气相色谱法同时测定大豆中13种苯氧羧酸类除草剂的残留量

为检测大豆中的苯氧羧酸类除草剂残留,建立了大豆中13种苯氧羧酸类除草剂(对氯苯氧乙酸、对氯苯氧丙酸、苯氧丁酸、麦草畏、2甲4氯苯氧乙酸、2甲4氯苯氧丙酸、2甲4氯苯氧丁酸、2,4-滴、3,4-滴、2,4,5-涕、2,4,5-涕丙酸、2,4-滴丙酸、2,4-滴丁酸)多残留量的气相色谱检测方法。样品经过正己烷预除脂后用乙腈和50mmol/L盐酸混和液(体积比7 3)提取,提取液经过与乙腈饱和的正己烷液液分配除脂,阴离子交换柱净化后用五氟溴苄衍生化。衍生产物经硅胶柱净化后,采用气相色谱(GC)-电子捕获检测器(ECD)检测,外标法定量。13种苯氧羧酸类除草剂在质量浓度0.005～0.1mg/kg之间,与峰面积呈线性关系,相关系数为0.9954～0.9993;0.01和0.1mg/kg2个水平的加标回收率均在70%以上,相对标准偏差小于20%,方法的检测限(S/N≥3)满足主要贸易国最大残留限量要求。     

超高效液相色谱-串联质谱法测定食用猪油中氯酚类物质

目的应用超高效液相色谱-串联质谱技术,建立同时测定食用猪油中2,4,5-三氯苯酚、2,4,5-三氯苯氧乙酸和五氯酚3种物质的方法。方法样品用80%乙腈提取,固相萃取(SPE)和正己烷净化萃取后,以Atlantis?T3(2.1 mm×150 mm,3μm)为分析柱,乙腈-5.0 mmol/L乙酸铵溶液为流动相,以电喷雾离子源在负离子多反应监测模式下进行测定,基质匹配外标法定量。结果 2,4,5-三氯苯酚、2,4,5-三氯苯氧乙酸和五氯酚在2.0～100.0μg/L范围内线性关系良好,相关系数(r)均大于0.999,方法检出限分别为0.09、1.59、0.90μg/kg,定量限分别为0.29、5.28、3.00μg/kg,回收率为71.9%～109.5%,相对标准偏差为0.2%～9.2%(n=6)。结论该方法简便、准确、灵敏度高,适用于食用猪油中2,4,5-三氯苯酚、2,4,5-三氯苯氧乙酸、五氯酚3种物质的高通量检测。     

QuEChERS-液质联用法测定菜籽油中7种 芳氧苯氧丙酸酯类除草剂残留备工艺研究

建立了分散固相萃取(QuEChERS)净化方法结合液质联用(HPLC-MS/MS)检测技术同时测定菜籽油中7种芳氧苯氧丙酸酯类除草剂的方法。结果表明：最优检测条件为采用90%乙腈水溶液提取2次, Supel QuE Z-Sep+分散固相萃取净化,色谱柱为sunshell C18柱（2.6 μm×2.1 mm×100 mm）,以乙腈和0.025%乙酸水溶液进行梯度洗脱,MRM模式。在最优检测条件下,除精恶唑禾草灵外6种除草剂线性范围0～100（50）μg/L,相关系数R大于0.999 5,定量限在0.25～2.5 μg/kg之间,回收率在78.3%～95.1%之间,相对标准偏差在0.9%～6.5%之间。方法具有基质效应低、处理简单、准确快速、重复性好的优点,适用于实验室高通量快速检测菜籽油样品。     

正相色谱法同时测定黄豆酱中的两类防腐剂

建立一种用正相高效液相色谱法同时测定黄豆酱中苯甲酸、山梨酸和对羟基苯甲酸酯类防腐剂的新方法.Allsphere Cyano(CN)柱(250 mm×4.6 mm i.d.,5 μm)为分离柱,二氯甲烷-乙腈(92:8)为流动相(乙酸调pH 5.5),流速:1.0 mL/min,检测波长240 nm.在0.01～50μg/mL范围内5种组分均线性良好.方法检出限0.05～0.1 μg/g.回收率在80.61%～98.36%之间.     

