毛细管电泳-电化学检测测定荞麦中表儿茶素、芦丁、槲皮素的含量

用毛细管电泳-电化学检测的方法研究了荞麦中黄酮类物质:表儿茶素、芦丁、槲皮素的含量,研究了电极电位、缓冲液的pH值、分离电压及进样时间对电泳的影响,得到优化的测定条件。以直径为300μm的碳圆盘电极为检测电极,工作电极电位为0.95V(vs.SCE),在50mmol/L硼砂(pH8.5)运行缓冲液中,上述3组分在12min内完全分离。表儿茶素、芦丁、槲皮素线性范围分别为5×10-7￣1×10-4g/mL、1×10-6￣1×10-4g/mL、1×10-6￣1×10-4g/mL;检出限分别为1.83×10-7g/mL、2.9×10-8g/mL、1.00×10-7g/mL;3种标样7次平行进样的相对标准偏差(RSD)小于2.5%;回收率表儿茶素100.4%、芦丁98.1%、槲皮素100.1%(n=3)。该法灵敏可靠,结果令人满意。     

高效毛细管电泳法检测橘皮中橙皮苷的含量

应用毛细管电泳法对橘皮中橙皮苷的含量进行了检测,研究了缓冲液的种类、缓冲液的浓度、缓冲液的pH值以及分离电压等对橙皮苷测定的影响。在pH8.0的150 mmol/L硼砂缓冲液、12 kV分离电压下,橙皮苷的测定效果最佳。毛细管电泳法测定橙皮苷的最低检测限为1.25μg/mL,加样回收率是99.75%,相对标准误差是1.98%。     

毛细管电泳-电化学发光分离检测饮料中L-赖氨酸

目的:根据L-赖氨酸(L-lysine)具有增强三联吡啶钌(Ru (bpy)32+)电化学发光信号的特性,建立一种毛细管电泳-电化学发光分离检测L-赖氨酸的新方法.方法:研究检测电位、Ru(bpy)32+浓度、进样时间、进样电压、分离电压和缓冲液pH等试验参数对L-赖氨酸检测的影响.结果:在最佳试验条件下,检测电位1.13 V;Ru( bpy)32+浓度7 mmol/L(pH 8.5);进样时间10s;进样电压12 kV;分离电压12 kV;磷酸盐缓冲液pH 8.5,8 min内可实现L-赖氨酸的分离检测,线性范围3.00～87.00 μg/mL,相关系数R=0.9991,检出限(S/N=3)为0.21μg/mL.对样品进行测定,电化学发光强度和迁移时间的RSD分别为3.85％和0.66％(n=6).结论:本法已成功用于饮料中L-赖氨酸的检测,结果令人满意.     

毛细管电泳检测发酵液中1,3-二羟基丙酮方法的建立

建立了利用毛细管电泳(CE)技术快速、准确检测发酵液中1,3-二羟基丙酮含量的新方法。所用熔融石英毛细管规格为50μm×60 cm(有效长度为45 cm),分离电压为24 kV,缓冲液为pH9.5的30 mmol/L硼砂缓冲溶液,200 nm处检测DHA。结果表明,DHA标准样品的迁移时间为8.3 min,在100μg/mL～1 000μg/mL范围内线性关系良好(R2=0.999 5),加样回收率为97.79%,RSD为1.81%。测得以甘油作为底物发酵产DHA发酵液中DHA含量为3.220g/L,此方法可有效应用于产DHA发酵过程中产物的检测。     

微乳毛细管电动色谱法检测鸡精中的3种氯丙醇

建立了微乳毛细管电动色谱分离检测3种氯丙醇的方法。考察了表面活性剂十二烷基硫酸钠(SDS)浓度、缓冲液pH及浓度、有机添加剂、助表面活性剂浓度、温度和运行电压对3-氯-1,2-丙二醇(3-MCPD)、1,3-二氯-2-丙醇(1,3-DCP)和2,3-二氯-1-丙醇(2,3-DCP)分离的影响。结果表明,最佳的微乳液组成为:3.31%(w/v)SDS,6.61%(w/v)正丁醇,0.81%(w/v)正辛烷,10%(v/v)乙腈,79.3%(v/v)5 mmol/L磷酸盐-硼砂缓冲液(pH9.0)。该微乳体系中有机溶剂乙腈对氯丙醇的分离起到了重要作用。当分离电压为20 kV、分离温度为20℃、检测波长192 nm时,3种氯丙醇在16 min内达到基线分离。3-MCPD的线性范围为2.5～500μg/mL,1,3-DCP和2,3-DCP的线性范围均为1.0～500μg/mL,相关系数均大于0.998,检出限(S/N=3)分别为0.5、0.4、0.5μg/mL。该法操作简单,灵敏度高,实验结果准确可靠,用于鸡精样品中3种氯丙醇的同时检测,结果满意。     

