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...     

基于Au@PtNPs-Cu-MOF/GCE传感器检测果蔬中葡萄糖

制备了新型的金@铂纳米复合材料-铜金属有机骨架/玻碳电极传感器(Gold platinum nanocomposites-Copper metal organic skeleton/Glassy carbon electrode, Au@PtNPs-Cu-MOF/GCE)对水果中的葡萄糖进行快速检测分析。制备了二维的Cu-MOF纳米材料,并在其表面负载核壳结构的Au@PtNPs,合成了一种新型的Au@PtNPs-Cu-MOF纳米复合材料。利用Au@PtNPs-Cu-MOF构建了一种新型的Au@PtNPs-Cu-MOF/GCE,通过对电解质pH、计时安培电位的优化,确定Au@PtNPs-Cu-MOF/GCE的最佳工作条件,对梨中的葡萄糖进行定量分析。研究发现,葡萄糖浓度与其峰电流分别在0.1-10和10-2600 μmol/L范围内呈良好的线性关系,检出限(S/N=3)为0.0872 μmol/L,线性范围宽,检出限低,明显优于其它的葡萄糖无酶传感器。且Au@PtNPs-Cu-MOF/GCE的重复性和抗干扰能力较好,8次扫描的相对标准偏差为1.32%。对梨汁中的检测结果为1.8457 mmol/L与高效液相色谱法一致且偏差仅为5.46%,符合检测要求。     

基于GOx/NiO@Au-Pt-PGA/GCE酶传感器检测葡萄糖的研究

目的 构建了GOx/NiO@Au-Pt-PGA/GCE传感器对果蔬中的葡萄糖进行快速定量分析。方法 在氧化镍纳米材料(Nickel oxide nanomaterials, NiO)的基础上复合金-铂纳米复合材料(Gold-platinum nanocomposites, Au-Pt)合成了新型的NiO@Au-Pt纳米复合材料,以玻碳电极(Glassy carbon electrode, GCE)为工作电极,聚谷氨酸(Poly-(γ-glutamic acid), PGA)为交联剂,交联葡糖糖氧化酶(Glucose oxidase, GOx)和NiO@Au-Pt制备了GOx/NiO@Au-Pt-PGA/GCE传感器。通过对交联剂浓度、静置时间等的优化确定检测体系最佳工作条件。结果 研究发现,NiO@Au-Pt具有良好的导电性和催化作用,PGA具有良好的生物相容性和协同作用,GOx/NiO@Au-Pt-PGA/GCE能有效提高传感器的灵敏度,增强电流响应。GOx/NiO@Au-Pt-PGA/GCE的最佳工作条件为1.0%的PGA作为制备传感器的交联剂,静置时间20 s。在最佳条件下,葡萄糖浓度与其峰电流在0.01~9.0 mmol/L内呈线性关系,Y=4.1858X+0.169,R2=0.9946,检出限(S/N=3)为2.43 μmol/L。GOx/NiO@Au-Pt-PGA/GCE对梨汁中葡萄糖检测结果与国标规定的高效液相色谱法一致,RSD为3.72%,且GOx/NiO@Au-Pt-PGA/GCE稳定性较好,4 ℃保存15 d后其峰电流仅降低了4.89%,对常见的共存干扰物有较好的抗干扰能力。结论 GOx/NiO@Au-Pt-PGA/GCE简单便捷、稳定性好,可用于果蔬中葡萄糖的快速分析。     

非共价作用石墨烯-金纳米复合材料修饰电极的制备及检测双酚A的方法研究

基于阳离子-π非共价作用力制备石墨烯-金纳米复合材料(graphene-AuNPs),研究基于该纳米复合材料修饰玻碳电极建立电化学传感定量检测水样中双酚A的方法。采用扫描电镜(SEM),EDS能谱和X-射线衍射(XRD)技术对该复合材料进行表征,同时制备基于纳米材料修饰的玻碳电极(graphene-AuNPs/GCE),研究双酚A在修饰电极表面的电化学行为,并将该传感器应用于实际样品中双酚A含量的检测。结果表明,所制备的复合材料结构稳定,分散无团聚现象,粒子尺寸大小均匀;所修饰的纳米材料电极对双酚A有明显的电催化性能,双酚A在修饰电极上的电流响应是裸玻电极的6.3倍。在优化条件下,双酚A在浓度为5.7~570 ng/m L和570~2280 ng/m L范围内与氧化峰电流呈线性,检测限为1.9 ng/m L(S/N=3)。将该修饰电极应用于水体样品中双酚A的检测,回收率在78.91~115.54%。     

