果汁饮料中6种苯系物的顶空气相色谱分析

基于顶空-气相色谱分析,建立了果汁饮料中6种苯系物的检测方法。试验对色谱柱、平衡温度、平衡时间及样品基体进行了研究和条件优化。在所建立的最佳实验条件下6种苯系物的回收率在89.4%~99.5%之间,相对标准偏差(RSD)为2.8%~7.5%,方法的检测限介于2.1μg/L~9.8μg/L。     

市售饮料中7种苯系物的顶空气相色谱分析

目的:建立顶空-气相色谱法同时测定市售饮料中7种苯系物(苯、甲苯、乙苯、对二甲苯、间二甲苯、邻二甲苯和苯乙烯)含量的检测方法。方法:选用DB-FFAP(25 m×0.320 mm×0.50μm)毛细管柱分离,氢火焰离子化检测器(FID)检测,外标法定量。结果:7种苯系物在7.225 min内完全分离,相对标准偏差(RSD)在0.6%~6.3%,加标回收率在84%~112%;方法检出限在0.21~0.71μg/L;检测发现部分市售饮料中含有微量的苯系物。结论:该方法前处理简单,分析快速、精密度好、准确度高,可用于市售饮料中7种苯系物的监测分析。     

顶空-气相色谱质谱联用法测定热熔胶中的苯及苯系物

为准确测定热熔胶中苯及苯系物的含量,通过对顶空进样条件、气相色谱条件和质谱参数进行考察和优化,建立了一种用顶空-气相色谱质谱联用仪(HS-GC/MS)测定热熔胶中苯及苯系物(苯、甲苯、乙苯、对-二甲苯、间-二甲苯、邻-二甲苯和苯乙烯)的方法,并采用该方法测定了15个热熔胶样品。结果表明:1优化确定的实验条件为,0.20 g剪碎的热熔胶样品,加入1 m L含氘代苯内标(0.10 mg/L)的三乙酸甘油酯(基质校正剂),140℃下平衡30 min后顶空进样,采用键合/交联聚乙醇毛细管色谱柱在选择离子监测模式下进行GC/MS分析。2苯及苯系物的检出限在0.01～0.03 mg/kg之间,精密度和回收率分别为1.29%～3.45%和94.1%～99.9%。315个热熔胶样品中苯及苯系物均有不同程度检出,苯的检出率为13.3%,检出量0.03～0.04 mg/kg;甲苯、乙苯、对-二甲苯、间-二甲苯和邻-二甲苯的检出率均为100%,检出量分别为0.09～3.71、0.15～0.29、0.09～0.29、0.16～0.50和0.15～0.47 mg/kg;苯乙烯检出率86.7%,检出量0.14～0.71 mg/kg。该方法前处理简单、结果准确可靠,适用于热熔胶中苯及苯系物的常规检测。     

食用油中6种苯系物残留量的测定——顶空固相微萃取-气相色谱-质谱法

采用顶空固相微萃取-气相色谱-质谱技术,结合HP-INNOWAX极性毛细管柱,建立了食用油中6种苯系物的检测方法。该方法可将对二甲苯、间二甲苯分离开来,实现了6种苯系物的精确定量。在方法的测定条件下,6种苯系物峰面积与其含量呈良好的线性关系,方法检出限在0.05 mg/kg以下,加标回收率在80%～110%之间,RSD小于15%。该方法为检测食用油中苯系物残留提供了一种精确、快速、简便的分析方法。     

顶空-气相色谱法测定塑料食品包装袋中6种苯系物残留量

采用顶空-气相色谱法对食品塑料包装材料中可能残留的苯系物(苯、甲苯、邻二甲苯、间二甲苯、对二甲苯、异丙苯)进行分析。方法采用FFAP色谱柱分离,氢火焰离子化检测器FID检测,6种苯系物能够完全分离,线性较好,方法的检出限可达2.67μg/m2,7次测定相对标准偏差在0.89%～1.95%,样品加标回收率苯系物介于64.6%～97.1%。测定了10种塑料包装材料中的苯系物残留量,方法简便、快速、重现性好,完全能满足塑料包装材料中苯系物残留量的分析。     

气相色谱-质谱法检测饮料中的愈创木酚

目的建立适用于多种饮料中愈创木酚定量检测的顶空固相微萃取气相色谱-质谱检测法,用于评估饮料的风味质量。方法用顶空固相微萃取作为预处理步骤,提取饮料中的愈创木酚,在线气相色谱质谱仪定量检测。通过添加氘代愈创木酚内标,提高方法的重复性和精密度,以及抗基质干扰能力。结果本方法能实现各种饮料中愈创木酚的快速预处理和分离分析。愈创木酚浓度线性范围为0.1～50μg/L,相关系数r2为0.9982。在2.5、12.5、50μg/L3个添加水平下的回收率为99.2%～116.0%,精密度优异,相对标准偏差小于0.82%(n=9),方法定量限为0.152μg/L。结论该方法快速、灵敏度高、精密度好、重复性好,适用于多种类型饮料中愈创木酚的定量检测,为饮料风味质量的及时监控提供技术支持。     

