沙丁胺醇分子印迹电化学传感器的制备及应用

分子印迹膜作为一种人工抗体可以特异性的识别目标物从而提高传感器的选择性。在本文中,选用简便的电化学聚合法制备沙丁胺醇（sal）的分子印迹膜,构建一种灵敏度高、选择性好的电化学传感器。该实验首先通过恒电位沉积法（﹣0.2V）将纳米金粒子原位沉积到玻碳电极表面（制得AuNPs/GCE）,接下来,利用循环伏安法（CV）将功能单体邻苯二胺与sal电聚合在AuNPs/GCE表面,制备分子印迹聚合物膜。随后,使用0.5 M H2SO4洗脱分析印迹膜10 min后,得到沙丁胺醇分子印迹电化学传感器（Sal-MIP/AuNPs/GCE）。结果表明,该传感器对sal的响应范围为1×10-11~1×10-6mol/L,检出限为1×10-11 mol/L。其线性方程为△IP(μA)=34.079+2.9048lgc(mol/L),相关系数（R2）为0.9911,且具有较好的选择性。将此传感器应用于新鲜猪肉中sal的快速检测,采用加标回收法验证传感器的性能,发现该方法的回收率为94.41%~107.03%,相对标准偏差（RSD）为2.1~3.5%,有较好的应用价值。     

用于快速检测沙丁胺醇的分子印迹传感器的制备及其在食品检测中的应用

首先通过电沉积纳米金,电聚合聚硫堇对玻碳电极表面进行了修饰,之后利用沙丁胺醇为模板分子,通过电聚合α-甲基丙烯酸,制备了一种选择性具有特异识别功能的纳米金/聚硫堇/沙丁胺醇分子印迹电化学传感器。实验采用循环伏安法和差分脉冲法,对不同的修饰电极进行了表征,优化电极的制备和测定条件,研究了印迹传感器对模板分子的选择性响应。结果表明:最佳制备条件下,模板分子:功能单体=1:4,聚合15圈,以0.5 mmol/L硫酸:乙腈(1:9,V/V)洗脱10 min,在pH=7.0的PBS溶液中进行DPV检测,线性范围为2.0×10~(-7)~1.0×10~(-4) mol/L,检测限为6.0×10~(-8) mol/L,S/N=3。该传感器灵敏度高,抗干扰能力强,重现和稳定性好。利用制备的分子印迹电化学传感器对食品中的沙丁胺醇进行了测定,回收率在86.5%~111.9%(n=3),结果令人满意。     

联苯三唑醇分子印迹电化学传感器的制备及识别性能研究

以联苯三唑醇为模板分子,通过电聚合邻苯二胺,在玻碳电极表面制备了对模板分子具有特异识别的分子印迹电化学传感器。实验选用铁氰化钾(K3[Fe(CN)6])作为电活性探针,采用循环伏安法(CV)和差分脉冲伏安法(DPV)研究了该传感器的电化学特性,并且优化了制备条件,研究了印迹传感器对模板分子及其结构类似物的选择性响应。结果表明:在最佳聚合条件下,p H=7.2,模板分子:功能单体=1:4(c/c),聚合圈数15圈,洗脱时间为13 min,洗脱剂:0.5 mol/L硫酸:乙腈=1:9(V/V),连续洗脱10次之后,相对标准偏差为5.2%,且传感器性能无衰减现象。该分子印迹电化学传感器灵敏度高,抗干扰能力强,对联苯三唑醇及其结构类似物具有良好的选择性响应,可以对结构类似物分别进行测定,为快速检测食品中联苯三唑醇奠定了基础。     

