离子交换固相萃取-超高效液相色谱-串联质谱法快速测定腐竹中的乌洛托品

目的建立腐竹中乌洛托品的超高效液相色谱-串联质谱(UPLC-MS/MS)测定方法。方法样品经乙腈/水(1:1,v:v)溶液超声提取,阳离子交换柱净化后,经Waters Acquity UPLC BEH HILIC(2.1 mm×100 mm,1.7μm)色谱柱分离,在电喷雾正离子多反应监测模式下进行测定。结果乌洛托品在0.5~100.0μg/L范围内线性关系良好,相关系数(r)大于0.999。方法检出限和定量限分别为6μg/kg和20μg/kg。在20、40、100μg/kg 3个空白加标水平下,乌洛托品的加标回收率为100.1%~103.9%,相对标准偏差为4.7%~8.9%。结论该方法快速、简便、准确可靠,适用于腐竹中非法添加的乌洛托品的含量测定。     

QuEChERS-超高效液相色谱-串联质谱法测定水果中高氯酸盐

目的 建立一种测定水果中高氯酸盐的超高效液相色谱-串联质谱的分析方法。方法 水果经乙腈-水(1:1, V:V)提取, C18和GCB净化后, Waters Torus DEA色谱柱(2.1×100 mm, 1.7 μm)色谱分离, 0.9%(v/v)甲酸乙腈- 50mmol/L甲酸铵(pH 2.9)溶液进行梯度洗脱, 电喷雾负离子模式下, 多反应监测(MRM)方式进行测定, 内标法定量。结果 实验表明, 高氯酸盐在0.5~20 μg/L浓度范围内呈良好的线性关系, 相关系数r=0.9987, 方法检出限为0.8 μg/kg, 定量限为2.5 μg/kg。在浓度分别为10、20、100 μg/kg加标水平下, 高氯酸盐的回收率范围为87.7%~102%, 相对标准偏差小于6.1%。结论 该方法简单快捷、准确可靠, 适用于水果中高氯酸盐的测定。     

超高压液相色谱-串联质谱法测定腐竹、米线、年糕中的乌洛托品

目的 建立腐竹、米线、年糕中乌洛托品的超高压液相色谱-串联质谱分析方法。方法 样品经粉碎后, 用乙腈提取, MCX小柱净化, Waters ACQUITYTM UPLC BEH HILIC色谱柱分离, 最后在电喷雾正离子多反应监测模式下, 用超高压液相色谱-串联质谱仪进行分析。结果 乌洛托品在1.00～100.00 μg/L的范围内呈现良好的线性关系良好, 线性方程为Y=2391.11X+253.197, R2大于0.99。该方法检出限(S/N=3)和定量限(S/N=10)分别为0.30 μg/kg 和1.00 μg/kg。在1.00、10.00、50.00 μg/kg三个添加水平下, 乌洛托品平均回收率为82.0%～107.0%, 相对标准偏差为6.3%～15.6%。结论 该方法操作简便、检出限低, 能够满足腐竹、米线、年糕中乌洛托品检测的要求。     

稳定性同位素稀释-超高效液相色谱串联质谱法测定腐竹中的乌洛托品

采用超高效液相色谱-串联质谱法(UPLC-MS/MS)和稳定性同位素稀释技术,建立了测定腐竹中乌洛托品的分析方法。以乙腈为提取溶剂,向腐竹样品中加入乌洛托品的稳定性同位素,经固相萃取柱净化,采用HILIC色谱柱分离,目标物在UPLC-MS/MS的多反应监测(MRM)模式下,内标法定量。该方法在1~40μg/L范围内有良好的线性关系,相关系数为0.9996,方法定量限为2μg/kg。在添加水平为2、10、30μg/kg时,平均回收率为97.8%~101.5%,相对标准偏差(RSD)为1.9%~4.8%。本方法灵敏度高,准确度和重复性好,可为作为检测腐竹中违法添加乌洛托品的方法。     

