SPE-HPLC法测定大米中甲萘威残留的研究

建立了大米中甲萘威农药残留量的固相萃取-高效液相色谱(SPE-HPLC)分析方法。以乙腈为提取剂,振荡提取,采用C_(18)固相萃取柱净化,经C_(18)柱(3.9 mm×300 mm,10μm)分离,乙腈-水(55︰45,V/V)为流动相,柱温40℃,流速1.0 m L/min进行分离,紫外检测器280 nm下进行检测。甲萘威的质量浓度在0.05~2.00μg/mL范围内线性良好,相关系数为0.999 9。在0.50,1.25和2.50 mg/kg 3个添加水平下,甲萘威的加标回收率为92.41%~110.18%,相对标准偏差在2.91%~4.35%(n=6),检出限为0.006 mg/kg。该方法具有样品前处理操作简单、灵敏度高、试剂用量少、重现性好等优点,适用于大米中甲萘威的定性定量分析。     

高效液相色谱法测定牛奶中硫氰酸钠含量

目的采用高效液相色谱法检测牛奶中硫氰酸钠含量。方法样品用5 m L乙腈沉淀蛋白质,上清液过C_(18)柱净化。以磷酸缓冲溶液(pH=7.0):乙腈(95:5,V:V)作为流动相,C18色谱柱(250 mm×4.6 mm,5μm)分析,柱温30℃±2℃,流速1.0 m L/min,以紫外检测器分析样品。结果该方法对牛奶中硫氰酸钠有较高的提取率,质量浓度范围在5~100 mg/L内线性较好(r~2=0.9995),检测限1.0 mg/kg,回收率90%。结论该方法具有预处理简单、灵敏度高的优点,满足对牛奶中硫氰酸钠含量的检测要求。     

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。     

HPLC法测定乳饮料中纽甜含量的研究

建立快速、准确测定乳饮料中纽甜含量的高效液相色谱检测方法。样品以20%乙腈水溶液为提取液,硫酸锌和亚铁氰化钾为沉淀剂进行前处理,采用ZORBAX SB-C18(250 mm×4.6 mm,5μm)色谱柱,200 nm检测波长,磷酸氢二铵(0.020 mol/L,pH 3.5~4):乙腈=(70∶30)为流动相进行等度洗脱分离。纽甜在0.2μg/m L~50.0μg/m L范围内线性良好,在0.8 mg/kg~5.0 mg/kg加标范围内,回收率为90.1%~96.1%,RSD值为1.7%~2.1%,最低定量限为0.30 mg/kg。     

薏米茯苓黄酒中功能性成分的测定

以薏米、茯苓为主要原料,进行液态发酵薏米茯苓黄酒的实验,采用高效液相色谱方法对薏米茯苓黄酒中功能性成分进行定性定量分析,色谱条件为:酚类物质,Phenomenex Synergi Hydro-RP C_(18)色谱柱(250×4.6 mm,4μm)作为分离柱,乙腈和1%的乙酸水作为流动相进行梯度洗脱,流速1 mL/min,紫外检测波长280 nm;薏苡素,Sino Chrom ODS-BP C_(18)色谱柱(250×4.6 mm,5μm)作为分离柱,乙腈和水作为流动相进行梯度洗脱,流速1 mL/min,紫外检测波长235 nm;茯苓酸,Sino Chrom ODS-BP C_(18)色谱柱(250×4.6 mm,5μm)作为分离柱,乙腈和磷酸水作为流动相进行梯度洗脱,流速0.9 mL/min,紫外检测波长203 nm。结果表明,方法的检出限为0.202~0.337 mg/L,回收率均在87.10%~100.79%,相对标准偏差为0.47%~2.63%之间。     

加压毛细管电色谱测定乳及乳制品中三聚氰胺

研究建立利用加压毛细管电色谱(p CEC)测定乳及乳制品中三聚氰胺的分析方法。样品采用2%三氯乙酸水溶液超声提取,阳离子固相萃取柱(MCX)净化,提取液经C18反相毛细管电色谱柱分离,流动相乙腈-10 mmol/L辛烷磺酸钠溶液(p H 3.0)=15+85,泵流速0.05 m L/min,分离电压-2 k V,紫外检测器240 nm检测。该方法在1.0 mg/kg~100 mg/kg质量浓度范围内线性关系良好(R2=0.999),在牛奶和酸奶中的定量限为2.5 mg/kg,在奶粉中的定量限为10 mg/kg,加标回收率为78.9%~93.5%,相对标准偏差小于5%。     