不同菌种发酵酸奶过程中产生的苯系物的安全性分析

酸奶在发酵过程中会产生苯及苯的同系物,但是对于其产生规律和产生量一直缺乏研究。通过对比保加利亚乳杆菌和嗜热链球菌单独发酵和双菌种混合发酵,对酸奶中苯系物的产生规律和含量进行了研究,结果发现嗜热链球菌单菌种发酵比保加利亚乳杆菌单菌种发酵时苯系物的产生含量较高,苯系物产生最大值为后熟大约24 h左右,苯系物中苯乙酮最高,分别可以达到2.64±0.34 μg/L和1.95±0.22 μg/L。当使用两种菌种混合发酵时,苯及苯系物的产量高于单菌种发酵,通过比较不同配比的两种菌种的发酵结果发现嗜热链球菌:保加利亚乳杆菌=1:1时,苯系物产生量较低,其中产生量最高的甲苯为3.68±0.15 μg/L。参考饮用水的限量标准,不论是单菌种发酵还是混合发酵,酸奶中苯及苯系物的含量均低于饮用水的限量标准,因此酸奶中的苯及苯系物理论上不会对人体健康造成影响。     

顶空固相微萃取-气相色谱-质谱法测定药香型白酒中萜烯类化合物

应用顶空固相微萃取与气相色谱-质谱联用技术定量药香型白酒中的痕量萜烯类化合物。实验考察萃取头、样品酒精度、萃取温度和萃取时间对萜烯类化合物萃取效果的影响。最优顶空固相微萃取条件为将酒样稀释到酒精度10%,采用50/30μm碳分子筛/聚二乙烯苯/聚二甲基硅氧烷(DVB/CAR/PDMS)萃取头在60℃条件下萃取45min。该方法具有良好的线性,所有化合物的线性相关系数良好,R2≥0.9921,检测限为0.01～3.62μg/L,定量限为0.03～12.05μg/L,相对标准偏差小于15%,加标回收率为81.01%～118.94%。用该方法对药香型白酒的成品酒、原酒中的萜烯类化合物进行测定,共定量41种挥发萜烯类化合物,结果发现大曲香醅原酒中的萜烯总含量要多于小曲酒醅原酒中萜烯总含量,D-樟脑等17萜烯只在大曲香醅原酒中检测到,在小曲酒醅原酒中没有检测到,排除蒸馏时酸、热等带来的影响,推测这17种萜烯主要来源于大曲香醅,相反卡拉烯只在小曲酒醅原酒中检测到,推测其来源于小曲酒醅。顶空固相微萃取适合药香型白酒中的萜烯类化合物定量分析。     

冷阱捕集-气相色谱-质谱法测定卷烟主流烟气气相物中的苯系物

建立了同时选择性检测卷烟主流烟气气相物中7种苯系物(苯、甲苯、乙苯、对-二甲苯、间-二甲苯、邻-二甲苯和苯乙烯)的冷阱捕集-气相色谱-质谱联用(GC/MS)分析方法,并考察了5种不同品牌卷烟样品在深度抽吸与ISO抽吸模式下主流烟气苯系物的释放量。主流烟气气相物中的苯系物经含有内标邻-二甲苯-d10的冷甲醇吸收后在选择离子监测模式下进行GC/MS分析。结果表明:方法的检出限(LOD)和定量限(LOQ)分别为0.006和0.018μg/支,加标回收率为95.8%~110.1%,相对标准偏差(RSD)为1.1%~4.6%。深度抽吸模式下卷烟主流烟气气相物中苯系物的释放量约为ISO模式的两倍。该方法适合用于卷烟主流烟气气相物中7种苯系物释放量测定。     

分散液液微萃取-GC-MS/MS测定纺织废水中痕量4-氨基偶氮苯

建立了分散液液微萃取-气相色谱串联质谱法测定纺织废水中偶氮染料释放的痕量4-氨基偶氮苯的新方法。在碱性条件下,用连二亚硫酸钠还原纺织废水试样中的偶氮染料,再以乙腈为分散剂、三氯甲烷为萃取剂对分解生成的4-氨基偶氮苯进行分散液液微萃取,之后采用气相色谱-串联质谱法测定,内标法定量。方法优化了废水试样制备、还原反应条件、分散液液微萃取影响条件以及色谱和质谱条件等。优化的检测方法呈现良好的线性关系,线性范围为0.1～10.0μg/L;方法检出限为0.03μg/L,定量限为0.1μg/L;加标回收率为88.0%～97.0%。该方法具有操作简便、检出限低的优势,能够满足纺织废水中痕量4-氨基偶氮苯的检测。     

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.     

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.