高效液相色谱-紫外检测法快速测定小麦面粉中偶氮甲酰胺

建立小麦粉中偶氮甲酰胺的高效液相色谱快速检测法。方法 样品经二甲亚砜-丙酮混合溶剂超声振荡提取,采用Hypersil-C₁₈色谱柱(250 mm×4.6 mm,5 μm),流动相为10 mmol/L H₂SO₄水溶液,流速为1 ml/min,检测波长为275 nm,进样量20 μl,二极管阵列检测器定量。结果 偶氮甲酰胺在0.01～1.00 mg/ml范围内呈良好线性关系,相关系数r=0.999 2,RSD<4.3%,平均回收率为95.9%;山东地区85份样品偶氮甲酰胺含量检测结果均小于检出限,符合现行限量标准。结论 本方法准确可靠,方便快捷,灵敏度高,适合于大批量小麦粉中偶氮甲酰胺的检测。     

亚甲基蓝褪色光度法测定小麦粉中的痕量溴酸钾

利用KBrO₃在H₂SO₄介质中能氧化褪色亚甲基蓝的特性,建立了亚甲基蓝褪色光度法测定小麦粉中痕量KBrO₃的新方法。试验结果表明,在测定波长为665 nm,2.0 mol/L H₂SO₄溶液为1.7 ml,0.05 g/L亚甲基蓝用量为1.5 ml,1.0%KBr用量为2.0 ml,加热温度为60℃,反应时间为5 min条件下,该方法的线性范围为0.06～0.50 mg/L,检出限为0.01 mg/kg,定量限为0.03 mg/kg。该方法用于小麦粉中痕量KBrO₃的测定,样品回收率在94.3%～105.7%,相对标准偏差RSD＜5%,试验结果能满足小麦粉中痕量溴酸盐测定的要求。      

凝胶渗透色谱-高效液相色谱法测定火麻仁油中Δ9-四氢大麻酚含量

目的 建立使用凝胶渗透色谱(GPC)净化,高效液相色谱(HPLC)分析测定火麻仁油中Δ⁹-四氢大麻酚(Δ⁹-THC)的检测方法。方法 样品经环已烷和乙酸乙酯溶解,经GPC净化分离,再以Agilent Eclipse XDB-C₁₈色谱柱(150 mm×4.6 mm,3 μm)分离,以乙腈-水流动相洗脱,二级管阵列检测器分析,外标法定量。结果 该方法在0～500 μg/L浓度内,线性相关系数(r)＞0.999,方法检测限(LOD)为0.05 mg/kg,定量限(LOQ)为0.17 mg/kg。加标回收率在84.6%～101.8%之间,相对标准偏差为3.2%～4.7%(n=6)。在实际样品检测中,10种不同品牌的火麻仁油中Δ⁹-THC含量在0.40～5.82 mg/kg之间。结论 该方法稳定性好,灵敏度高,适用于火麻仁油样品中Δ⁹-THC的检测分析。     

盐析辅助均相液液萃取-高效液相色谱法测定蔬菜水果中对苯基苯酚残留

建立了盐析辅助均相液液萃取结合高效液相色谱法测定蔬菜水果中对苯基苯酚残留的检测方法。试样经乙腈提取,用氯化钠盐析分层,以五氟苯基柱为色谱分离柱,甲醇-水为流动相梯度洗脱,二极管阵列/荧光双检测器,外标法定量。对提取溶剂、提取盐体系、净化、浓缩方法和稳定性等前处理的关键因素都进行了优化,并考察了不同色谱柱和流动相条件对分离效果的影响。结果表明,对苯基苯酚在0.05~100.00 µg/mL（二极管阵列检测器）和0.01~5.00 µg/mL（荧光检测器）范围内线性关系良好,相关系数（R2）均大于0.999,紫外和荧光条件下检出限分别为0.03 mg/kg和0.01 mg/kg,定量限分别为0.10 mg/kg和0.02 mg/kg。在3个空白添加浓度水平（LOQ、2LOQ和10LOQ）,平均回收率分别为82.28%~110.7%和85.83%~109.8%,相对标准偏差（RSD）分别为2.60%~5.72%和2.66%~5.26%。该方法简便快捷、准确性和重现性较好,二极管阵列/荧光双串联检测可相互定性,特异性较好,适用于蔬菜水果中对苯基苯酚残留的测定。     

超高效液相色谱法同时测定保健品中4种大豆异黄酮

目的：建立超高效液相色谱法同时测定保健品中大豆苷(Daidzin)、染料木苷(Genistin)、染料木素(Daidzein)和大豆素(Genistein)4种大豆异黄酮。方法：样品用80%甲醇超声提取后,以甲醇-0.1%磷酸水(V/V)作为流动相梯度洗脱分离,使用二极管阵列检测器(Photo-diode Array, PDA)于260 nm波长下测定。结果：4种大豆异黄酮在1.0~50 mg/L范围内,标准曲线线性良好,相关系数R²均大于0.999。平均回收率为86.7%~106%,相对标准偏差RSDs为1.31%~6.32%。方法检出限为0.5~1.0 mg/kg,方法定量限为1.5~3.0 mg/kg。结论：方法学实验结果表明,该方法回收率高,灵敏度高,且操作简单,快速高效,可应用于实际样品测定。     

