金磁微粒模拟酶检测食品中的葡萄糖

采用水热法制备Fe3O4纳米粒子,并通过对其表面氨基化与金纳米粒子自组装方法构建金磁微粒（Fe3O4@Au）,并表征其性能。在其具有模拟过氧化物酶活性的基础上结合葡萄糖在葡萄糖氧化酶作用下产生H2O2,并与过氧化物酶底物二胺盐产生显色反应的原理,建立可视化检测葡萄糖含量的简便方法,并优化葡萄糖检测体系,并对其选择性和回收率进行分析。结果表明,氨基化的Fe3O4纳米粒子可以有效固载金纳米粒子,Fe3O4@Au饱和磁化强度为43 emu/g。检测体系最优工艺组合为：Fe3O4@Au混悬液质量浓度0.15 g/mL、温度70 ℃、时间50 min。在优化条件下,葡萄糖在1～20 mmol/L范围内具有良好的线性关系,线性相关系数R2为0.992 5,检出限为2.45 μmol/L,加标回收率在96%～104%之间,并具有良好的选择性和稳定性。本研究将拓宽纳米材料模拟酶在食品检测的应用并为葡萄糖检测方法的改进提供一种新的思路。     

基于氯化血红素-无花果蛋白酶复合物比色检测抗坏血酸的研究

目的 利用氯化血红素-无花果蛋白酶复合物(hemin-ficin)模拟过氧化物酶活性构建抗坏血酸快速比色检测体系.方法 通过单因素实验优化H2O2浓度、hemin-ficin浓度和孵育时间3个因素对hemin-ficin复合物比色检测体系的影响,利用正交实验设计优化获得最佳检测条件.同时对体系的灵敏度、抗干扰性和稳定性...     

基于Fe3O4@Au微粒电化学检测邻苯二酚的研究

基于复合纳米粒子具有过氧化物模拟酶活性的特点,采用自组装的方法将Fe3O4磁性微粒与金纳米粒子(AuNPs)结合,制备出金磁微粒(Fe3O4@Au)复合纳米粒子.探索其模拟过氧化物酶的活性,并构建出具有高灵敏度和选择性的检测邻苯二酚的无酶增强型电化学传感器.结果表明,影响Fe3O4@Au模拟酶催化效率的因素主次顺序为扫...     

基于金磁微粒模拟酶电化学增强体系检测抗坏血酸

通过自组装方法构建金磁微粒(Fe3O4@Au)复合纳米粒子,并表征其理化性能。基于复合纳米粒子的过氧化物模拟酶活性,构建出具有高灵敏度和选择性检测抗坏血酸的无酶增强型电化学传感器。采用循环伏安法对抗坏血酸进行测定,并优化电化学检测体系。结果表明,在最适检测体系下,所构建的无酶电化学传感器对抗坏血酸检测具有较高的灵敏度,抗坏血酸浓度在1~100 mmol/L范围内,电流响应与其具有良好线性关系,工作曲线方程为y=867.81x+3.860 8(R~2=0.991 9),检出限为0.011 7 mg/L。此外,所构建的无酶电化学传感器已成功地应用于实际样品检测。鉴于此,所提出的新型无酶电化学分析方法在食品质量控制和安全检测等领域有着巨大的应用前景。     

