白酒中氨基甲酸甲酯农药残留量的GC/MS测定方法研究

建立了气相色谱-质谱法测定白酒中氨基甲酸甲酯农药残留的分析方法.探讨了白酒样品前处理条件的优化与选择,酒样用Florisil萃取柱净化和环己烷 乙酸乙酯(1 1)洗脱后.采用选择离子监测模式下的GC-EI/MS分析.当酒样的加标浓度为20靏/L、50靏/L和100 靏/L时,加标回收率为78.7%～86.2%,相对标准偏差小于8.2%.本方法中氨基甲酸甲酯的检测限为12.5靏/L,线性范围为0.02～2.0靏/mL,样品中氨基甲酸甲酯的最小检出浓度为0.25 靏/L.在检测的6种白酒中,有2种检出氨基甲酸甲酯,含量分别为1.8靏/L、28.9靏/L,其余酒样未栓出.此分析方法可用于白酒样品中痕量农药残留的分析.     

白苏不同部位中齐墩果酸和乌索酸的测定比较

建立反相高效液相.光电二极管阵列检测器法(RP-HPLC-PAD)测定白苏叶、茎、根中的齐墩果酸和乌索酸,并对2种三萜酸成分进行定性定量分析.采用Kromasil C18色谱柱(4.6mm×250mm,50靘),以甲醇-0.2%磷酸溶液(90:10,v/v)为流动相进行等度洗脱,流速0.8mL/min,检测波长210nm,柱温25℃.齐墩果酸在0.1248靏-2.49%靏、乌索酸在0.2184靏-4.36靏范围内具有良好的线性关系,平均回收率分别为98.5%和101.3%.选定的色谱条件可精确的检测白苏不同部位中齐墩果酸和乌索酸的含量.     

液相色谱-电喷雾质谱法测定白酒中5种有机磷农药残留

建立了固相萃取-高效液相色谱-电喷雾质谱(HPLC-S)测定白酒中乐果、敌敌畏、甲基对硫磷、马拉硫磷、对硫磷农药残留的检测方法.白酒样品用C18固相萃取柱富集净化、二氯甲烷洗脱、氮吹浓缩;采用C18反相色谱柱,以含有0.1%乙酸的水/甲醇(35∶65,v/v)为流动相;电喷雾正离子模式,选择有机磷农药的准分子离子为定性离子进行MS测定.结果表明,5种有机磷农药的平均加标回收率为71.0%～87.8%,相对标准偏差为2.7%～8.5%;方法的最小检出限为0.05～0.16靏/L.该法有很高的选择性、灵敏度和准确度,满足白酒中痕量有机磷农药的高灵敏分析.     

氢化物发生-原子荧光光谱法同时测定食品中的镉和锡

为提高食品中镉和锡的检测水平,建立了氢化物发生-原子荧光光谱法同时测定食品中的镉和锡的方法.在最佳实验条件下的检出限:镉0.002 9 ng/ml、锡0.19 ng/ml;线性范围:镉0～2ng/ml,相关系数0.999 8,锡0～100 ng/ml,相关系数0.999 9;在0.5 ng/ml时,镉测定的相对标准偏差为1.5%(RSD),2.5 ng/ml时锡的相对标准偏差为3.1%(RSD);试样加标回收率:镉93.0%～100.5%,锡91.3%～99.2%.该方法具有操作简便、快速、检出限低、灵敏度高、结果准确等优点,适合于各种食品镉、锡的联合测定.     

石墨炉原子吸收分光光度法测定黄豆及腐竹中的硼

目的 建立测定黄豆及腐竹中硼含童的石墨炉原子吸收分光光度法.方法 样品经过HNO_3 + H_2O_2微波消解或加入饱和的Ca(OH)_2助灰化剂干灰化后,选择硝酸钙(10 m/ml)-硝酸铵(20 mg/ml)-柠稼酸(20mg/ml)的混合液作为化学改进剂,采用热解涂层石墨炉原子吸收分光光度法进行测定.结果 硼含量在0～1μg/ml的线性范围内呈线性关系,相关系数r=0.9996,检出限0.017 09μg/ml;方法的精密度(RSD,n=6)为3.56% ～6.45%,回收率为87.20% ～93.70% o结论建立的方法操作简便易行,重现性、灵敏度和准确性能满足分析要求,适用于黄豆及腐竹中硼含量的测定.     

