同位素内标-超高效液相色谱-串联质谱法测定蜂蜜中氯霉素及甲硝唑

目的采用同位素内标-超高效液相色谱-串联质谱法测定蜂蜜中氯霉素及甲硝唑的残留量。方法样品经乙酸乙酯提取,MCS复合型固相萃取柱(500 mg/6 ml)净化,采用ZORBAXSB-C18色谱柱(2.1 mm×100 mm,1.8μm)分离,以甲醇和5 mmol/L乙酸铵溶液(含0.05%甲酸)为流动相进行梯度洗脱,采用电喷雾正/负离子多反应监测模式检测,同位素内标法定量。结果氯霉素、甲硝唑的浓度为0.05~5.00 ng/ml时,线性关系良好,相关系数r0.999。添加0.5、2.0、5.0μg/kg三个不同水平时,氯霉素、甲硝唑的回收率为79.3%~96.7%,相对标准偏差(RSD)为5.5%~14.8%,定量限均为0.15μg/kg,检出限均为0.05μg/kg。结论该方法灵敏度及准确度良好,可应用于日常大批量样品的高灵敏分析。     

液液萃取-液相色谱-串联质谱法测定蜂蜜中氯霉素

目的建立液相色谱-串联质谱法检测蜂蜜中氯霉素残留量的方法。方法试样前处理采用液液萃取,以甲醇 水(71 29体积分数)为流动相,用Zorbax Eclipse XDB C18柱进行分离,以氘代氯霉素作为内标,采用负离子方式,液相色谱-电喷雾串联质谱法进行测定。结果平均回收率为93.0%-98.2%,相对标准偏差小于8%。采用空白蜂蜜基质制作校正曲线,蜂蜜中氯霉素检测的线性范围为0.01-1.00μg/kg,定量检测下限为0.01μg/kg。结论方法灵敏、准确、快速,能满足蜂蜜中氯霉素的监督检测。     

固相萃取-高效液相色谱-串联质谱法测定蜂蜜中高氯酸盐

目的建立一种固相萃取-高效液相色谱-串联质谱法测定蜂蜜中高氯酸盐的含量。方法样品用酸化甲醇水提取, WAX固相萃取柱净化,经Phenyl-hexyl色谱柱分离,以电喷雾离子源在负离子多反应监测模式下进行测定,内标法定量。结果高氯酸盐的检出限和定量限分别为0.33μg/kg和1μg/kg,高氯酸盐在1～10μg/kg的加标水平内的回收率为91.6%～108.3%,相对标准偏差为2.81%～3.47%。结论该方法准确、灵敏,适用于蜂蜜中高氯酸盐的测定。     

QuEChERS-高效液相色谱-质谱/质谱法同时测定水产品中磺胺类和氯霉素类药物

目的 建立QuEChERS-高效液相色谱-质谱/质谱法同时测定水产品中磺胺类药物和氯霉素类药物含量的分析方法。方法 样品用乙腈提取, 经QuEChERS方法去脂净化后, 用甲醇和0.02%的甲酸水溶液作为流动相进行梯度洗脱, Waters Atlantis T3色谱柱进行色谱分离, 高效液相色谱-质谱/质谱电喷雾电离多反应监测正负离子模式测定, 内标法定量。结果 23种药物标准曲线的相关系数均大于0.99, 加标平均回收率为61.4%~116.2%。结论 本方法操作简单、方便高效, 可同时测定水产品中磺胺类和氯霉素类药物, 适合于实验室多项目的快速检测。     

QuEChERS-UPLC-MS/MS法测定动物源性食品中五氯酚及其钠盐

本文建立QuEChERS-UPLC-MS/MS测定动物源性食品中五氯酚及其钠盐残留量的分析方法。样品用酸化乙腈提取,QuEChERS方法净化。用甲醇和5 mmol/L乙酸铵水溶液作为流动相进行梯度洗脱,C18色谱柱分离。在超高效液相色谱-串联质谱电喷雾电离动态多反应监测负离子模式下定量分析。五氯酚在0.5～15.0 ng/mL线性范围内的相关系数为0.999 96,方法检测限为0.1μg/kg。当不同基质中的标准添加量为1.0～4.0μg/kg时,平均回收率为74.7%～101.4%。本方法操作简单、快速高效,对相关检验检测工作提供参考。     

LC-MS法测定婴儿乳粉中4种激素和氯霉素残留

建立了高效液相色谱-质谱法测定婴幼儿配方乳粉中壬基酚、双酚A、雌二醇、雌三醇和氯霉素残留的检测方法。样品经0.5%氨水的乙腈超声提取,减压浓缩后复溶于2 m L含2%氨水的甲醇溶液。以MGⅢ-C18色谱柱(4.6 mm×150 mm,1.8μm)分离,流动相为甲醇和10 mmol/L乙酸铵水溶液(0.05%氨水)(梯度洗脱),流速0.35 m L/min。采用多反应监测负离子模式,可以一次性对五种目标化合物进行定性和定量测定。在该优化条件下,检出限为0.1~0.5μg/kg,定量限为0.3~1.5μg/kg,方法回收率为80.1%~106.8%,相对标准偏差(RSD)为3.89%~9.98%。结果表明,该方法前处理简单,灵敏度高,适合于婴幼儿配方乳粉中壬基酚、双酚A、雌二醇、雌三醇和氯霉素残留的同时快速检测。     