毛细管电泳安培检测法快速测定巧克力中的香兰素

运用毛细管电泳安培检测法研究了巧克力中香兰素的快速测定方法,研究了电极电位、缓冲液的浓度和pH、分离电压以及进样时间等因素对分离测定的影响。在30mmol/L的硼砂(pH9.24)运行缓冲液中,施加15kV的分离电压及 0.65V(vs.SCE)的电极电位条件下,铜电极对香兰素有很好的响应。香兰素在5.0×10-6～1.0×10-3g/mL范围内存在较好的线形关系,检测限为3.87×10-7g/mL(S/N=3)。对实际样品的测定,回收率为96.5%～102.8%,结果令人满意。     

毛细管胶束电动色谱分离测定大米中水胺硫磷和灭多威的残留量

用毛细管胶束电动色谱成功地分离了2种农药：水胺硫磷和灭多威。研究了电泳缓冲液的pH、浓度及表面活性剂浓度等影响因素,在选定的最佳分离条件：pH7.0,20mmol/L硼砂缓冲溶液＋70mmol/LSDS＋20%甲醇,20kV分析电压,检测波长214nm下,二组份在12min内得到基线分离。检测限分别为：水胺硫磷1.2μg/mL和灭多威0.9μg/mL。同时用该方法对通辽地区的大米样品进行了抽检,抽检结果表明：开鲁县大米样品中水胺硫磷和灭多威的残留量最高;科左后旗的大米样品中未检测到水胺硫磷和灭多威这两种农药。     

非水胶束电动毛细管色谱在线富集测定果蔬中克百威和甲萘威残留

建立基于非水胶束电动毛细管色谱在线富集技术测定蔬果中克百威和甲萘威残留的新方法。对影响分离和富集效果的缓冲液参数、分离电压和进样时间进行优化。运行缓冲溶液为含100mmol/L十二烷基硫酸钠、30mmol/L乙酸钠的甲酰胺-乙腈(85:15,V/V)溶液,表观pH值为9.4;分离电压20kV;进样时间150s。在此优化条件下,克百威和甲萘威的富集倍数分别为678和758倍;检出限分别为31μg/L和7.9μg/L;6次重复测定的峰面积相对标准偏差为2.47%、1.76%;平均加标回收率为80.4%～96.2%和92.5%～104.1%。以上结果表明该方法具有良好的灵敏度和重现性,可用于果蔬中该两种农药残留的检测。     

加压毛细管电色谱法分离检测薯片中丙烯酰胺的含量

建立加压毛细管电色谱法检测薯片中丙烯酰胺含量的方法。该方法采用EP-100-20/45-3-C18毛细管色谱柱（总长度45?cm,有效长度20?cm,直径100?μm,ODS填料3?μm）进行分离,并对流动相中有机相比例、磷酸盐缓冲溶液浓度、分离电压等实验条件进行考察和优化。结果表明：在流动相为乙腈-15?mmol/L?NaH2PO4（pH?4.7）缓冲盐溶液（15∶85,V/V）,流动相流速为0.04?mL/min,分离电压为－2?kV,紫外检测波长为202?nm的条件下,薯片中的丙烯酰胺得到了良好地分离。方法在2.0～32?μg/mL范围内线性关系良好,相关系数为0.999?4。丙烯酰胺检出限（RSN=3）为0.30?μg/mL,平均回收率为95.3%～108.1%,相对标准偏差低于1.48%。该方法已经用于薯片中丙烯酰胺含量测定,结果良好。     

反相高效液相色谱法测定刺梨中芦丁和槲皮素的含量

建立反相高效液相色谱法测定刺梨中芦丁和槲皮素的含量。采用WatersSunfire ODS C18色谱柱(4.6 mm×150 mm,5μm),流动相为甲醇-0.2%磷酸缓冲溶液(60:40),流速1.0 mL/min,检测波长360nm,柱温30℃,进样量10μL。结果表明,在上述色谱条件下,芦丁和槲皮素良好分离,质量浓度分别在2~100μg/mL(R2=0.9991)和1~100μg/mL(R2=0.9992)之间线性关系良好。平均加标回收率分别为98.27%和99.15%,相对标准偏差(RSD)分别为2.98%和3.76%,重现性实验RSD分别为芦丁2.18%(n=5),槲皮素1.76%(n=5)。测得刺梨中芦丁和槲皮素的平均含量分别为7.070mg/g和1.352mg/g。RP-HPLC法简便快捷、灵敏,结果准确,可用于刺梨中黄酮成分含量的检测。     

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.     

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.