亲水作用高效液相色谱-串联质谱法测定薯片及饼干中丙烯酰胺的含量

目的 建立亲水作用高效液相色谱-串联质谱法测定薯片及饼干中丙烯酰胺含量的分析方法。方法 薯片及饼干经超纯水提取, 正己烷除脂, Cleanert? ACA固相萃取柱净化, BEH Amide色谱柱(2.1 mm×100 mm, 1.7 μm)分离, 并以0.1%(V:V)甲酸水-乙腈溶液=2:8(V:V)为流动相, 电喷雾正离子模式电离, 多反应监测模式检测, 内标法定量。结果 丙烯酰胺在5~2000 μg/L范围内线性关系良好, 相关系数大于0.999。方法的检出限(S/N＞3)和定量限(S/N＞10)分别为3 μg/kg和10 μg/kg。在不同基质中, 丙烯酰胺在20、200、1000 μg/kg的添加水平下平均加标回收率为91.5%~98.2%, 相对标准偏差为2.71%~4.82%。结论 此方法具有准确度好、灵敏度高等特点, 适用于薯片及饼干中丙烯酰胺的测定。     

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-串联质谱法测定肉鱼禽产品中的防腐剂月桂酰精氨酸乙酯盐酸盐

目的建立液相色谱串联质谱法测定肉鱼禽产品中的防腐剂月桂酰精氨酸乙酯盐酸盐(ethyl lauroyl arginine hydrochloride,LAE)的分析方法。方法通过超声波溶剂提取法提取样品中的LAE,通过色谱柱筛选确定Waters ACQUITY UPLC~BEH C_(18)(2.1 mm×100 mm,1.7μm)色谱柱,流动相为0.1%甲酸水溶液和乙腈,梯度洗脱,然后经质谱法检测,以外标法定量。结果最佳提取条件为:提取溶剂为水:乙腈=1:9(V:V),提取时间为5 min,提取次数为3次。LAE的线性范围为0~20μg/L,线性相关系数为0.9990。方法的检出限为0.3μg/kg,方法的定量限为1.0μg/kg;通过加标回收率实验,确定方法的加标回收率范围为82.5%~105.0%,符合GB27404-2008标准规定。结论本方法简单、便捷,适用于肉鱼禽产品中LAE含量的测定。     

凝胶渗透色谱-高效液相色谱法测定植物油中苯并芘

建立了用凝胶渗透色谱-高效液相色谱法测定植物油中苯并芘的方法。该方法以乙酸乙酯-环己烷(1:1,v/v)提取样品,凝胶渗透色谱净化,以ZORBAXSB-C18柱(4.6mm×250mm,5μm)分离,流动相为甲醇和水(90+10),流速1.0mL/min,激发波长365nm,发射波长412nm,柱温25℃,进样量25μL。该方法的检出限0.4μg/kg,线性范围0.1~10.0μg/L,加标回收率98.7%~109.2%,相对标准偏差为3.81%~8.76%。     

液相色谱-串联质谱法测定纺织品中全氟2-甲基-3-氧杂己酸

建立了测定纺织品中全氟2-甲基-3-氧杂己酸的液相色谱-串联质谱方法。样品经甲醇超声萃取,再经C₁₈(2.1 mm×100 mm,1.7 μm)色谱柱分离,以乙腈和10 mmol/L的乙酸铵水溶液为流动相梯度洗脱,经液相色谱-串联质谱测定,电喷雾离子源,负离子模式检测,外标法定量。结果表明：全氟2-甲基-3-氧杂己酸在质量浓度为0.1～5.0 μg/mL范围内具有优良的线性关系,线性相关系数大于0.995,定量检测下限为1.0 mg/kg,加标回收率在87.4%～107.0%,相对标准偏差(RSD)均小于7.5%。该方法操作简单、灵敏度高、能够满足纺织品中痕量残留物的检测要求。     

固相萃取-超高效液相色谱-串联质谱法测定啤酒中4-甲基咪唑的含量

目的建立啤酒中4-甲基咪唑的固相萃取-超高效液相色谱-串联质谱检测方法。方法样品经水提取,Agala PCX固相萃取柱净化,经色谱柱Waters ACQUITY BEH C_(18)柱(100 mm×2.1 mm,1.7μm)分离,超高效液相色谱-串联质谱多反应监测(MRM)模式测定,内标法定量。结果方法的线性范围为1.0~200μg/L,标准曲线线性相关系数为0.999 3,检出限为6μg/kg。高、中、低3个浓度水平的加标回收率为88.2%~89.6%,相对标准偏差小于5%。结论本方法灵敏、快速、准确,可用于啤酒中4-甲基咪唑的测定。     

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.