抗坏血酸的共振光散射法测定

研究了在醋酸缓冲介质中,抗坏血酸(VC)还原Cu2 定量所形成CuSCN的共振散射光谱.确定了散射光强度与溶液中VC浓度的关系.提出了共振散射法测定VC的新方法.方法的检出限为0.25ng/ml,线性范围为0.25～1.25 μg/ml.方法用于VC片、饮料中抗坏血酸的测定,结果令人满意.     

红心鸭蛋蛋黄中类胡萝卜素油提效果初试

本文研究了通过普通的食用油来提取天然红心鸭蛋蛋黄里的类胡萝卜素,结果表明在料液比13,提取温度为80,每次时间为60min,提取三次的条件下浸提的效果较好,其油中类胡萝卜素的含量为58.2靏/g,得率为53.2%。     

双酚A残留的检测方法研究

建立了用液相色谱.串联质谱技术测定双酚A残留的方法.质谱采用电喷雾电离源(ESI).负离子采集模式,选择反应监测技术(SRM),定量离子对为m/z 227>132、114;甲醇.水(3:7)为流动相,流速500μl/min.方法的检出限为1.8ng/ml,线性范围20.0～2000.0ng/ml,回收率91%.并实验比较了液相色谱紫外检测器与串联质谱检测的灵敏度和选择性,结果表明LC-MS2方法灵敏、准确、快速.     

枯草芽孢杆菌B.subtilis CNMC-0014深层摇瓶发酵生产中性蛋白酶 -培养基组分及培养条件对酶生物合成的影响

应用统计学方法优化了B.sustilis CNMC-0014中性蛋白酶产生的培养基组分.单因素试验研究发现,在测试的6种碳源中,以甘油和玉米粉对产酶影响显著,酶活力分别达到了3955.16±2.15U/ml和3939.15± 1.87U/ml.氮源试验中发现,大豆粉对产酶影响最为显著,酶活力达到4318.12±5.66U/ml.通过极差分析与正交分析优化了培养基配比,优化方案为:2%玉米粉,1%甘油,3%玉米粉和3%麸皮.方差分析结果发现,甘油和玉米粉对产酶影响显著(p＜0.05),大豆粉对产酶极显著(p＜0.01), 麸皮对产酶影响不显著(p＞0.05).同时,还 研究了金属离子、溶氧、起始pH值、菌龄以及接种量对产酶的影响,研究结果表明,Ca 2 、Mg2 、Na 、Zn 、Mn2 可以在不同程度对产酶有激活作用,特别是Ca 2 ,酶活力达到了4552.97U/ml,而Fe3 、Fe2 、K 、Ag 对产酶有强烈的抑制作用,特别是Ag (酶活力仅为987.46 U/ml),最适摇瓶装量为50ml/300ml,最佳起始pH值为7.5,最佳菌龄与接种量分别为24h和3%.     

杏鲍菇深层发酵培养基的优化

对影响杏鲍菇生长的4个主要营养因子进行试验研究,得出液体培养杏鲍菇最佳碳源为可溶性淀粉,最佳氮源为黄豆粉,最佳无机盐KCl,最佳维生素为复合VB;对液体培养杏鲍菇的最佳碳源、氮源、无机盐和维生素的不同配比进行正交试验,得出液体培养杏鲍菇的最佳培养基配方为:5%可溶性淀粉、3%黄豆粉、0.15%KC1、75靏/mL的复合VB.用优选培养条件培养杏鲍菇菌丝,每100mL培养液平均可产干菌丝3.163g.     

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.     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the