同位素稀释超高效液相色谱-串联质谱法测定山楂及其口服液制品中的展青霉素

目的 建立同位素稀释超高效液相色谱-串联质谱法测定山楂及其制品中的展青霉素含量。方法 山楂口服液(山楂样品需经粉碎、果胶酶酶解处理, 乙酸乙酯提取浓缩后复溶)经多功能净化柱净化, 以乙腈-水为流动相梯度洗脱, 采用Agilent RRHD C₁₈柱(2.1 mm×100 mm, 1.8 μm), 电喷雾离子源负离子, 多反应离子监测模式(MRM)检测, 同位素稀释内标法定量。结果 展青霉素在4.934~246.7 ng/mL浓度范围内线性关系良好, 相关系数r大于0.999。在不同基质不同加标浓度下, 回收率为91.8%~105.4%, 相对标准偏差为1.8%~3.2%, 山楂检出限为3 μg/kg、定量限为10 μg/kg, 山楂口服液检出限为1.5 μg/kg、定量限为5 μg/kg。结论 该方法准确、可靠, 适用于山楂制品中展青霉素的测定。     

液相色谱-串联质谱同位素稀释法测定奶粉中双氰胺的残留

目的 建立并优化高压液相色谱-串联质谱法快速检测奶粉中双氰胺残留的方法。方法 奶粉样品经1%三氯乙酸溶液沉淀蛋白后, 通过Sep-pak AC-2离子交换固相萃取柱净化样品提取液, 去除奶粉中其他复杂基质的干扰, 浓缩后用初始流动相复溶、过膜。采用电喷雾正离子电离(ESI+)模式和多反应监测(MRM)扫描模式, 通过Acquity BEH Amide(3.0 mm×150 mm, 1.7 μm)色谱柱分离检测双氰胺目标化合物, 同位素15N4-双氰胺稀释法定量。结果 该方法在50~1200 μg/kg范围内线性良好, 相关系数r>0.998, 在三种不同基质样品中的最低检测限与最低定量限分别为2.5 μg/kg和8 μg/kg, 加标回收率为93.4%~112.3%, 相对标准偏差均<10.3%。结论 该方法简便、灵敏、精确, 不仅筛选优化了液相、质谱条件参数, 同时优化了奶粉样品的前处理方法, 适用于奶粉中双氰胺残留的检测。     

液相色谱-串联质谱法检测奶制品中9种 β-受体阻断剂药物残留量

目的 建立同时检测奶制品(牛奶、奶粉、奶酪)中9 种β-受体阻断剂(β-blockers, BBS)残留的液相色谱-串联质谱方法。方法 混合均匀的试样经β-葡糖醛苷酶/芳基硫酸酯酶水解, 乙腈提取, 硅藻土与BondElut分散固相萃取填料双重快速净化后, 利用液相色谱-串联质谱法进行定性定量分析。结果 9 种BBs在0.1~20.0 μg/L线性范围内线性关系良好(r≥0.995); 定量限(limit of quantity, LOQ, S/N≥10), 均达到0.5 μg/kg; 3 个添加水平(0.5、1.0和5.0 μg/kg)下的回收率为89.5%~112.5%; 相对标准偏差(relative standard deviation, RSD)为4.2%~11.5%。结论 该方法快速、准确、灵敏, 可用于奶制品样品中多种BBs残留的同时有效测定。     

同位素内标-高效液相色谱-串联质谱法检测牛奶及奶粉中黄曲霉毒素M1

目的 建立一种高效液相色谱-串联质谱法(high performance liquid chromatography-tandem mass spectrometry, HPLC-MS/MS)测定奶及奶粉中黄曲霉毒素M1的方法。方法 样品经甲醇溶液提取后, 经离心机离心, 上层清液用MycoSep?226 AflaZon+Multifunctional净化柱净化, 在线添加黄曲霉毒素M1同位素内标后采用LC-MS/MS进行检测。结果 黄曲霉毒素M1在0.05~5.0 μg/L范围内线性关系良好, 相关系数大于0.995; 在0.02、0.05和0.10 μg/L添加水平的回收率为89.02%~118.85%, 相对标准偏差小于7.06%(n=6), 定量限为0.06 μg/kg。结论 该方法快速、准确、灵敏, 适合用于测定奶及奶粉中黄曲霉毒素M1。     

超高效液相色谱-串联质谱法同时测定食品中的氯酸盐和高氯酸盐残留量

目的 建立了超高效液相色谱-串联质谱法测定食品中氯酸盐和高氯酸盐残留量的方法。方法 食品样品经纯水溶解,乙腈提取,固相萃取柱净化,超高效液相色谱-串联质谱测定。采用多反应监测模式,电喷雾电离源负离子模式,内标法定量。结果 氯酸盐在0~200 ng/mL、高氯酸盐在0~100 ng/mL范围内线性关系良好,相关系数(r)均大于0.99,检出限(S/N=3)为氯酸盐6.0μg/kg和高氯酸盐1.0 μg/kg,定量限(S/N≥10)为氯酸盐18.0μg/kg和高氯酸盐3.0 μg/kg。以不含氯酸盐和高氯酸盐的样品作为空白样品进行添加回收试验,氯酸盐的回收率为83.7%~106.9%,相对标准偏差(RSD)为2.9%~6.2%,高氯酸盐的回收率为87.8%~112.8%,相对标准偏差(RSD)为2.9%~7.5%。结论 该方法不但可以有效排除复杂基体的干扰,而且简单、灵敏、稳定。     