Fe3O4@Au-Cu/金属有机框架纳米酶电化学传感器检测食品中亚硝酸盐

目的 基于类酶活性的自组装材料构建金属有机框架（Fe3O4@Au-Cu/MOF）实现食品中亚硝酸盐的检测。 方法 采用透射电子显微镜和傅里叶红外光谱对合成的Fe3O4@Au-Cu/MOF进行表征。利用循环伏安法,通过改变Fe3O4@Au-Cu/MOF添加量、温度、扫描速率以及pH值进行单因素和正交实验。根据最优体系对1~100 mmol/L的亚硝酸盐进行检测,绘制工作曲线,进行抗干扰实验和实际样品检测。 结果 合成的Fe3O4@Au-Cu/MOF具有催化活性高、暴露活性位点多和孔隙率高等优势。当Fe3O4@Au-Cu/MOF添加量为0.0075 g,温度为40°C,扫描速率为0.08 V/s,pH值为7时为最优检测体系。工作曲线为y=0.36118x+15.57962,R2=0.99603,检测限为1.6 μmol/L (S/N=3),具有较强的抗干扰性。在实际样品检测中,回收率为98.78%~102.58%,RSD小于4%。 结论 与现有方法相比,合成的Fe3O4@Au-Cu/MOF催化过H2O2产生氧化活性物质,促进亚硝酸盐氧化,增加体系中电荷移动的能力更强。该方法构建的电化学传感器具有可靠、方便、灵敏和成本低等特点,为食品中亚硝酸盐的检测提供了一种新的思路。     

Fe_3O_4@Au模拟酶快速检测亚硫酸盐的研究

以水热法合成磁性Fe_3O_4微粒,通过对其表面氨基化修饰与金纳米粒子自组装方法构建金磁微粒(Fe_3O_4@Au),并表征其性能。Fe_3O_4@Au纳米微粒能够有效地催化过氧化氢氧化底物2,2′-联氮-双-3-乙基苯并噻唑啉-6-磺酸(ABTS),产生颜色变化。利用亚硫酸根离子具有较强的还原性,可使氧化的显绿色的ABTS+褪色为ABTS的原理,建立一种亚硫酸根的快速比色检测方法,优化检测体系,分析其回收率和选择性。结果表明,氨基化的Fe_3O_4纳米粒子可以有效固载金纳米粒子,金磁微粒饱和磁化强度为43emu/g。检测体系最优条件为:H_2O_2浓度0.1mol/L,催化温度70℃,反应时间60s。在优化条件下,亚硫酸根浓度在0.0001～0.02mol/L范围内具有良好的线性关系,线性相关系数R~2值为0.9872,检测限为1.47μmol/L,样品回收率为95.26%～110%,选择性良好。该研究对食品中亚硫酸盐的检测具有潜在的应用价值。     

基于无花果蛋白酶快速检测维生素C含量的方法研究

无花果蛋白酶具有过氧化物模拟酶活性,能催化H2 O2产生·OH,从而氧化底物ABTS发生显色反应,而具有强抗氧化性的维生素C可清除自由基,从而诱导绿色ABTS+·还原为无色的ABTS,基于此建立高选择、高灵敏、快速检测食品中维生素C含量的比色检测方法,优化方法并对维生素C的检测性能进行评估.研究结果表明,检测方法较优方案组合为:H2 O2浓度0.5 mol/L,无花果蛋白酶质量浓度0.5μg/mL,温度50℃,孵育时间30 s.在优化条件下,维生素C浓度在0.001～0.080 mmol/L范围内呈良好的线性关系,线性回归方程为y=7.381 x+0.1091,相关系数R2值为0.9923,检出限为0.43μmol/L,说明该检测方法灵敏度高;同时此比色检测方法加标回收率在95％ ～105％,且其选择性高和稳定性好,在食品分析、生物化学和医药应用等方面具有很好的应用前景.     

基于Fe3O4/GCE磁性传感器检测水中苯酚

目的 利用Fe3O4/GCE磁性传感器对水中的苯酚进行定量分析。方法 合成了Fe3O4磁性纳米材料,以玻碳电极(Glassy carbon electrode,GCE)为工作电极,制备了Fe3O4/GCE传感器。结果 Fe3O4具有良好的导电性、吸附性以及电催化活性,能够显著提高传感器的灵敏度。Fe3O4/GCE检测苯酚的最佳条件为5 μL 1 mg/mL的Fe3O4制备Fe3O4/GCE,以1.0 mol/L的H2SO4为支持电解质溶液。在最佳检测条件下苯酚浓度与其氧化峰电流在2-270 μg/L呈线性关系,线性方程为Y=0.4544X-0.921,R2=0.9976,检出限为1.084 μg/L(S/N=3),检出限较低, 加标回收率在95.84-99.67%之间,回收效果较好,准确度较高且该传感器重复性和稳定性较好连续扫描8次的RSD为2.58%,保存35天后,其对50 μg/L的苯酚的测试效果仍可达到最初的91.21%。结论 制备的Fe3O4/GCE操作简单、快捷且成本较低可用于苯酚现场的快速检测分析。     

