金的颜色从酒红色变为蓝色。由于金黄色葡萄球菌目标序列浓度的不同, 从而引起纳米金之间团聚的程度不同, 纳米金就会相应的呈现出不同的颜色变化, 这样就可达到可视化检测的目的。结果 在最优实验条件下, 本方法在检测金黄色葡萄球菌目标序列时, 浓度在1~1000 pmol/L范围内呈现良好的线性关系, 检出限为0.5 pmol/L; 检测金黄色葡萄球菌时, 线性范围为30~9800 CFU/mL, 检出限为25 CFU/mL。结论 通过特异性和加标回收实验, 证明本方法可以用于实际样品的检测。     

功能化纳米金修饰电极检测食品中H2O2的残留量

通过电沉积法修饰功能化纳米金修饰电极,实现过氧化氢的电化学检测。通过研究修饰电极在过氧化氢中的电化学行为,得到检测过氧化氢的较优条件并建立检测过氧化氢标准曲线。得到优化条件为:功能化物质半胱氨酸/巯基乙胺、纳米金粒径15 nm、功能化物质浓度0.05 mol/L、扫描速度110 mV/s、检测过氧化氢时缓冲溶液pH为6.0等。过氧化氢标准曲线线性关系良好,相关系数r为0.997,检出限为0.129 μmol/L,定量限为0.431 μmol/L,具有良好的重现性和稳定性,精密度高,对葡萄糖、甘氨酸、抗坏血酸、钾盐、钠盐等具有较强的抗干扰能力,该修饰电极检测过氧化氢性能良好,在实际样品检测中回收率为92.1%~95.6%,RSD在2.26%~4.52%,可用于实际样品中过氧化氢的测定。     

基于巯基磷酸和巯基环糊精双修饰纳米金的修饰电极测定微囊藻毒素的研究

为了快速灵敏的检测微囊藻毒素(MC)的含量,本研究根据微囊藻毒素LR亚型(MC-LR)的结构特点对纳米金进行了巯基β-环糊精和巯基磷酸的双修饰,建立了一种基于双修饰纳米金材料的微分脉冲伏安电化学分析方法检测MC。结果表明双修饰的纳米金对MC具有良好的吸附性能,其吸附量达到2.125μg/m L,静态分布系数为5.67。利用电聚合中性红修饰的玻碳电极表面正电荷吸附双修饰纳米金材料制备电化学传感器,测定MC,结果表明该电极对MC-LR的线性范围为26 nmol/L~213μmol/L,检测限为(3σ/S)19 nmol/L,且具有良好的抗干扰能力。     

基于纳米金/多壁碳纳米管修饰电极的叔丁基羟基茴香醚检测

本试验利用纳米金/多壁碳纳米管复合物(Au/MWCNTs)修饰硼掺杂金刚石电极(BDD),对抗氧化剂叔丁基羟基茴香醚(BHA)进行检测.研究了BHA在裸电极和修饰电极上的电化学行为.结果表明,经Au/MWCNTs修饰后,BHA产生的峰电流由1.096μA增加到2.036 μA,提高了85.77％;峰电位从0.704 V负移至0.6V.在5～ 200μmol/L范围内,Au/MWCNTs-BDD电极上得到的检出限为5.70 μmol/L,低于BDD电极上得到的16.72μmol/L.采用该方法检测植物油中BHA的含量,回收率为99.2％ ～ 103.2％.     

绿茶提取液制备金纳米粒子及其在VC比色分析中的应用

以绿茶提取液为还原剂和保护剂,简单快速绿色制备金纳米粒子。与传统方法制备的金纳米粒子相比,绿茶提取液制备的金纳米粒子耐高盐耐酸碱,具有更好的稳定性。将金纳米粒子与VC和AgNO3混合,VC还原AgNO3产生银单质覆盖在金纳米粒子表面,形成金银核壳纳米粒子,导致溶液颜色及波长410 nm处吸光度变化,实现VC的定性及定量分析,基于此将金纳米粒子用于VC的比色分析。最优条件下,VC质量浓度2 mg/L时裸眼观察到溶液颜色由浅粉变为淡黄色;结合紫外-可见光度计检测,波长410 nm处吸光度与VC质量浓度在0.4～120 mg/L范围内呈现良好的线性关系,检出限为0.14 mg/L。将此方法用于VC药片和市售饮料中VC的分析,加标回收率在92.2%～115.0%之间。     

