纳米金掺杂石墨烯修饰玻碳电极选择性测定多巴胺

构建纳米金(Au)掺杂石墨烯(GS-Nafion)修饰玻碳电极(GCE)的电化学传感器(GCE/GS/Nafion/Au),研究多巴胺(DA)和抗坏血酸(AA)在上述电极的电化学行为,并用于DA的选择性测定。将GS-Nafion溶液涂覆于GCE表面制得GCE/GS/Nafion电极,采用化学镀方法于GCE/GS/Nafion电极表面生成Au制得GCE/GS/Nafion/Au电极,采用扫描电镜(SEM)表征GS、化学镀Au和电极的制备过程,循环伏安(CV)法和示差脉冲伏安(DPV)法研究DA的电化学性质。在优化的实验条件下,DA浓度与DPV法氧化峰电流大小在1.0×10-7～1.0×10-4mol/L之间呈线性关系,线性相关系数为0.9988,检出限为4.2×10-8mol/L。该电极制备过程简单、灵敏度高、抗干扰性强,可以用于DA的测定,结果令人满意。     

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。     

原位合成铜基金属有机框架差分脉冲伏安法快速检测肉制品中亚硝酸盐

为构建肉制品中亚硝酸盐的快速检测方法,本实验采用电化学法在玻碳电极（glassy carbon electrode,GCE）表面原位合成铜基金属有机框架（Cu-based metal organic frameworks,Cu-MOFs）,制备亚硝酸盐电化学传感器。合成的Cu-MOFs在电极表面均匀分布,利用扫描电镜可以看到单个Cu-MOFs颗粒呈八面体形状。NO2－在电位作用时失去电子以发生氧化反应,依据电子转移产生的电流信号,可实现NO2－的定量检测。电极表面修饰的Cu-MOFs能够催化NO2－的氧化反应,可有效增强电极的响应信号,有利于提高NO2－检测的灵敏度。使用Cu-MOFs/GCE结合差分脉冲伏安法对NO2－进行测定,NO2－的氧化峰电流与其浓度在10～1?200?μmol/L范围具有良好的线性关系,检测限为1.57?μmol/L,并且该传感器具有良好的选择性和稳定性。利用Cu-MOFs/GCE测定市售肉制品中亚硝酸盐含量,结果显示该传感器获得的检测结果与盐酸萘乙二胺法的结果基本一致,证明该电极可以用于食品亚硝酸盐的检测。     

基于Au@ZIF-67/rGO纳米复合材料构建的电化学传感器在抗坏血酸检测中的应用

先以氧化石墨烯(GO)、六水氯化钴(Ⅱ)、2-甲基咪唑为原料,在室温磁力搅拌条件下合成ZIF-67/GO纳米复合材料。再以氯金酸(HAuCl4)为原料,L-抗坏血酸(AA)为还原剂,在常温磁力搅拌条件下将Au还原到ZIF-67/GO表面,GO同时被还原为还原氧化石墨烯(rGO),从而制备Au@ZIF-67/rGO纳米复合材料。采用傅里叶变换红外光谱法(FT-IR)、场发射扫描电镜(FESEM)和X射线能谱仪(EDS)等技术对合成的材料进行表征。利用Au@ZIF-67/rGO纳米复合材料修饰玻碳电极(GCE)构建AA电化学传感器。采用循环伏安(CV)法研究了AA在Au@ZIF-67/rGO纳米复合材料修饰玻碳电极上的电化学行为。采用电流-时间(i-t)曲线法研究了检测电位、催化剂用量、pH对催化电流的影响,并确定检测AA的优化实验条件。在优化实验条件下,确定检测AA的线性范围为0.07634~7.14300 mmol/L,检测限(S/N=3)为0.03021 mmol/L。实验结果表明:Au@ZIF-67/rGO纳米复合材料对AA的氧化具有较高的电催化活性。该传感器为医学、食品、电镀、印染等领域AA的检测方法提供依据。     

碳量子点/聚吡咯修饰电极对违禁食品添加剂罗丹明B的检测

通过循环伏安法在玻碳电极(GCE)表面制备得到了掺杂十二烷基苯磺酸钠(SDBS)的聚吡咯(PPy)薄膜,并在0.1 mol/L Na OH溶液中进行过氧化处理,得到SDBS-OPPy/GCE。采用电解法制备得到碳量子点(CQDs),并将其修饰于SDBS-OPPy/GCE电极表面,成功构建了CQDs/SDBS-OPPy/GCE电化学传感器,对罗丹明B进行定量检测。在最佳条件下,该传感器展示了一个较宽的线性范围为:(0.05~10.0)μmol/L,较低的检测限:0.013μmol/L。同时,该传感器具有较好的重现性和稳定性。     