内标液相色谱-串联质谱法测定蜂蜜中氯霉素、甲砜霉素和氟苯尼考残留

目的建立液相色谱-串联质谱法测定蜂蜜中氯霉素、甲砜霉素和氟苯尼考的分析方法。方法以氯霉素-D5为内标,样品用乙酸乙酯提取,提取液在45℃氮气吹至近干,残渣用2mL水溶解,溶解液过Oasis HLB柱净化,洗脱液在45℃氮气吹干, 50%甲醇水溶液定容,后经正己烷脱色脱脂、PSA粉末吸附净化,高速离心过膜后用串联四极杆检测。样液经过Agilent Eclipse XDB-C₁₈色谱柱分离,甲醇-水流动相梯度洗脱,多反应监测扫描模式检测。采用内标法定量。结果氯霉素在0.1~4.0μg/kg、甲砜霉素和氟苯尼考在0~40.0μg/kg呈良好的线性关系,相关系数大于0.999,回收率为93.7%~109.7%,RSD为0.7%~11.4%,检出限为0.03~0.09μg/kg,定量限为0.1~0.3μg/kg。结论该方法准确、检出限低、重现性好,适用于蜂蜜中氯霉素、甲砜霉素和氟苯尼考残留的检测。     

液质联用法测定牛奶中氯霉素类药物残留

建立了牛奶中氯霉素、甲砜霉素和氟甲砜霉素多残留的高效液相色谱-串联四极杆质谱联用测定方法。样品经碱性乙腈超声提取,以MGⅢ-C18色谱柱(2.1×150 mm,5μm)分离,流动相为10 mmol/L乙酸铵水溶液和甲醇(梯度洗脱),流速0.25 m L/min。采用多反应监测负离子模式,可以同时对牛奶中的氯霉素、甲砜霉素和氟甲砜霉素进行定性和定量测定。方法的检出限为0.1μg/kg~0.3μg/kg。在0.3、3.0、10.0μg/kg 3个加标水平下,加标回收率为80.7%~93.6%,相对标准偏差为3.85%~9.35%。     

液质联用测定蜂蜜中钩吻碱和钩吻碱子

建立一种高效液相色谱-质谱串联法测定蜂蜜中的钩吻碱和钩吻碱子的方法。样品采用1%盐酸超声提取,经MCX固相萃取小柱净化,再用氨化甲醇进行洗脱,洗脱液浓缩后用50%甲醇水溶液(含0.1%甲酸)定容,进行超高效液相色谱-质谱串联仪分析。采用乙腈和0.1%甲酸水溶液(含5 mmol/L甲酸铵)作为流动相进行梯度洗脱,质谱采用电喷雾离子源(ESI)正离子模式扫描多反应监测(MRM)对钩吻碱和钩吻碱子进行测定。该方法在30 min内完成对钩吻碱子和钩吻碱的分析。钩吻碱在28, 56和280μg/kg添加水平的回收率为89.3%～98.1%,相对标准偏差小于4.1%(n=5),方法定量限为5.6μg/kg,检出限为2.8μg/kg;钩吻碱子在20, 40和200μg/kg添加水平的回收率为86.2%～95.1%,相对标准偏差小于4.1%(n=5),方法定量限为4.0μg/kg,检出限为2.0μg/kg。该方法能快速、准确、灵敏地测定蜂蜜中的钩吻碱和钩吻碱子。     

超高效液相色谱-串联质谱法快速测定稻谷和玉米中伏马毒素

目的 建立了同位素稀释-超高效液相色谱串联质谱法测定稻谷和玉米中伏马毒素。方法 样品加入同位素内标后用50%乙腈水溶液(含1%甲酸)提取,采用ZORBAX Eclipse Plus C18 色谱柱分离,以甲醇-0.1%甲酸水溶液为流动相,梯度洗脱,质谱采用电喷雾电离,负离子模式下,以多反应监测模式(MRM)检测,内标法定量。结果 FB1,FB2和FB3在0.5~100.0μg/L范围内线性关系良好,相关系数均大于0.995,检出限均为1.0μg/kg。在5.0、50.0、500.0μg/kg三个加标浓度水平下,FB1,FB2和FB3的回收率在82.5~107.1%之间,RSD为3.9%~6.2%(n=5)。结论 该方法简单快速,定性定量准确,有效降低了背景干扰,可用于粮食中伏马毒素的检测。     

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.     

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.