通过式固相萃取-高效液相色谱法测定小麦粉及面粉处理剂中的硫脲

目的 建立通过式固相萃取柱净化,高效液相色谱法测定小麦粉及面粉处理剂（FTA）中硫脲的分析方法。方法 试样中的硫脲经乙腈-水溶液（8：2,V/V）提取,通过式固相萃取柱PRiME HLB净化,XBridge Amide色谱柱（4.6 mm×250 mm,5 μm）分离,乙腈-水为流动相梯度洗脱,二极管阵列检测器（DAD）检测,外标法定量。结果 该方法在0.05~20 μg/mL浓度范围线性关系良好,相关系数（R²）>0.999;检出限（LOD,S/N≥3）为0.15 mg/kg,定量限（LOQ,S/N≥10）为0.5 mg/kg;在空白小麦粉和FTA中进行3个加标水平（LOQ、2LOQ、10LOQ）的加标回收实验,方法的平均回收率在95.5%~103.7%之间,相对标准偏差（RSD）<5.7%。结论 该方法解决了酶式FTA易胶化分散效果差的问题,同时有效去除了小麦粉及FTA中的基质干扰,保护了色谱柱。该方法简单、灵敏、准确,适用于小麦粉及FTA中硫脲的准确定性、定量分析。     

高效液相色谱法对小麦粉及其制品中硫脲的测定

旨在建立一种测定小麦粉及其制品中硫脲的高效液相色谱检测方法：小麦粉和挂面样品中的硫脲经纯水在25 ℃条件下超声提取15 min后，经离心、过滤后，由Agilent ZORBAX SB-C18色谱柱分离，流动相为0.02 mol/L磷酸-磷酸二氢铵缓冲溶液（pH=3）+甲醇=98+2，二极管阵列检测器，检测波长为236 nm，外标法定量。硫脲在0~20.0 μg/mL范围内，线性关系良好（相关系数r=0.999 99），方法检出限（S/N=3）为0.5 mg/kg，定量限（S/N=10）为1.5 mg/kg。小麦粉及挂面样品均在方法检出限、2倍方法检出限、10倍方法检出限3个水平进行了加标回收率实验和精密度实验，实验结果均符合GB/T 27404—2008《实验实验室质量控制规范 食品理化检测》附录F中对加标回收率和精密度的要求。该方法准确、稳定可靠，能够满足小麦粉及其制品中硫脲的测定。     

电感耦合等离子体质谱法测定乳制品中硒含量

本研究建立以甲醇为基体改进剂内标校正外标定量的电感耦合等离子体质谱法检测乳与乳制品中微量元素硒的含量。本研究采用微波消解前处理方法,使用电感耦合等离子体质谱仪的碰撞反应模式,内标中添加甲醇溶液为基体改进剂,通过分析微量元素硒的6个同位素的灵敏度和线性相关性,确定选择质量数 _⁷⁸Se 测定乳制品中的硒。同时用Minitab 中的DOE实验设计进行分析,采用 _⁷²Ge元素作内标补偿基体效应,最终以 7.5 %(V/V)的甲醇作为基体改进剂,有效的控制了硒的回收率；本研究的方法检出限为固体样品0.00737mg/kg,液体样品0.00264mg/kg,5种不同基质样品的精密度(RSD,n=6)在2.0 %～6.1 %之间,加标回收率为 81.1 %～117 %。该检测方法快速简便,精密度高,准确性好,也具有较高的灵敏度,可为乳及乳制品中微量元素硒的测定提供参考。     

X-射线荧光光谱仪快速筛查大米中镉的含量

建立X-射线荧光法测定大米中镉含量的分析方法。方法 样品经粉碎后,压片,直接置于仪器上测定25 min。结果 仪器方法检出限和定量限分别为0.035和0.094 mg/kg;准确度标准偏差为0.015 5,t_d=0.30,重复性χ²=5.32,12 h内仪器稳定性χ²=11.07,随机两台仪器测定结果的标准偏差为0.021 3。结论 X-射线荧光光谱仪检出限和定量限能够满足大米中镉的检测的标准要求,仪器准确度、重复性和稳定性符合快速测定要求,X-射线荧光法为大米中镉的快速筛查提出了新方法,同时为基层粮库稻米收购,食品原料验收和监管提供了技术支撑。     

高效液相色谱法测定饮料中10种防腐杀菌剂

建立了同时测定饮料中10种防腐杀菌剂的高效液相色谱-二极管阵列检测器(HPLC-DAD)测定方法。方法 样品用甲醇提取,通过C₈固相萃取柱净化,以甲醇-0.02 mol/L乙酸铵为流动相,经C₁₈反相色谱柱(250 mm×4.6 mm,5.0 μm)分离,二极管阵列检测器检测,外标法定量。结果 10种防腐杀菌剂在0.1～10.0 μg/ml范围内线性关系良好(r≥0.995 1),检出限为0.25～1.0 μg/ml(S/N=10),10种防腐杀菌剂在两种饮料基质(果汁饮料、碳酸饮料)中添加3个水平的样品中的回收率74.1%～94.1%;相对标准偏差为5.3%～15.1%。结论 该方法操作简单、快速、检出限低,满足国内外对饮料类食品中上述10种防腐杀菌剂的限量要求,适用于饮料中10种防腐杀菌剂的检测。     

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.