MP-AES法测定皮革和纺织品中可萃取重金属含量

采用微波等离子体原子发射光谱法(MP-AES)测定皮革和纺织品中9种可萃取重金属的含量。样品经过人工酸性汗液萃取,MP-AES测定其As、Cd、Co、Cr、Cu、Hg、Ni、Pb、Sb的可萃取含量。结果表明:方法检出限在0.004～0.330mg/kg之间,加标回收率在89%～108%之间,相对标准偏差小于1.5%。该方法操作简便,可实现多种元素同时测定,检出限低、线性范围宽并具有良好的准确度和精密度,与ICP-OES法具有极佳的吻合性,适用于皮革和纺织品中可萃取重金属含量的检测。     

温度控制对微波萃取叶黄素酯的影响

探索温度控制对微波辅助萃取叶黄素酯萃取率的影响。首先测定不同输出功率对萃取溶媒升温的影响,然后以万寿菊干花颗粒为样品,探讨升温功率、萃取时间和萃取温度对萃取率的影响,并比较相同温度条件下微波萃取与溶剂法的萃取率。结果表明：分子中含有O－H键的溶媒升温较快;升温功率的变化对萃取率的影响有限。萃取时间的延长可导致萃取率下降;在1600W、20min和分别为50、50、40℃条件下,正己烷、乙酸乙酯和四氢呋喃萃取率分别为83%～95.23%、81.44%～96.59%和91.72%～94.40%。在相同温度条件下,微波萃取可有效地提高叶黄素酯的萃取率。     

ICP-MS法测定医用口罩中可萃取重金属

为测定医用口罩中12种可萃取重金属含量，样品采用酸性汗液进行萃取，内标法定量，电感耦合等离子体质谱法（ICP-MS）进行测定。结果表明，各重金属元素在相应的浓度范围内呈良好的线性关系，相关系数为0.998 6～0.999 9，检出限为0.000 1～0.002 mg/kg，精密度RSD为2.6%～5.1%，回收率为80.8%～95.8%。该方法准确、可靠、灵敏度高，适用于医用口罩中12种可萃取重金属的测定。     

ICP-MS测定毛纤维废纺织原料中可萃取重金属

通过固相萃取-集成式碰撞反应池-电感耦合等离子体质谱法（iCRC-ICP-MS），测定毛纤维废纺织原料样品中10种可萃取重金属元素（Cr、Co、Ni、Cu、Zn、Pb、Cd、Sb、As、Hg）含量。使用模拟人工汗液对废纺织原料样品进行浸提，浸提液经过固相萃取、分离富集，去除人工汗液中高盐基质对重金属元素检测的干扰。利用内标法和集成式碰撞反应池技术，校正基质效应和质谱干扰。试验结果表明：所检测的10种元素线性关系良好，相关系数R2均≥0.999 0，方法检出限为0.003～0.030 mg/kg；在加标水平下，毛纤维废纺织原料样品加标回收率在86.5%～109.1%，精密度为1.6%～5.8%；该方法分析灵敏度高，适用于毛纤维废纺织原料中可萃取重金属元素的分析。     

电感耦合等离子体发射光谱法测定生态纺织品中可萃取重金属的含量

采用人工酸性汗液进行样品预处理,应用电感耦合等离子体发射光谱法测定生态纺织品中可萃取重金属Pb、Cd、Hg、As、Cr、Co、Ni、Cu和Sb等元素的含量.研究了共存元素对被测元素的影响,选择了适合的分析谱线及工作参数;同时进行了方法检测限、精密度和准确度试验.该方法相对标准偏差小于5%,元素的回收率为91.4%～108.6%,能简单、快速、准确、可靠测定生态纺织品中的可萃取重金属含量.     

双水相萃取分离葡萄籽中原花青素

采用双水相萃取葡萄籽中原花青素,首先研究双水相萃取体系组成、辅助萃取方法、萃取策略对原花青素萃取效果的影响,并采用正交试验对原花青素萃取条件进行优化。结果表明,双水相萃取体系组成为无水乙醇/硫酸铵,辅助萃取方法为微波辅助法,萃取策略为乙醇+水+葡萄籽微波处理后加入硫酸铵,条件为无水乙醇/硫酸铵萃取体系为质量分数30%无水乙醇/质量分数20%硫酸铵,加入葡萄籽质量分数为3%,pH为4.0,微波功率100 W,微波时间5 min,在该条件下,葡萄籽中原花青素的萃取率为94.1%,得率为25.8mg/g;     

超临界CO2和微波辅助萃取佩兰挥发油工艺的研究

本文通过超临界CO2萃取均匀设计实验和微波诱导萃取佩兰挥发油的正交实验比较,考察影响提取的主要因素,寻求最佳萃取工艺。超临界CO2萃取最佳工艺条件为萃取压力15MPa,萃取温度32℃,CO2流量20kg/h和时间80min,得率2.71%;微波萃取最佳工艺条件为辐射功率720W,辐射时间160s,溶剂量300ml,洗涤剂量30ml,得率3.76%。水蒸馏法提取率为0.76%。结果表明超临界CO2和水蒸馏法萃取佩兰挥发油品质最好;微波萃取收率最高,但品质较差。     

ICP-MS法测定纺织品中可萃取重金属方法探讨

以GB/T18885—2009中规定的9种重金属元素为对象,采用电感耦合等离子体质谱(ICP-MS)法测定纺织品中可萃取重金属含量。介绍了如何优化仪器条件,采用合适的内标物和同位素,并通过比较分析得出试验溶液最合适的稀释倍数,从而为大批量、简便、高准确性检测纺织品中可萃取重金属含量提供条件。     

超临界CO2和微波萃取茶叶籽油工艺研究

通过微波萃取和超临界C02(SC-C02)萃取茶叶籽油的正交试验,考察影响萃取效果的主要因素,探讨最佳萃取工艺条件.超临界C02萃取的优化工艺条件为:萃取压力35MPa、萃取温度45℃、萃取时间80min、分离温度30℃、C02流量25～35kg/h,原料粉碎度40目,在此条件下油脂得率为28.07%.微波萃取优化工艺条件为:以环己烷为萃取剂,原料粉碎度40目,溶剂与物料质量比值为5.0,微波功率700W,每次微波辐射时间50s,微波累计辐射6次,在此条件下油脂得率为27.16%.并比较不同提取方法对油脂得率和油脂品质的影响.结果表明,微波萃取所需时间较短,超临界C02萃取所得茶叶籽油的品质较优,是提取优质茶叶籽油的首选方法.     

微波和超临界CO2萃取杜仲籽油工艺研究

通过微波萃取和超临界CO2萃取杜仲籽油的正交试验,考察影响萃取效果的主要因素,寻求最佳萃取工艺条件。微波萃取最佳工艺条件为:以环己烷为萃取剂,原料粉碎度40目,溶剂与物料质量比值为5.0,微波功率700W,每次微波辐射时间50s,微波累计辐射8次,在此条件下油脂得率为27.07%。超临界CO2萃取的最佳工艺条件为:萃取压力35MPa、萃取温度45℃、萃取时间70min、分离温度30℃、CO2流量25～30kg/h,原料粉碎度40目,在此条件下油脂得率27.76%。并比较不同提取方法对油脂得率和油脂品质的影响。结果表明,微波萃取所需时间最短,油脂得率较高;超临界CO2萃取所得杜仲籽油的品质最优,是提取优质杜仲籽油的首选方法。     

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.     

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.     

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.     

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.