液相色谱-串联质谱测定乳制品中乳酸链球菌素

建立液相色谱-串联质谱法用于测定乳酸链球菌素的含量。PLRPS-S为色谱柱。样品经提取净化后,用超高效液相色谱分离后采用电喷雾串联质谱进行定性和定量检测。线性范围为0～1 000μg/L,线性相关系数r大于0.99,方法检出限为0.2 mg/kg,在加标浓度为0.2～5.0 mg/kg条件下的回收率为89.01%～104.52%,精密度为1.99%～8.77%。方法简单、灵敏、准确、精密,满足检测需求。     

高效液相色谱法分离测定湿巾中的荧光增白剂

建立高效液相色谱-二极管阵列检测法分离测定湿巾中三种荧光增白剂FWA 220、FWA 113和FWA71等物质的方法。采用Eclipse XDB-C18(4.6 mm×250 mm,5μm)色谱柱,流动相为乙腈-5 mol/L醋酸铵溶液进行梯度洗脱,检测波长为350 nm。实验结果表明,三种荧光增白剂在0.01~400.00 mg/L范围内具有良好的线性关系(相关系数均大于0.999 5),检出限和定量限分别在0.01~0.10 mg/L和0.5~5.0 mg/kg范围内。添加水平在10~800 mg/kg时,回收率范围为91.4%~102.2%,相对标准偏差(n=6)为1.6%~5.1%。该方法精密度高,重现性好,结果准确可靠,为荧光增白剂FWA220、FWA 113和FWA 71的质量评价提供了有效方法。     

液相色谱-串联质谱法同时测定纺织品中8种荧光增白剂

建立同时测定纺织品中C.I.85、C.I.28、C.I.134、C.I.162、C.I.135、C.I.185、C.I.367、C.I.184荧光增白剂含量的液相色谱-串联质谱检测方法。试样经乙腈-水-三乙胺（体积比：89/10/1）在50℃下超声萃取,以乙腈-甲醇-10 mmol/L乙酸铵水溶液（体积比：63/27/10）为流动相,电喷雾离子源正负离子选择反应监测模式测定。结果表明：8种荧光增白剂在一定浓度范围内线性关系良好,相关系数均大于0.99,检出限：0.01 mg/kg～0.32 mg/kg,方法回收率：88.32%～97.85%,精密度（n=6）:0.72%～5.33%。该方法分析时间短、分离能力强,适用于纺织品中荧光增白剂的快速检测。     

超高效液相色谱-串联质谱法检测食用菌中 荧光增白剂

目的 建立新鲜食用菌中荧光增白剂85(VBL)、荧光增白剂71(CXT)和荧光增白剂113(BA)的超高效液相色谱-串联质谱法(UPLC-MS/MS)定量检测方法。方法 采用60 %甲醇-水溶液,75°C水浴振荡提取试样中的荧光增白剂,经弱阴离子交换固相萃取柱净化,采用UPLC-MS/MS在负离子模式下检测,内标法定量。结果 该方法在0~0.500 mg/L范围内有良好的线性关系,相关系数r2＞0.990,在空白新鲜食用菌基质中,不同添加水平下方法的平均回收率范围为80.0%~101%,相对标准偏差为3.4 %-11.9%;测定低限为0.100 mg/kg。结论 此方法灵敏度高、准确、重现性好,适用于新鲜食用菌中荧光增白剂85、荧光增白剂71和荧光增白剂113的检测。     

搅拌棒萃取-液质联用法检测大蒜中啶虫脒

建立搅拌棒吸附萃取结合液相色谱-串联质谱法检测大蒜中啶虫脒残留。样品经搅拌棒萃取,解吸液解吸后,上机检测。采用Hypersil GOLD-1.9μm,50 mm×2.1 mm(i.d)色谱柱分离,在选择反应监测模式下检测,外标法定量。啶虫脒在浓度0.005 mg/L~0.2 mg/L范围内线性关系良好,相关系数r=0.999 8,方法检测限为0.005 mg/kg。在不同添加水平下,其平均回收率为82.3%~92.2%,变异系数为7.73%~9.01%。该方法简便、快速,适用于大蒜中啶虫脒残留的批量检测。     