基于Nafion/Hb/Fe3O4@Cs/GCE传感器检测油炸食品中丙烯酰胺

目的 制备Nafion/Hb/Fe3O4@Cs/GCE传感器, 并应用于油炸食品中丙烯酰胺(acrylamide, AM)的检测分析。方法 制备Fe3O4@碳球纳米复合材料(Fe3O4 carbon sphere nanocomposites, Fe3O4@Cs), 并复合Nafion和血红蛋白(hemoglobin, Hb), 以玻碳电极(glassy carbon electrode, GCE)为工作电极制备Nafion/Hb/Fe3O4@Cs/GCE传感器, 通过对固载方式、Hb固载量、加成温度以及加成时间的优化确定Nafion/Hb/Fe3O4@Cs/GCE对丙烯酰胺进行定量检测的最佳检测条件。结果 Fe3O4@Cs导电性良好, 能显著提高Nafion/Hb/Fe3O4@Cs/GCE传感器的灵敏度。AM与Hb的加成率与其浓度负对数在1×10?5~1×10?9 mol/L范围内呈良好的线性关系, 线性方程为Y=?5.254X+60.01 (X为AM浓度的负对数), r2=0.9973, 检出限为2.134×10?10 mol/L, 加标回收率在95.6%~98.4%之间, 相对标准偏差小于1.45%。结论 该方法简单、方便快捷, 适用于油炸食品中AM的定量分析。     

基于新型金属有机框架模拟酶的电化学检测食品胆固醇体系的构建

基于金属有机框架具有模拟酶的特性,构建实时检测胆固醇电化学传感器。采用自组装的方法制备出新型的复合金属有机框架模拟酶(Fe₃O₄@Au/MOF)纳米粒子,其兼具了Fe₃O₄磁性粒子的可回收特点以及金纳米粒子的加速电子转移等优点。并利用红外光谱、透射电子显微镜以及X射线光电子能谱对制备成功的Fe₃O₄@Au/MOF的结构和形貌进行表征。借助Fe₃O₄@Au/MOF的类过氧化物酶双重催化性能使胆固醇氧化为胆甾烯三酮和H₂O₂,而H₂O₂在其进一步的催化下产生的具有氧化活性的羟基自由基可促进3,3′,5,5′-四甲基联苯胺发生氧化还原反应,进而增加了体系中电荷的移动。根据电信号的响应情况, 从而实现对胆固醇的快速定性和高效定量的检测。研究结果表明,采用循环伏安法测得优化检测体系为:反应温度为 50℃,Fe₃O₄@Au/MOF 添加量为0.0125g,扫描速率为0.10V/s,缓冲溶液pH=4；当胆固醇浓度处于0.001~1.500mmol/L时呈现良好的线性关系,线性回归方程为y=20.6401x+4.7722,R²=0.9956,最低检测限为2.7μmol/L；且检测体系具有良好的回收率和抗干扰性,在食品分析和生化分析等方面具有良好的应用前景。     

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.     

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     

INFOPRINT 2014 was Successfully Held in Dongguan

Sponsored by Printing and Printing Equipment Industries Association of China （PEIAC） and organized by Print China magazine, the Seventeenth Beijing International Printing Information Conference （INFOPRINT 2014） was successfully held on 11th Dec. 2014 at Dongguan Exhibition International Hotel.