ICP-MS法快速测定餐用纸中金属污染物

建立等离子电感耦合质谱(ICP-MS)配合微波消解法检测餐用纸中铅、镉、砷、铬、镍、钡和锑的含量。样品经硝酸消解,微波程序升温法进行处理,ICP-MS同时测定其中7种金属污染物。结果表明:各元素的线性范围为0~100.0μg/L,标准曲线线性相关性良好,r≥0.999,7种元素方法检出限为0.003~0.243 mg/kg,加标回收率在90%~115%之间。样品前处理安全性高,消化过程方便易于控制,检测方法精密度高(RSD5%),实现了多元素同时快速测定,可用于食品接触用纸金属元素监测。     

ICP-OES法测定面制食品中铝含量

本文采用电感耦合等离子体发射光谱法进行测定,通过微波消解法对面制食品进行消解,该方法最低检出限0.027μg/m L,加标回收率为98.8%~102.1%,测定结果与国标方法 ICP-MS法比较检测数据不存在显著性差异。该方法具有灵敏度高、检测限低、线性范围宽、结果准确等特点,可以用于面制食品中铝的检测。     

ICP-MS法测定刺梨和无籽刺梨果实中有害重金属元素

建立了刺梨和无籽刺梨中痕量重金属元素的分析方法。采用微波消解-电感耦合等离子体质谱法(ICPMS)测定了As、Bi、Cd、Co、Cr、Ni、Pb、Sb和Sn共9种元素。结果显示,各元素在质量浓度范围0~100μg/L内线性良好,相关系数R≥0.999 8,ICP-MS对所测定重金属元素的方法检出限为0.150~9.495μg/kg,定量限为1.50~94.95μg/kg,精密度试验相对标准偏差为1.03%~4.71%,加标回收率在93.3%~102.4%之间。利用该方法分析了国家标准物质黄芪(GBW 10028),结果与证书值相符。该方法可快速、准确地测定刺梨和无籽刺梨中痕量重金属元素。     

微波消解-电感耦合等离子体质谱法测定面料中的锗含量

电感耦合等离子体质谱法具有灵敏度高、速度快、线性范围宽等优点,可用于面料中微量元素的测定。通过微波消解法消解纺织面料,采用电感耦合等离子体质谱法(ICP-MS)测定纺织面料中的锗含量,建立了微波消解-电感耦合等离子体质谱法测定面料中锗元素含量的方法。研究结果表明,锗元素在0.2~40.0μg/L范围内线性关系良好(R2=0.999 9),方法的检出限为0.02 mg/kg,不同含量加标(0.02、0.04、0.08、0.16 mg/kg)回收率在82.6%~107.8%,相对标准偏差3.0%~9.3%(n=6)。该方法具有灵敏度高、精密度好、检出限低的优点,能够用于面料中锗元素含量的测定。     

微波消解处理面制食品中铝的检测方法探究

探讨应用微波消解处理并测定面制食品中铝含量的方法。运用微波消解系统对面制食品进行消解,采用分光光度计测定样品中的铝含量。结果表明,本方法测定铝的检出限为0.23μg/ml,精密度在2.4%~9.5%,回收率为92.8%~99.7%。此实验较为简便、灵敏度高、精密度和准确度较好,适合于面制食品中铝含量的测定。     

ICP-AES法测定面制食品中的硼元素

本文研究了电感耦合等离子体发射光谱法(ICP-AES法)测定面制食品中硼砂含量的方法。采用微波消解样品,ICP-AES法测定面制食品中硼元素含量。结果表明:方法线性良好,相关系数为0.9991,检出限为0.46mg/kg,高中低3个梯度浓度加标回收率在91.7%~105.0%。该方法测定面制食品中微量的硼元素,方法简单、精密度高及准确度好。     

超级微波消解-电感耦合等离子体发射光谱/质谱法高效测定不同基质食品中27种矿物质元素

目的建立超级微波消解-电感耦合等离子体光谱法/电感耦合等离子体质谱法(inductively coupled plasma optical emission spectrometer/inductively coupled plasma mass spectrometry,ICP-OES/ICP-MS)检测10种基质食品样品的常见元素含量,分析和探究实验室中高通量快速准确检测方法。方法采用仅硝酸-水体系进行消解,ICP-MS测定重金属元素,ICP-OES测定营养元素。结果 ICP-MS测定结果表明各元素在质量浓度0~500μg/L范围内线性关系良好,相关系数为0.9997~1.0000,检出限均不高于1μg/L;ICP-OES测定结果表明各元素在质量浓度0~200 mg/L范围内线性关系良好,相关系数为0.9996~1.0000,检出限均不高于5 mg/L;标准物质验证结果均在范围内;加标实验回收率为88.1%~105.0%,相对标准偏差为0.05%~6.15%;与普通微波消解方法相比,该方法耗时缩短3/4。结论本方法准确简便、满足国标要求、适合高通量快速测定食品样品的元素含量,为科学迅速地评价食品中常见元素含量提供数据参考。     

微波消解-ICP-MS测定香椿芽中微量元素含量

建立香椿芽中Fe、Mn、Cu、Zn、Ca、Mg、Cr、Al8种元素的电感耦合等离子体质谱(ICP-MS)测定方法。采用样品微波消解,以In为内标,ICM-MS测定各元素含量。结果表明该法精密度RSD值0.98%~1.31%,回收率98.2%~101.2%,检出限0.011μg/m L~0.037μg/m L。该法灵敏、准确、快捷,符合香椿芽中微量元素测定要求。     

微波消解ICP-MS法同时测定凉茶中的六种重金属元素

建立凉茶中As、Pb、Cu、Zn、Fe、Sn等6种重金属的检测方法。微波消解凉茶样品,采用电感耦合等离子体质谱仪(ICP-MS)测定凉茶中的6种重金属元素。优化了微波消解条件和仪器测定条件。所有标准曲线的线性范围在0~100.0μg/L之间,回归方程的相关系数皆大于0.9999,方法的检出限9 ng/L~55 ng/L,加标回收率在93%~106%之间,精密度RSD小于2.1%。本方法具有快速、准确、可靠、灵敏度高及多元素同时分析等特点,可进行批量凉茶样品测定。     

电感耦合等离子体质谱法分析灵芝孢子油中的微量元素含量

食品中的微量元素分析对食品安全控制与营养评价有着重要的意义,为正确评价灵芝孢子油的食用、药用价值提供参考。取市售灵芝孢子油,运用微波消解仪消解灵芝孢子油样品,消解过程采用硝酸+双氧水酸体系预处理,减少了酸的使用,消解更完全。利用电感合等离子体质谱仪(ICP-MS)在碰撞模式下测定灵芝孢子油中24种微量元素含量。实验结果表明,灵芝孢子油中含量丰富的有益微量元素,尤其以Ca、P、Mg、Fe、K和Zn的含量居多,其次为Na、Sn、Sr、Cr、Cu、B和Mn;有害微量元素Pb、As和Hg含量符合保健食品污染物限量要求。对于所测元素,Hg的线性范围为0~1μg/L,其他元素的线性范围为0~100μg/L,仪器检出限在0.03~7.0μg/L之间,方法定量限在0.1~23.33μg/kg之间,加标回收率在84.16%~107.00%之间,相对标准偏差0.83%~4.25%(n=6)之间。研究发现该方法精密度、灵敏度高,结果可靠。     

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.