基于还原氧化石墨烯的电化学适配体传感器对黄曲霉毒素M1的检测

本实验基于还原氧化石墨烯（RGO）构建了一种用于黄曲霉毒素M₁（AFM₁）检测的电化学适配体传感器。采用红枣汁还原氧化石墨烯（GO）制备RGO,RGO通过滴涂法修饰在玻碳电极（GCE）表面,利用电沉积法将纳米金修饰在RGO/GCE上,AFM₁的适配体（Apt）通过Au-S键固定在AuNPs/RGO/GCE电极表面用于靶标AFM₁的捕获。当AFM₁存在时,AFM₁与适配体特异性结合形成AFM₁-Apt复合物,该复合物阻碍了电子的传递,导致电化学信号减弱。对RGO的制备条件进行优化,利用差示脉冲伏安法（DPV）监测电极表面的电化学信号,并对不同类型的毒素（黄曲霉毒素B₁、黄曲霉毒素B₂、赭曲霉毒素A和伏马毒素B₁）、不同浓度的AFM₁（1×10?7~5×10?4 ng/mL）以及羊乳样品进行检测以确定电化学适配体传感器的特异性、灵敏性和实用性。结果表明,GO:红枣汁=2:1（V:V）,pH=11时所制备的RGO的导电能力最强。传感器的电信号与AFM₁浓度的对数呈线性关系,检测范围为1×10?7~5×10?4 ng/mL,检测限为3.3×10?5 pg/mL,同时所建立的方法仅对AFM₁的检测有响应,而对干扰毒素无响应,说明电化学适配体传感器的特异性良好。使用建立的AFM₁电化学适配体传感器对羊奶中的AFM₁含量进行测定,发现所构建的传感器具有很高的灵敏性和良好的选择性,有望应用于食品工业中真菌毒素的快速、准确检测当中。     

胺菊酯分子印迹电化学传感器的制备及性能

以胺菊酯为模板分子,邻氨基苯酚为功能单体,通过循环伏安法在玻碳电极表面电聚合一层带有特异选择性能的胺菊酯分子印迹膜,构建一种能够快速检测样品中胺菊酯的分子印迹电化学传感器。实验应用非常规去除模板分子的方法即电位诱导法,选择铁氰化钾为电活性探针,采用循环伏安法和差分脉冲伏安法优化传感器的制备方法与检测条件,研究传感器的印迹效应和分析性能,并将该传感器用于食品中胺菊酯残留的快速检测。结果表明,电位诱导法较传统的浸泡洗脱法去除模板分子的效果好,胺菊酯浓度与其差分脉冲伏安电流差在0.2~10μmol/L范围内线性关系良好,检出限为0.07μmol/L,样品加标平均回收率在82.9%~98.2%之间。该传感器检测胺菊酯操作简单、响应迅速、灵敏度高、稳定性和选择性好、抗干扰能力强、检测成本低,具有良好的应用前景。     

喹乙醇印迹传感器的制备及其在喹噁啉类药物残留快检中的应用

以纳米银溶胶和纳米石墨烯为电极修饰材料,制备以喹乙醇为模板分子,邻氨基苯酚和间苯二酚为复合功能单体的一种新型快速检测喹噁啉类药物的印迹传感器。运用紫外光谱法选择最优功能单体,并研究模板分子与功能单体之间的作用形式和作用强度,结合电化学分析法优化制备条件并测定该印迹传感器的分析性能。在乙醇-0.4 mol/L NaOH溶液（3∶1,V/V）中洗脱20 min,实现模板分子的高效洗脱。以K3[Fe(CN)6]作为电活性探针,通过响应电流变化对4 种喹噁啉类兽药含量进行间接测定。结果表明,该印迹传感器对喹乙醇具有较高的选择性和灵敏度,对其结构类似物也有特异吸附作用,样品加标平均回收率为89.05%～100.86%,相对标准偏差在1.03%～3.11%之间（n=5）。该传感器成功应用于动物源性食品中喹噁啉类促生长剂药物残留的灵敏快速检测。     

