QuEChERS-超高效液相色谱-串联质谱法同时测定枸杞子中65种农药残留

目的 采用多壁碳纳米管改进的QuEChERS-超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry, UPLC-MS/MS)建立一种能够快速、稳定地同时测定枸杞子中65种农药残留的分析方法。方法 样品经粉碎后,加水溶胀,乙腈萃取,多壁碳纳米管净化, Waters Acquity UPLC BEH C₁₈柱(100 mm×2.1 mm, 1.7μm)分离,以2 mmol/L醋酸铵水混合溶液(含0.1%甲酸, V/V)-2 mmol/L醋酸铵甲醇混合溶液(含0.1%甲酸,V/V)为流动相进行梯度洗脱,采用电喷雾正离子多反应监测模式进行分段扫描。选择阴性有机枸杞子作为空白基质,基质匹配外标法对65种农药残留进行定量分析。结果 65种农药在线性范围内线性关系良好,线性相关系数在0.9962～1.0000之间,方法的检出限为0.5～5.0μg/kg,定量限为1.0～10.0μg/kg,加标回收率为65.9%～117.0%,相对标准偏差为2.9%～13.0%。采用该方法对不...     

改进的QuEChERS-GC-MS法快速分析茶叶中30种农药残留

本文建立了茶叶中常用的30种农药的快速分析方法。以0.1%乙酸的乙腈(V/V)作为溶剂,Agilent SampliQ提取试剂对样品进行1min提取后,用C18和Agilent SampliQ净化试剂净化,用10ml0.1%乙酸的乙腈与甲苯(体积比3:1)洗脱,气相色谱-质谱(GC-MS)检测。30种农药的检测限(LOD)为0.03μg/kg(氟草胺)～13μg/kg(苯胺灵)。采用内标法定量,添加回收试验结果表明,30种农药的平均回收率为74%～108%,相对标准偏差为0%～10.38%。该方法的灵敏度、准确度和精密度均符合农药残留测定的技术要求。     

QuEChERS-超高效液相色谱-串联质谱法测定桑叶中64种农药残留

目的建立Qu ECh ERS结合超高效液相色谱-串联质谱法测定桑叶中64种农药残留的方法。方法样品经乙腈提取,应用Qu ECh ERS方法进行净化处理。使用Cortecs T3 (2.1 mm×100 mm, 2.7μm)色谱柱,用含0.1%(V/V)甲酸溶液(A)和甲醇(B)为流动相进行梯度洗脱,采用电喷雾电离(electrospray ionization,ESI)和多离子检测模式(multiple reaction monitoring, MRM)进行检测,基质外标法定量。结果 64种农药在0.001~0.050 mg/L范围内线性良好,线性相关系数均大于0.999。在1~10μg/kg添加浓度范围内,回收率为78.0%~94.9%,相对标准偏差为1.1%~5.5%。结论该方法操作简单,灵敏度高,可用于桑叶中农药残留的高通量筛查。     

超快速液相色谱-串联质谱法测定生鲜蔬菜中22种农药残留

采用超快速液相色谱-串联质谱法,建立生鲜蔬菜中22种多农药残留的快速检测方法。蔬菜样品经含0.1%乙酸的乙腈溶液提取、盐析后直接吸取上清液,以甲醇-水作为流动相体系,在电喷雾正离子化模式下,利用三重四极杆质谱仪,在多反应监测模式下测定。试验结果表明:22种农药在0.1～200 μg/L的浓度范围内呈良好的线性关系,线性相关系数均0.99,检出限范围为0.4～1.2 μg/kg,定量限范围为1.2～4.0 μg/kg。22种农药的平均回收率(n=5)范围为79.1%～117%,相对标准偏差(RSD)小于10%。该方法快速、灵敏度高,能够满足生鲜蔬菜中多农药残留的快速检测分析要求。     

气相色谱-串联质谱法同时检测梨中34种农药残留量

目的建立气相色谱-串联质谱法同时检测梨中34种农药残留量(包括有机磷、有机氯和拟除虫菊酯类农药)的方法。方法匀浆后的样品经乙腈(含1%乙酸)溶液提取,N-丙基乙二胺(primary secondary amine,PSA)净化,无水硫酸镁脱水,氮吹浓缩后,采用气相色谱-串联质谱多反应离子监测(multi reaction monitor,MRM)方法检测,外标法定量。结果 34种农药在0.001~0.1μg/m L的线性范围内均呈现良好的线性关系(r2为0.9973~0.9993)。0.01、0.10 mg/kg加标浓度下,各农药的平均回收率为83.3%~109.4%,相对标准偏差为1.3%~10.8%,该方法定量限为5.0μg/kg。结论该方法灵敏度高,准确性好,简便快速,适用于梨中多种农药残留量的检测。     