气相色谱-质谱法测定植物油中壬基酚含量

目的建立气相色谱-质谱法(gas chromatography-mass spectrometry,GC-MS)检测植物油中壬基酚(4-nonylphenol,4-NP)的分析方法,了解市售植物油中壬基酚的污染状况。方法样品加入乙腈提取液,超声提取、固相萃取柱净化、七氟丁酸酐衍生化后,采用GC-MS进行检测,同位素内标法定量。结果在线性范围5~200μg/kg内,方法回归方程为Y=7.78×10~(-3)X,相关系数为0.9991。方法的检出限为3.0μg/kg,定量限9.8μg/kg。加标回收率范围为75.7%~107.4%,相对标准偏差(relative standard deviation, RSD)为5.5%~9.7%。共检测50份市售植物油样品,其中26份植物油样品检出4-NP,检出率为52%,含量范围为3.21~28.2μg/kg,中位值为3.63μg/kg。结论此方法灵敏度较高,可用于植物油中4-NP的准确定量。检测数据表明,植物油样品壬基酚检出率较高,因此对其含量的监测不容忽视。     

婴幼儿配方奶粉中邻苯二甲酸酯的固相萃取净化-气相色谱-质谱法测定

建立婴幼儿配方奶粉中邻苯二甲酸酯(PAEs)固相萃取净化,气相色谱-质谱法测定的方法。样品加入同位素内标后,以乙腈提取,PSA/Silica固相萃取柱净化,气相色谱-质谱法检测,内标法定量。结果表明:该方法对婴幼儿配方奶粉的16种PAEs定量限为50~100μg/kg,加标回收率在74%~124%之间,RSD在0.78%~7.1%之间。该方法简便快捷,定量准确,重现性好,适用于高通量检测婴幼儿配方奶粉中PAEs质量分数。     

滤过型净化-超高效液相色谱-三重四极杆/复合线性离子阱质谱法测定草鱼肌肉冻干粉中4种硝基呋喃类代谢物

目的 建立一种基于滤过型净化柱净化,结合超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry, UPLC-MS/MS)测定草鱼肌肉冻干粉中4种硝基呋喃类代谢物的快速检测方法。方法 制备阴性草鱼肌肉冻干粉作为检测目标。样品经水解、衍生化并提取浓缩后,采用以50 mg C18为净化填料的CAFS Clean-up净化柱对复溶液进行1次快速净化,超高效液相色谱分离,三重四极杆/复合线性离子阱质谱仪进行测定,内标法定量分析。结果 4种硝基呋喃类代谢物在其相应的质量浓度范围内线性关系良好(r＞0.999),定量限为0.6~2.4 μg/kg;样品中添加定量限、2.5 μg/kg、5.0 μg/kg和50.0 μg/kg浓度水平时的平均回收率在81.3%~115.1%之间,相对标准偏差为1.5%~13.1%。结论 该方法经济、简便、高效,灵敏度高,重复性好,可作为草鱼肌肉冻干粉中4种硝基呋喃类代谢物的基体标准物质的检测方法。     

凝胶渗透色谱净化-超高效液相色谱-串联质谱法测定海带中扑草净残留量

目的 建立凝胶渗透色谱(gel permeation chromatography, GPC)净化-超高效液相色谱-串联质谱(ultra performance liquid chromatography-tandem mass spectrometry, UPLC-MS/MS)法测定海带中扑草净残留量的分析方法。方法 样品用乙腈超声提取, 经凝胶渗透色谱净化, 收集15~35 min的流出液并进行浓缩, 通过超高效液相色谱柱分离后进行质谱检测。结果 称样量为2 g时, 最佳提取条件为10 mL乙腈超声提取时间10 min; 在添加量为0.05~2.66 μg/kg范围时, 扑草净平均回收率为100.1%~102.1%, 相对标准偏差(relative standard deviation, RSD)为1.6%~2.6% (n=6); 方法检出限为0.15 μg/kg; 并将GPC与HLB、Carb-NH2固相萃取进行净化效果比较, 结果表明GPC净化更适用于海带中扑草净的净化。结论 该方法简便、快速、灵敏度高、重复性好, 可用于测定海藻类样品的扑草净残留。     

非衍生化液相色谱-串联质谱法测定茶叶中草铵膦残留量

目的 建立非衍生化液相色谱-串联质谱法直接测定茶叶中草铵膦残留的分析方法。方法 茶叶样品经水均质提取,HR-X固相萃取小柱净化,采用非衍生化液相色谱-串联质谱直接测定,电喷雾离子源负离子模式(ESI^-)下采用多反应监测模式(MRM)检测,同位素内标法定量。结果 在优化的条件下,草铵膦在5~200 μg/L范围内呈良好的线性关系,相关系数为0.9998,方法定量限(LOQ)为0.1 mg/kg。方法平均回收率为84.2%~104.9%,相对标准偏差(RSDs)低于7.6%。结论 本方法前处理简单、准确性好、灵敏度高,可用于绿茶、红茶、乌龙茶、普洱茶等茶叶中草铵膦残留量的测定。     

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.     

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.     

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.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.