高效液相色谱-串联质谱法测定牛奶中3种磺胺类药物残留不确定度的评定

目的采用高效液相色谱-串联质谱法对牛奶中磺胺吡啶、磺胺噻唑和磺胺甲基异恶唑残留的不确定度进行评估。方法建立测定牛奶中磺胺吡啶、磺胺噻唑和磺胺甲基异恶唑含量不确定度的数学模型,确定不确定度来源并对其评定。结果当牛奶中磺胺吡啶含量为5.09μg/kg时,其扩展不确定度为0.62μg/kg(k=2);当牛奶中磺胺噻唑含量为8.62μg/kg时,其扩展不确定度为0.71μg/kg(k=2);当牛奶中磺胺甲基异恶唑含量为10.15μg/kg时,其扩展不确定度为0.81μg/kg(k=2)。其中,测量重复性和标准曲线对不确定度的影响最大。结论影响检测结果不确定度的主要因素为样品测量的重复性、标准曲线拟合和样品的前处理过程。     

动物源性食品中痕量磺胺兽药残留的分析

以多壁碳纳米管作为固相吸附材料，与高效液相色谱联用建立食品中痕量磺胺兽药残留的分析方法，对富集条件和分离条件进行了详细优化。以1μg/L的10种磺胺混合标准溶液富集100mL，9次平行测定的峰面积相对标准偏差（RSD）在2．56％～7．62％，10种磺胺的最低检测限（S／N=3）在2．1ng／L～9．3ng／L，线性范围均在0．2μg／L-15μg/L之间。实际样品加标回收率范围为70.18％～85．68％，相对标准偏差范围为1．02％～14．56％。     

液相色谱-荧光检测法同时测定肠衣中八种磺胺类兽药残留

建立了一种专属性强的高效液相色谱-同时测定肠衣中八种磺胺类药物残留(磺胺嘧啶、磺胺间甲氧嘧啶、磺胺甲基嘧啶、磺胺对甲氧嘧啶、磺胺喹恶啉、磺胺甲基异恶唑、磺胺甲氧嗪和磺胺二甲嘧啶)的检测方法。采用1%乙酸/乙腈对肠衣中的磺胺类药物残留进行提取,用正己烷净化,净化后的样品,经荧光胺衍生,供液相色谱仪测定。实验结果表明,八种磺胺药物在2.00～5.00×102ng/ml浓度范围内,具有良好的线性关系,线性相关系数在0.9982～0.9997,添加浓度为5～50ng/ml时,回收率在63.7%～87.8%之间,该方法的最低检测限为5ng/ml,完全可以达到日常检测要求。     

建立同时快速测定动物源性食品中17种农药的在线凝胶渗透色谱-气相色谱-质谱联用法

目的建立猪肉、鸡蛋、牛奶、猪脂肪等动物源性食品中同时检测17种农药残留的在线凝胶渗透色谱-气相色谱-质谱联用法(GPC-GC-MS)。方法样品用正己烷饱和乙腈溶液均质提取,加入氯化钠盐析,离心分层,取部分乙腈层经固相萃取(NH2)柱净化,利用在线GPC-GC-MS测定。结果在0.85~30μg/L范围内相关系数均在0.95以上,回收率在61.2%~126%之间。17种农药残留最低检出限范围(以信噪比S/N≥3计)为0.25~3.00μg/L,定量限范围(以信噪比S/N≥10计)为0.85~10.0μg/L。结论该法有效、耐用、快速、灵敏,符合法规残留限量检测要求。     

虾中硫丹残留的酶联免疫吸附检测方法的研究

目的:建立一种虾中农药硫丹残留的快速检测方法.方法:采用酶联免疫吸附试验(ELISA)测定农药硫丹残留.提取溶剂为丙酮.该检测方法中用阴性样品作标准曲线.结果:该方法的检出限(IC15)约为1.6 μg/L,灵敏度(IC50)约为17μg/L.线性范围1.8～60μg/L.平均回收率67.56%～99.81%.结论:该检测方法符合<日本肯定列表>中规定的水产品中硫丹的检测要求,且样品的处理过程较为简单,适用于大量样品的快速检测.     