水产品及螺旋藻片中微囊藻毒素检测方法研究

建立了超高效液相色谱-串联质谱法检测水产品及螺旋藻片中微囊藻毒素的高灵敏度色质联用快速检测方法。样品经溶剂超声提取、固相萃取净化,氮气吹至近干并定容后,通过超高效液相色谱-串联四极杆质谱仪检测。分离柱为Waters Acquity BEH C18柱(1.7μm,2.1 mm×100 mm);流动相为0.3%甲酸水溶液-乙腈;流速0.4 mL/min。4种不同基质样品中有害毒素微囊藻毒素MCYST-RR和MCYST-LR的检测限分别为0.7μg/kg和0.3μg/kg。4种不同基质样品中微囊藻毒素的回收率为80.0%～103.6%,相对标准偏差(RSD)为2.2%～14.6%(n=5),在0.01μg/mL～10μg/mL浓度范围内呈良好的线性关系,线性回归系数r2均大于0.999。     

搅拌棒萃取LC-MS/MS法检测大蒜中苯霜灵、扑灭津、哒螨灵及吡螨胺残留

建立了搅拌棒萃取(SBSE)结合液相色谱串联质谱法检测大蒜中苯霜灵、扑灭津、哒螨灵、吡螨胺4种农药残留。样品经搅拌棒萃取,解析液解析后,上机检测,采用Hypersil GOLD-1.9μm,50mm×2.1mm(i.d)色谱柱分离,在选择反应监测模式下检测,外标法定量。结果表明:四种农药在0.005-0.2mg/L浓度范围内线性关系良好,相关系数R2=0.9907-0.9985,方法检测限为0.005mg/kg。在不同添加水平下,其平均回收率为85.8-96.1%,变异系数为6.8-10.9%。     

搅拌棒萃取-LC-MS/MS法检测大蒜中苯霜灵、扑灭津、哒螨灵及吡螨胺残留

建立了搅拌棒萃取(SBSE)结合液相色谱串联质谱法检测大蒜中苯霜灵、扑灭津、哒螨灵、吡螨胺4种农药残留。样品经搅拌棒萃取,解析液解析后,上机检测,采用Hypersil GOLD-1.9μm,50 mm×2.1mm(i.d)色谱柱分离,在选择反应监测模式下检测,外标法定量。结果表明:四种农药在0.005-0.2mg/L浓度范围内线性关系良好,相关系数R2=0.9907-0.9985,方法检测限为0.005mg/kg。在不同添加水平下,其平均回收率为85.8-96.1%,变异系数为6.8-10.9%。     

棉纺织品中几种常用荧光增白剂的检测

研究高效液相色谱法测定纺织品中11种荧光增白剂残留量的检测效果。将样品在50℃温度下经70%二甲基甲酰胺水溶液超声提取40 min,提取液以Inertsil Ph-3色谱柱(4.6 mm×250 mm,5μm)作为固定相,甲醇、乙腈和水作为流动相进行梯度洗脱,有效分离了11种目标物质。试验结果表明:11种荧光增白剂检出限在0.2 mg/kg~14 mg/kg之间,定量低限在1.0 mg/kg~70 mg/kg之间,在0.01μg/m L~70μg/m L范围内峰强度与质量浓度的线性关系良好(r0.999 0),方法的平均回收率在83.23%~101.51%之间。认为:该方法简单快速,稳定准确,灵敏度高,可适合于大批量检测纺织品样品。     

超高液相色谱串联质谱法检测土豆及土豆制品中α-茄碱

目的建立超高效液相色谱串联质谱法检测土豆及其制品中α-茄碱的分析方法。方法通过优化提取液,土豆样品经1%甲酸-甲醇(1:1,V:V)超声提取,采用BEH C_(18)色谱柱(2.1 mm×50 mm,1.7μm)分离,梯度洗脱,采用超高效液相色谱串联质谱法,在多反应监测模式进行定性和定量分析,而土豆淀粉用MCX固相萃取柱进行净化,液相色谱串联质谱法测定。结果土豆样品中回收率为75%~115%,相对标准偏差为5.0%~8.6%,土豆淀粉的回收率范围为67%~100%,相对标准偏差为3.4%~11.3%,方法的检出限和定量限分别为0.5 mg/kg和1.0 mg/kg。结论该方法适合于土豆及其制品中α-茄碱的分析。     

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.