微波消解电感耦合等离子体发射光谱法同时测定水产品中铅镉铬汞砷硒有害元素的研究

研究了微波消解样品，试液用ICP－AES法同时测定样品中铅、镉、铬 、汞、砷、硒的新方法。在选定的最佳条件下测铅、镉、铬、汞、砷、硒的检出限分别为0.0008、0.0007、0.0018、0.0028、0.0012、0.0046μg/L，回收率为94．5％－104．2％，RSD为1．4％－2．6％。本法准确、快速、简便，应用于水产品的测定结果满意。     

四-（对甲基苯基）-卟啉柱前衍生，高效液柱色谱法测定食品中痕量铅、镉、汞

研究了用四-(对甲基苯基)-卟啉柱前衍生，高效液相色谱法测定食品中痕量铅、镉、汞的方法。食品样品用湿法消化后，消化液中的铅、镉、汞用四-(对甲基苯基)-卟啉(T4MPP)柱前衍生，然后用甲醇(内含0．01mol／L四氢吡咯-醋酸缓冲盐)和四氢呋喃(内含0．01mol／L四氢吡咯-醋酸缓冲盐)为流动相梯度洗脱，Waters Xterra^TMRP18(3．9150mm，5μm)色谱柱为固定相分离铅、镉、汞的T4MPP络合物，用二极管矩阵检测器检测，铅、镉、汞含量在0．01～3mg／L范围内与峰面积成线性关系，根据信噪比(S／N=3)，方法检测限为：铅2．3μg／L、镉1．8μg／L和汞2.5μg／L，方法相对标准偏差为2．1％～3．5％，标准回收率为93％～106％，该方法用于测定食品中的铅、镉、汞，结果令人满意。     

微波消解-原子荧光光谱法测定饮料中镉

目的：建立原子荧光光谱法测定果汁饮料中镉的检测方法。方法：采用微波消解法消解果汁饮料样品后，用原子荧光光谱法测定其中的痕量镉的含量，对测定条件进行了优化，并对测定方法进行了方法学考察。结果：镉的校准曲线的相关系数r=0．9995，线形范围为0-60．0μg／L，检出线为0．0472μg／L，回收率为94．9％-100．5％，RSD为5％。结论：该方法快速、简便、准确且灵敏度高，为果汁饮料中镉含量的测定提供了较好的方法，用本方法测定标准样品达到满意效果。     

冷蒸气发生-原子吸收光谱法测定纺织品中可萃取痕量镉

本文建立了以酸性人工汗液提取，冷蒸气发生-原子吸收光谱法测定纺织品中可萃取痕量镉的方法。研究了载气流速、还原剂的选择、增敏剂加入量、介质酸度以及共存离子的干扰等因素。在试验选定的最佳条件下，镉浓度在0．05μg／L～40．0μg／L呈良好线性关系，相关系数≥0．9993，方法检出限为0．020μg／L，样品加标回收率为90．8％～106．1％，相对标准偏差小于3．8％。该方法灵敏度高、操作简单、干扰小，用于纺织品中可萃取痕量镉测定，结果满意。     

胶体钯基体改进剂石墨炉原子吸收光谱法测定食盐中铅、镉

建立了胶体钯基体改进剂用于石墨炉原子吸收光谱法测定食盐中铅、镉的方法。方法采用食盐直接溶解后,以胶体钯作为基体改进剂,石墨炉原子吸收光谱法直接测定。在铅浓度为0~40μg/L、镉浓度为0~4μg/L的相关系数均0.999,铅的检出限为0.3μg/L,样品加标回收率为95.2~101.8%;镉的检出限为0.1μg/L,样品加标回收率为91.0~103.3%,相对标准偏差均5%。该方法准确、灵敏、简便,满足食盐中铅、镉的测定。     

端视ICP-AES测定蜂产品中重金属有害元素残留

采用微波消解-端视等离子体发射光谱（ICP—AES）测定蜂产品中重金属微量元素铅、镉、砷，并对ICP—AES工作参数及条件进行了优化和选择，Pb、cd、As的检出限分别为2．9×10^-3mg／L、0．056×10^-3mg／L、5．2×10^-3mg／L，线性范围为0-500μg/L，相对标准偏差范围为2．9％-8．5％；回收率范围为91％-102％。该方法与国标法比较，结果无显著性差异，能满足蜂产品测定要求。     

差分脉冲溶出伏安法检测海产品中重金属的方法学研究

建立了微波消解-差分脉冲溶出伏安法测定海产品中5种重金属的方法。采用微波消解法对样品进行消解,调节样品至中性,利用LK-4600水质重金属检测仪,采用差分脉冲溶出伏安法对样品进行测定,结果表明该方法的线性关系良好,5种重金属的相关系数r均大于0.995;检出浓度分别为铅0.1μg/L,镉0.05μg/L,铬10.0μg/L,汞5.0μg/L,砷5.0μg/L,以称样量0.5 g计,方法检出浓度分别为铅0.3μg/L,镉0.12μg/L,铬8.9μg/L,汞4.2μg/L,砷6.4μg/L;加标回收率均在90%~110%之间。     

标准加入法-抗坏血酸基体改进剂GFAAS测定腐乳中痕量铅

建立腐乳中痕量铅GFAAS测定方法。采用抗坏血酸为基体改进剂降低铅的原子化温度，分析元素在大量样品基体挥发前完成原子化；应用标准加入法，测量值在相同干扰情况下获得，两者结合能有效消除GFAAS测定腐乳中铅存在的大量样品基体干扰，使测定结果准确可靠。本方法检出限为0．05mg／kg，精密度2．3％～10．69／5，在5μg／L、10μg／L添加水平回收率为88．29／6～1169／6、97．89／5～120％。     

动力学光度法测定食品中痕量亚硝酸根

基于稀H3PO4介质中，痕量亚硝酸根对高碘酸钾氧化结晶紫的褪色反应有明显的催化作用，建立了痕量亚硝酸根的动力学光度测定法，方法检出限为0．06μg／L，线性范围为0～4．0μg／L。用于测定食品中的痕量亚硝酸根，结果与Griess法相符，6次测定结果的RSD≤5．0％。     

流动注射分光光度法测定海水中痕量的镉

建立了在Cd（Ⅱ）-碘化钾-乙基紫高灵敏度显色体系下，采用流动注射分析技术测定海水中痕量镉的新方法，并确定了该方法的最佳条件。线性范围为0．5～12μg／L，相对标准偏差RSD为1.21％（n=11，CCd（Ⅱ）=10μg／L），检出限为0．1μg／L。     

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.     

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.     

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.     

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.