高效液相色谱法同时测定柠檬中柠檬苦素和诺米林含量

目的建立高效液相色谱法同时测定柠檬中柠檬苦素和诺米林含量。方法样品经乙酸乙酯超声波辅助提取,高速离心机分离得到提取液,提取液经无水硫酸钠脱水处理,旋转蒸収仪减压浓缩、定容后待测。使用Shiseido CAPCELL PAK MGⅡC_(18)色谱柱(250 mm×4.6 mm,5.0μm),以乙腈-0.10%磷酸水溶液(45:55,V:V)为流动相;流速:0.70 m L/min;进样量:10μL;检测波长:215 nm。结果柠檬苦素和诺米林在0.50~1000.0 mg/L质量浓度范围内呈良好线性兲系,线性相兲系数r≥0.9993,检出限为0.25、0.34 mg/L,定量限为0.70、0.95 mg/L。3个添加水平(100.0、200.0和500.0 mg/kg)下的加标回收率为82.60%~108.7%,相对标准偏差为3.56%~5.22%。结论该方法具有操作简单,重复性和稳定性好等优点,可准确测定柠檬汁和柠檬皮中诺米林和柠檬苦素的含量。     

高效液相色谱法测定马铃薯和土壤中的辛硫磷残留

目的建立高效液相色谱法测定马铃薯和土壤中辛硫磷残留的分析方法。方法样品经乙腈萃取,氨基固相萃取小柱净化,采用以色谱柱Agilent ZARBAX SB-C_(18) 柱(4.6 mm×250 mm,5μm)分离,甲醇/水(75:25,V:V)为流动相等度洗脱后紫外检测器检测,检测波长为280 nm。结果辛硫磷在0.05~10 mg/L浓度范围内线性关系良好(r~2=0.9990);最低检出限为0.02 mg/kg,辛硫磷在马铃薯块茎、植株和土壤中的添加水平为0.05~5.0 mg/kg时,添加回收率分别为92.3%~102.4%、98.5%~109.1%和89.7%~104.3%,相对标准偏差分别为1.0%~2.5%、1.4%~5.6%和1.4%~2.1%。结论该方法具有快速、准确、灵敏度高等特点,符合国家标准对食品中农药残留测定的要求。     

超高效液相色谱-串联质谱法测定茶叶中6种农药残留

目的建立超高效液相色谱-串联质谱法测定茶叶中吡虫啉、多菌灵、啶虫脒、水胺硫磷、三唑磷和甲基异柳磷6种农药残留的方法。方法样品经乙腈提取,NH_2固相萃取小柱富集、净化,以二氯甲烷-甲醇(9:1,V:V)为洗脱溶液;样品经浓缩定容后,采用Thermo C_(18)(2.1 mm×50 mm,1.7μm)色谱柱分离,流速为0.3 mL/min,以水-甲醇-乙腈为流动相进行梯度洗脱,采用超高效液相色谱-串联质谱法多反应监测模式进行测定,采用基质标准溶液外标法定量。结果 6种农药在0.005~0.25μg/mL浓度范围内呈良好的线性关系,相关系数为0.9973~0.9998。当添加水平为0.005、0.025、0.25 mg/kg时,6种农药在茶叶中的加标回收率为72.4%~106.6%,相对标准偏差为1.6%~10.0%。方法定量限为0.5~5μg/kg。结论该方法操作简单、快速,可适用于茶叶中吡虫啉、啶虫脒、多菌灵、水胺硫磷、三唑磷和甲基异柳磷6种农药残留的测定。     

气相色谱-串联质谱法测定韭菜中的氯氟氰菊酯残留

目的建立气相色谱-串联质谱法(gas chromatography-tandem mass spectrometry,GC-MS/MS)测定韭菜中氯氟氰菊酯残留量的分析方法。方法将韭菜样品的乙腈提取物经石墨化碳黑/氨基混合型固相萃取柱净化、乙腈-甲苯(3:1,V:V)洗脱以及浓缩定容后进行检测。目标化合物经SLB-5MS(30 m×0.25 mm,0.25μm)色谱柱分离后,通过三重串联四级杆多反应监测模式对其进行定性定量分析。结果在添加水平为0.05~0.50mg/L(n=5)时,氯氟氰菊酯的回收率在81.7%~99.1%之间,相对标准差(RSD)在2.5%~8.7%之间。该方法的线性范围为0.05~0.50 mg/L,相关系数r~20.990,检出限为0.001 mg/kg,定量限为0.01 mg/kg。结论该方法能满足韭菜中氯氟氰菊酯残留检测的要求。     

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.