基于纳米金信号放大的分子印迹膜-SPR传感器检测奶制品中的三聚氰胺

采用分子印迹和SPR信号放大技术,构建一种以嵌有纳米金的分子印迹膜为识别元件,用于检测奶制品三聚氰胺的分子印迹膜-表面等离子体共振传感器(MIM-SPR)。首先利用表面热引发聚合的方法在SPR金片表面合成嵌有纳米金的分子印迹膜,再对MIM-SPR传感器的吸附响应性、选择性、再生性及精准度进行评价。该传感器的响应值与三聚氰胺在1×10-2~2μg/m L浓度范围内线性关系良好,R2=0.998。加标浓度在0.5~1.5μg/m L范围内的回收率为86.43%~107.11%,RSD小于6.0%(n=5)。结果表明该方法操作简单、选择性和再生性好、精准度高,可用于奶制品三聚氰胺残留量的测定。     

分子印迹光子晶体传感器的制备及其对酒类食品中邻苯二甲酸二丁酯的快速检测

以邻苯二甲酸二丁酯（dibutyl phthalate,DBP）为目标分析物,结合分子印迹技术与光子晶体,构建基于分子印迹光子晶体凝胶膜（molecularly imprinted photonic hydrogels,MIPHs）的传感器用于酒类中的DBP快速检测。最佳条件下,构建的传感器对DBP的响应时间为3 min,当DBP质量浓度为0.01～0.1 mg/L时,MIPHs的衍射峰位移与DBP质量浓度呈良好的线性关系（R2＝0.992 0）,检出限为0.01 mg/L（RSN＝3）。采用制备的MIPHs对白酒中DBP分子进行检测,对DBP的加标回收率在95.60%～103.20%之间。研究表明,制备的DBP分子印迹光子晶体传感器具有操作简便、响应快速、选择性高和成本低的优点,在酒类中有害物的安全快速筛查检测具有广阔的应用前景。     

基于石石墨烯的丁酰胆碱酯酶传感器法快速测定水产品中的孔雀石绿

本文以壳聚糖（Chitosan）和石墨烯GS为复合修饰材料,通过交联技术固定化丁酰胆碱酯酶（BuChE）制备了BuChE/CS/GS/GCE纳米酶传感器,建立了一种快速而灵敏测定水产品中孔雀石绿（Malachite Green,MG）的方法。研究了BuChE/CS/GS/GCE纳米酶传感器修饰材料、电解质、固定酶量、抑制时间等对酶传感器响应电流的影响,优化了酶传感器法测定MG的试验条件,结果如下：修饰材料CS与GS之比为1:2、0.10 mol/L的PBS为电解质、pH 7、抑制时间为11 min、酶活是4.0 U/mL。在此条件下,该酶传感器的响应电流与电解质溶液中MG的浓度在1.0×10-7~1.1×10-6 mol/L范围内成线性关系（Ip=-6.97 C MG+22.81,R2=0.9885）,最低检测限为2.80×10-8 mol/L（S/N=3）,加标回收率在96.36%~99.78%。该方法用于水产品中MG的测定具有简捷、灵敏度高、选择性好、稳定性好、重复性好等优点,用于水产品中孔雀石绿的快速检测是可行的。     

双通道尼泊金乙酯分子印迹传感器的研制与应用

以尼泊金乙酯(EP)为模板分子,邻苯二胺(o-PD)为功能单体,利用循环伏安法在玻碳电极(GCE)表面制备分子印迹膜,对分子印迹聚合条件进行了优化,并进一步在双通道丝网印刷碳电极(SPCE)表面进行电聚合,制得双通道尼泊金乙酯分子印迹膜电极(EP-MIP/SPCE)。利用循环伏安法、方波伏安法和电流-时间曲线法对分子印迹传感器的电化学性能进行评价。EP在双通道EP-MIP/SPCE上的氧化电流与EP在低浓度区(3.2×10~(-7) mol/L~3.2×10~(-6) mol/L)和高浓度区(2.7×10~(-5) mol/L~5.6×10~(-4) mol/L)分别呈良好的线性关系,检出限为9.7×10~(-8) mol/L。运用建立的方法对市售酱油中的EP进行了测定,加标回收率为97.2%~106.6%,实验结果表明,该双通道分子印迹传感器可对酱油等食品样品中的尼泊金酯类进行快速测定。     

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.     

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.     

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.     

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.     

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.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.