色氨酸在Nafion-聚半胱氨酸修饰电极上的电化学行为及分析测定

采用滴涂和电聚合的方法构筑Nafion-聚半胱氨酸修饰的玻碳电极(Nafion/L-cys/GCE),采用循环伏安法(CV)研究色氨酸在此修饰电极上的电化学行为,利用线性扫描伏安法(LSV)对色氨酸进行定量分析。结果表明,该修饰电极对色氨酸电化学氧化具有明显催化作用。色氨酸浓度在0.4×10-6~40.0×10-6mol/L范围内与氧化峰电流有良好线性关系,回归方程为I_pa(μA)=0.6997c(10-6mol/L)+5.3(R2=0.9844),检测限为1.0×10-7 mol/L。该方法用于香蕉中色氨酸的检测,回收率为95%~98%。     

腌菜中亚硝酸盐的电化学检测

采用电沉积的方法将磷钨酸(H3PW12O40)沉积到预先用PDDA处理的玻碳电极上制得磷钨酸(H_3PW_(12)O_(40))修饰玻碳电极,通过循环伏安法分析该电极的电化学性质,研究其对亚硝酸盐的电化学作用,并测定腌菜中亚硝酸盐的含量。亚硝酸盐在6.67×10~(-6)~8.01×10~(-5) mol/L浓度范围内与电极还原电流呈线性关系,I(μA)=1.4508+0.0581c(μmol/L),R~2=0.9985(n=12)。最低检出限:1.41×10-6 mol/L。响应电流达到95%时所需时间小于4s。该电极具有制备简单、响应快、灵敏度高、检测限低等特点,用于检测亚硝酸盐,效果良好。     

基于氧化锌@金纳米复合材料/玻碳电极电化学传感器检测双酚A

目的 制备了氧化锌@金纳米复合材料/玻碳电极(Zinc oxide@Gold nanocomposites/Glassy carbon electrode,ZnO@Au/GCE)传感器,对双酚A进行检测分析。方法 合成了氧化锌纳米花(Zinc oxide nano flower,ZnO)并在ZnO上面生长纳米金(Gold Nanocomposites,Au)制备了新型的ZnO@Au纳米复合材料。以ZnO@Au为修饰材料,采用玻碳电极(Glassy carbon electrode,GCE)构建了ZnO@Au/GCE)传感器。通过对缓冲液、ZnO@Au的优化,确定ZnO@Au/GCE的最佳工作条件,对双酚A进行检测分析。结果 ZnO@Au不仅导电性、稳定性好而且具有良好的催化性,可有效提高ZnO@Au/GCE的灵敏度。双酚A浓度与氧化峰电流分别在0.05~1.0 μmol/L和1.0~240 μmol/L范围内呈线性关系,检出限(S/N=3)为0.021 μmol/L,加标检测结果与高效液相色谱法一致,且该传感器重复性、稳定性和选择性较好对常见干扰物有良好的抗干扰能力。结论 ZnO@Au/GCE操作简便、快捷且准确度高可用于双酚A的快速定量分析。     

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(titanium dioxide nanomaterials,TiO₂)并在此基础上负载纳米金(gold nanoparticles,Au),制备了新型的二氧化钛@纳米金纳米复合材料(titanium dioxide@gold nanoparticles,TiO₂@Au)。以玻碳电极(glassy carbon electrode,GCE)为工作电极,羧甲基壳聚糖(carboxymethyl chitosan,CMCS)为交联剂,制备了TiO₂@Au/CMCS/GCE传感器。结果 TiO₂@Au具有良好的导电性,对Cd²⁺和Pb^2+...     

原位生长α-Co (OH)2纳米片修饰电极快速检测亚硝酸盐

本工作以硝酸钴为前驱体,通过一步电沉积法在玻碳电极表面原位生长氢氧化钴纳米片,构建了电化学传感器,研究了其对NO2-离子的电催化行为,建立了快速测定NO2-离子的电化学方法。通过扫描电子显微镜（Scanning electron microscope,SEM）、能量散射光谱（Elemental energy spectrum analysis,EDX）和电化学技术对所获得的纳米材料的形貌和性能进行表征,进一步研究该修饰电极快速检测NO2-离子的电化学行为和电催化机理。结果表明,同一浓度NO2-离子在不同扫描速度与电流响应间成正比关系,得到Co(OH)2/GCE界面的电化学过程受吸附控制。Co(OH)2/GCE对NO2-离子展现了良好的电催化性能,检测线性范围为1~15 mmol/L,检测限为0.29 mmol/L（S/N=3）。该传感器具有快速制备、催化活性好、易操作以及检测耗时短等特点,适用于亚硝酸盐的现场快速筛查。     

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.     

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.     

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