二硫化钼负载纳米金粒子修饰电极测定酱油中曲酸

目的 建立二硫化钼负载纳米金粒子(MoS2/gold nanoparticles, MoS2/AuNPs)修饰电极快速测定酱油中曲酸的方法。方法 采用柠檬酸钠还原氯金酸的方法制备纳米金颗粒, 采用恒电位沉积法制备二硫化钼负载纳米金粒子的修饰电极。研究曲酸在不同修饰电极上的电化学行为, 探讨缓冲溶液类型、pH、MoS2用量和沉积时间对曲酸电化学行为的影响。结果 在5~500 μmol/L范围内, 曲酸浓度与峰电流呈现良好的线性关系, 回归方程为ipa (μA)=0.00952C (μmol/L)-0.21898, r2=0.99345。检出限为3.9 μmol/L, 回收率为97.2%~105.5%, 相对标准偏差小于8.0%。结论 本方法所构建的修饰电极具有较好的抗干扰性、重现性和稳定性, 适用于酱油样品中曲酸的分析。     

金纳米粒子-DNA折纸组装体的构建及对17β-雌二醇的检测

目的 为实现DNA折纸上金纳米粒子的高效组装和雌二醇的可视化检测,本研究将正丁醇法和“一步退火”法结合用于金纳米粒子快速修饰和在DNA折纸上高效组装,并将DNA折纸与适配体和金纳米粒子结合用AFM可视化检测雌二醇。方法 巯基修饰的DNA与金纳米粒子混合物与正丁醇接触,快速除去水分, 通过Au-S键共价结合形成致密的球形核酸。引入一种自下而上可编程DNA自组装的方法-DNA折纸术(DNA Origami), 利用其精确的定位功能, 将DNA折纸单链和球形核酸混合, 一步退火形成DNA折纸-金纳米粒子组装体结构。进一步将DNA折纸与适配体结合, 金纳米粒子作为信号探针, 利用原子力显微镜(Atomic Force Microscope, AFM) 进行17β-雌二醇(E2)的可视化检测。结果 通过加盐实验和电位表征, 表明正丁醇法能够在几秒内完成金纳米粒子的表面功能化, 节省了实验时间; 通过AFM表征, 表明“一步退火”可以实现金纳米粒子在DNA折纸上的高效组装, 并且“一步退火”的组装效果远远好于“二步退火”。生物传感器可以通过AFM直观地检测50 ng/mL的E2。结论 在本研究中,利用正丁醇法合成的球形核酸经过一步退火实现了在DNA折纸上的高效组装,其次,提出了基于DNA折纸可视化检测E2的纳米生物传感新方法。     

基于Au@Co-MOF/GCE传感器检测阿魏酸的研究

合成了钴金属有机骨架(Cobalt metal organic skeleton,Co-MOF)纳米材料并在此基础上负载金纳米粒子(Gold nanomaterials,Au)制备了一种新型的金@钴金属有机骨架(Gold@Cobalt metal organic skeleton Nanocomposites,Au@Co-MOF)纳米复合材料。以Au@Co-MOF为修饰材料,采用玻碳电极(Glassy carbon electrode,GCE)为工作电极,构建Au@Co-MOF/GCE。通过对磷酸盐缓冲溶液(Phosphate buffer solution,PBS)和Au@Co-MOF的优化,确定了Au@Co-MOF/GCE的最佳工作条件。研究发现,阿魏酸浓度与其氧化峰电流分别在0.05～4 μmol/L和4～450 μmol/L范围内呈现线性关系,检出限(S/N=3)为0.0089 μmol/L,明显优于其它传感器且Au@Co-MOF/GCE抗干扰能力、重复性和稳定性良好,30 d后其对阿魏酸的检测结果仍可达到最初的95.04%,连续8次检测结果的RSD为3.05%。Au@Co-M...     

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.     

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     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press