荧光定量技术快速检测生乳中磺胺类药物残留

目的 利用荧光定量技术分析检测生乳中磺胺类药物残留。方法 取生乳空白样品进行加标回收试验(磺胺噁唑13.5 μg/L、27 μg/L;磺胺喹噁啉5 μg/L、10 μg/L;磺胺嘧啶0.82 μg/L、1.64 μg/L),样品经过简单的处理后15 min就可以得到实时分析结果。结果 分析结果显示回收率均在82.18%～118.40%;批内、批间变异系数均低于15%,最低检测限为5 μg/L,与国标方法(GB/T 22966-2008)相对比,结果完全符合。结论 该方法具有操作简单、价格低廉、检测时间短、良好的检测效果和结果准确的优点,具有对大批量乳制品的快速检验和质量验收的推广潜力, 能为生乳的检测工作和品质评价提供科学参考。     

基于荧光法的牛奶中单诺沙星的快速检测

采用荧光法结合化学计量学来建立牛奶中单诺沙星(DANO)残留的快速检测方法 先利用加标法制备含有不同浓度的DANO(0～56μg/L)的全脂奶作为校正集,除蛋白后经扫描得到荧光光谱,利用化学计量学技术对其进行主成分分析(PCA)并建立偏最小二乘法(PLS)和判别分析(PLSDA)模型.采用加入不同浓度DANO的4种品牌的超高温杀菌和巴氏杀菌牛奶作为预测集,验证了两种模型的准确性.实验结果表明,定性模型可以准确地将阴性与阳性样品区分,定量模型预测出的样品回收率在88％ ～ 114.4％,预测误差在可接受范围内.     

高通量微生物显色法快速检测动物源性食品中抗生素残留

建立一种采用高通量微生物显色法对动物源性食品中抗生素残留进行筛检,再结合高效液相色谱-串联质谱(high performance liquid chromatography-tandem mass spectrometry,HPLC-MS/MS)法对阳性样品进行复测的分析检验方法。本方法利用嗜热脂肪芽孢杆菌(Bacillus sterothermophilus)作为指示菌,制备96微孔板,可同时对不同类别多种抗生素进行联合检测。结果表明:该微生物显色法操作简便、快捷,成本低,结果准确且易判断,选取pH 7.4磷酸盐缓冲液进行提取,以反应液150μL、菌液50μL(初始OD_(600 nm)为0.4左右)、样品提取液100μL作为检测体系,检测效果最佳,对动物源性食品中氨基糖苷类检出限为60μg/kg,β-内酰胺类检出限为20~40μg/kg,大环内酯类检出限为60~80μg/kg,四环素类检出限为40~60μg/kg,符合国内外对抗生素残留限量的要求。对60份动物源性样品进行检测,其结果与HPLC-MS/MS复测结果一致,说明该微生物法稳定性良好,可用于动物源性食品中抗生素残留的初筛检测。     

表面增强拉曼光谱快速检测西瓜中甲基异柳磷农药残留

为实现西瓜中甲基异柳磷农药残留的快速检测,本文利用表面增强拉曼光谱技术结合化学计量学方法建立了西瓜中甲基异柳磷农药残留的快速检测模型。结果表明,甲基异柳磷在1043 cm~(-1)处有最强的拉曼峰,在0~5μg/g的浓度范围内其强度随甲基异柳磷浓度增强而增强。对西瓜中甲基异柳磷农药的原始表面增强拉曼光谱进行预处理后建立主成分分析模型,得到最低检测限为0.01μg/g,再建立偏最小二乘模型,对模型进行验证,分析得出农药浓度在0~5μg/g时模型的校正集相关系数与验证集相关系数分别为0.9960和0.9952,模型的校正均方根误差(RMSEC)和验证均方根误差(RMSECV)分别为0.163和0.183。结果表明,利用表面增强拉曼光谱技术可以实现西瓜中甲基异柳磷农药残留的快速检测。     

动物源性食品中抗生素残留、耐药细菌的分布及耐药基因的水平传播

目的：调查动物源性食品中抗生素的残留、耐药细菌的分布及抗生素对耐药基因水平转移的影响。方法：利用盐析辅助液液萃取/高效液相色谱/串联质谱法对市售动物源性食品中18种抗生素的含量进行检测;对样品中的需氧菌进行分离鉴定,利用PCR技术调查耐药基因的分布,通过接合转移试验调查抗生素胁迫对耐药基因水平传播的影响。结果：50份动物源性食品中检出环丙沙星、恩诺沙星、土霉素、金霉素、磺胺嘧啶和磺胺二甲嘧啶。162株分离株中磺胺甲基异恶唑耐药基因sul1的检出率最高。在环丙沙星胁迫下,三株供体菌中耐药基因qnrS的接合转移率均高于对照组。结论：动物源性食品中喹诺酮类、磺胺类和四环素类抗生素均有不同程度的残留。亚抑菌浓度抗生素促进耐药基因的接合转移。     

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.     

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.     

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.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.     

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.