液相色谱-串联质谱法测定水果中6种植物生长调节剂残留量

目的研究同位素内标-液相色谱-串联质谱测定水果中6种植物生长调节剂的方法。方法样品经含1%乙酸的乙腈提取,采用Welch Xtimate C18色谱柱(2.1 mm×100 mm,3μm),乙腈-0.01%氨水(含2 mmol/L乙酸铵)为流动相,梯度洗脱,多反应离子监测(MRM)模式,分段ESI+与ESI-扫描方式检测。结果 0.6、10和50μg/kg三个浓度的样品加标试验,回收率为80.1%~115.0%,相对标准偏差为4.3%~9.9%,定量限和检出限分别在0.2~4.0和0.06~1.5μg/kg。结论建立的分析方法简便、准确、灵敏,满足食品中农药最大残留限量要求。     

分散固相萃取-气相色谱-串联质谱法测定输印尼大蒜中5种农药残留

印尼颁发的农业部长4号令对我国大蒜出口造成了严重影响。利用改进的QuEChERS技术为前处理方法,优化了净化吸附剂的用量,建立了输印尼大蒜中5种农药残留的检测方法。样品中加入无水乙酸钠和正己烷饱和的乙腈(含0.1%乙酸)溶液,振荡后过滤,滤液经旋转蒸干,色谱纯乙腈洗脱、PSA-C18吸附剂组合净化,过滤膜后用气相色谱-串联质谱测定。结果表明,在(0.1~1500)μg/L范围内,5种农药的浓度与峰面积呈良好的线性关系,相关系数均大于0.99,仪器的检出限为(0.1~100)ng/m L,方法的定量限为(0.025~25)μg/kg。5种农药在各自3个添加水平下,在大蒜中的平均回收率在84.3%~111.3%,相对标准偏差RSD为1.9%~6.7%。结果表明利用该方法能快速准确地对输印尼大蒜进行分析,满足输入国的要求。     

液相色谱-串联质谱法测定猪肉中13种磺胺类药物残留

利用液相色谱-电喷雾串联质谱建立猪肉中13种磺胺类药物残留的同时、快速分析方法.猪肉样品中的残留药物用1%乙酸-乙腈均质提取,浓缩后用0.1%甲酸-乙腈定容,并用正己烷液-液分配除脂后,用Kinetex C18色谱柱(100mm×2.1mm,2.6μm)分离,以0.1%甲酸-乙腈作为流动相梯度洗脱,采用电喷雾正离子电离,多反应监测模式检测,基质匹配外标法定量.13种磺胺类药物在1~300μg/kg范围内线性关系良好,定量限均小于10μg/kg.在1、2μg/kg和10μg/kg这3个添加水平下,回收率在60.0%~78.1%之间,相对标准偏差(RSD)在0.24%~8.88%之间.此方法操作简便,灵敏度、准确度、精密度均满足残留分析的要求.     

UPLC-MS/MS法同时测定蔬菜中34种农药残留

采用超高液相色谱-串联质谱联用仪(UPLC-MS/MS)技术建立了同时检测蔬菜中34种农药多残留量的快速检测方法。样品经乙腈提取,浓缩定容后用Qu ECh ERS农残净化管净化,Acquity BEH-C18超高液相色谱柱分离,进入电喷雾串联四极杆质谱进行检测,采用多反应监测(MRM)分析,对液质分离条件进行优化。结果表明34种农药在10 ng/m L~200 ng/m L范围内线性良好(r≥0.993 6)。在10μg/kg~30μg/kg范围内,平均加标回收率在68.7%~116.8%之间,RSD≤12%。该方法检出限为0.001 mg/kg~0.01 mg/kg,测定结果满足蔬菜样品中多残留农药的检测要求。     

QuEChERS-高效液相色谱-串联质谱法测定毛豆中常用21种农药残留

目的建立液相色谱-串联质谱法同时检测毛豆中21种常用农药残留的分析方法。方法样品以乙腈-甲酸(99:1,V:V)作为提取剂,经Qu ECh ERS方法前处理,采用Phenomenex的Kinetex C_(18)色谱柱(50 mm×2.1mm,2.6μm,100?)分离,以乙腈-0.1%甲酸水溶液为流动相梯度洗脱,以电喷雾电离(ESI)、正离子模式和负离子模式2种多反应监测(MRM)模式检测,外标法定量。结果 21种农药在5~200 ng/m L范围内,线性相关系数均大于0.99,线性良好。分析目标物添加水平为0.01~0.10 mg/kg时,回收率范围为73%~113%,RSD范围为1.3%~10.9%,符合残留分析的要求。21种农药的定量下限为0.01 mg/kg。结论该方法的提取简便,基质分散效果好,灵敏度满足国内外限量标准的要求,适合毛豆中常用农药残留的同时测定。     

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.