基于镍/铜双金属有机骨架@纳米金纳米复合材料/离子液体制备新型酶传感器检测敌敌畏

构建镍/铜双金属有机骨架@纳米金新型纳米复合材料(Nickel/copper bimetallic organic skeleton@nano gold,Ni/Cu-MOF@Au)/离子液体/玻碳电极(Glassy carbon electrode,GCE)酶传感器检测敌敌畏。制备Ni/Cu-MOF@Au，并复合离子液体1-丁基-3-甲基咪唑六氟磷酸盐(1-Butyl-3-methylimidazole hexafluorophosphate,[MBIM][PF₆])构建Ni/Cu-MOF@Au/[MBIM][PF₆]/GCE传感器，并对传感器的修饰材料比例、抑制时间等工作条件进行优化，确定传感器的最佳工作条件为[MBIM][PF₆]与Ni/Cu-MOF@Au的比1.5:1000、修饰量5.0μL、抑制时间5 min。在最优试验条件下，敌敌畏浓度与其对传感器抑制率的负对数在2.0×10^-11～1.0×10^-5 g/L范围内呈线性关系，检出限为(按抑制率10%计算)1.6452×...     

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ZIF-8/Au@f-CNF增敏型双酚A电化学传感器的构建及性能研究

摘 要：目的 设计制备了金属有机框架ZIF-8掺杂、负载金纳米粒子的碳纳米纤维复合材料（ZIF-8-doped gold nanoparticles-loaded carbon nanofibers, ZIF-8/Au@f-CNF），用于玻碳电极（glassy carbon electrode, GCE)表面功能化修饰，以构建食品中双酚A污染物的增敏型电化学传感，并探索对双酚A的增敏检测机制。方法 将利用室温溶剂法制备的ZIF-8与原位还原法制备的负载金纳米粒子的碳纳米纤维（gold nanoparticles-loaded carbon nanofibers, Au@f-CNF）超声混合，滴注在GCE电极表面，构建ZIF-8/Au@f-CNF电化学传感器。运用X-射线光电子能谱仪（X-ray Photoelectron Spectroscopy, XPS）和透射电子显微镜（transmission electron microscopy, TEM）、循环伏安法（cyclic voltammetry, CV）和电化学阻抗法（electrochemical impedance spectroscopy, EIS）对材料表面形貌和电化学性能进行表征，考察了扫速和pH值等参数对双酚A电化学传感行为的影响。结果 ZIF-8/Au@f-CNF复合材料显示较为均匀的掺杂状态，经ZIF-8/Au@f-CN修饰后的GCE电极（ZIF-8/Au@f-CNF/GCE）电活性面积明显提升，是未经修饰裸GCE面积的1.62倍，对双酚A的氧化峰电流峰值显著提升至原来的2.84倍。结论 将ZIF-8的多孔特性和Au@f-CNF的电催化性能相结合，赋予ZIF-8/Au@f-CNF/GCE对目标物良好的吸附性能和电化学反应活性，基于纳米材料的协同效应可实现对双酚A的增敏传感检测，该研究为新型复合材料的开发及增敏传感器构建提供了研究思路和方法借鉴。     

基于铁/碳纳米复合材料@1-氨丙基-3-甲基咪唑盐离子液体/玻碳电极检测肉制品中氨基脲

目的 制备铁/碳纳米复合材料(iron/carbon nanocomposites,Fe/Cs)@1-氨丙基-3-甲基咪唑盐离子液体(1-aminopropyl-3-methylimidazole salt ionic liquid,IL-NH2)/玻碳电极(glassy carbon electrode,GCE)传感...     

基于Pd/MWCNTs/玻碳电极的电化学传感器检测水样中的羟胺

目的 采用Pd/MWCNTs纳米复合材料修饰玻碳电极构建电化学传感器,检测养殖水样及水产饲料中羟胺（NH2OH）的含量。方法 采用乙二醇还原法制备Pd纳米颗粒负载于碳纳米管上制备Pd/MWCNTs纳米材料,运用XRD(X-ray diffraction)和TEM (transmission electron microscopy) 手段对材料进行表征,构建基于Pd/MWCNTs/GCE的电化学传感器检测羟胺。 结果 在优化的工作条件下,Pd/MWCNTs纳米复合材料修饰电极检测羟胺线性检测范围2.0 μmol/L-1.4 mmol/L,检测下限达0.60 μmmol/L (S/N = 3),灵敏度为61.48 μA/mmol/L,是MWCNTs修饰电极检测灵敏度的10倍左右。结论 复合材料制备的传感器检测羟胺具有灵敏度高、线性范围宽、检测下限低的特点,可用于抗氧化剂羟胺的检测。     

基于二氧化钛@金/羧甲基壳聚糖/玻碳电极传感器同时检测饮用水中重金属铅和镉的研究

目的 制备二氧化钛@金/羧甲基壳聚糖/玻碳电极(titanium dioxide@gold nanoparticles/carboxymethyl chitosan/glassy carbon electrode,TiO2@Au/CMCS/GCE)传感器对饮用水中的铅和镉同时进行检测分析.方法 制备了二氧化钛纳米材料(...     

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.