气相色谱-质谱联用测定白酒中的氨基甲酸甲酯和氨基甲酸乙酯

建立一种测定白酒中的氨基甲酸甲酯和氨基甲酸乙酯的气相色谱-质谱联用(gas chromatography-mass spectrometry,GC-MS)方法。GC-MS条件为：色谱柱HP-55%苯甲基硅氧烷(30.0m×0.25mm,0.25μm),进样1μL(分流比50:1),柱温170℃,质谱离子源温度230℃,四极杆温度150℃,全扫描方式的质量扫描范围m/z 30～500,溶剂延迟3min。样品采用氨基固相小柱萃取净化、氮吹浓缩定容。结果表明：氨基甲酸甲酯和氨基甲酸乙酯在2～30μg/mL范围内线性关系良好,相关系数为0.9923和0.9811,平均回收率为76.10%和75.43%,RSD为4.48%和4.00%。该方法可应用于白酒检测。     

固相萃取——高效液相色谱法同时检测红小豆中咪唑啉酮类除草剂

为建立一种同时测定红小豆中6种咪唑啉酮类除草剂残留的反相高效液相色谱分析方法, 将样品粉碎过筛后,用二氯甲烷超声提取,经OASIS MCX固相萃取柱净化,采用Agilent TC-C18(250mmx4.6mm,i.d 5μm)色谱柱,磷酸水溶液(pH 3.5)-乙腈为流动相梯度分离,流速1 mL/min,紫外检测波长252 nm,以外标法定量.结果表明:咪唑啉酮类除草剂在质量浓度0.01～1.00 μg/mL(灭草喹0.004～0.5 μg/mL)范围内, 标准曲线的线性相关系数范围0.9998～0.9999;方法检出限(LOD)0.0016～0.004 mg/kg;红小豆中的平均加标回收率72.2%～98.8%,相对标准偏差(RSD)1.02%～4.86%.该分析方法操作简便,灵敏度高,重现性好,适用于红小豆中咪唑啉酮类农药的多残留检测.     

基质分散固相萃取-高效液相色谱-可变波长检测法测定新鲜牛奶中8种抗生素

摘要：目的 建立基于基质分散固相萃取-高效液相色谱的新鲜牛奶中氯霉素、呋喃唑酮、甲硝唑、磺胺嘧啶、磺胺吡啶、磺胺-5-甲氧嘧啶、磺胺甲基异恶唑、磺胺二甲氧嘧啶8种抗生素的分析方法。方法 采用0.5%乙酸乙腈对新鲜牛奶中的8种抗生素进行提取,提取液用C18粉末和乙二胺-N-丙基甲硅烷(primary secondary amine, PSA)粉末基质分散固相萃取,以乙酸酸化的乙腈溶液(pH=3.0)和0.05 mol/L磷酸二氢钾溶液(pH=3.0)为流动相,Eclipse XDB-C18(4.6 mm×150 mm, 5 μm)色谱柱,梯度淋洗分离,多波长检测定量。结果 8种抗生素在1.0~100.0 μg/kg浓度范围内线性关系良好,相关系数为0.99904~1.00000;对新鲜牛奶进行3个水平(5、20、50 μg/kg)的加标回收实验,其回收率为84%~101%,相对标准偏差为2.4%~10.7%;检出限为0.18~0.41 μg/kg,定量限为0.63~1.23 μg/kg。结论 本方法适用于新鲜牛奶或液态奶中抗生素的检测,其前处理方法简便、回收率高、灵敏度高,能够满足实验要求。     

UPLC-MS/MS测定植烟土壤中有机氯除草剂的残留量

建立了快速测定植烟土壤中的3种有机氯除草剂(麦草畏、2,4-D和2,4,5-T)的超高效液相色谱-串联质谱(UPLC-MS/MS)方法.该方法以麦草畏-d3、2,4-D-d3和2,4,5-T-d2为内标,土壤样品经乙腈提取、N-丙基乙二胺(PSA)净化和0.45 μm有机相微孔滤膜过滤后进行UPLC-MS/MS测定,分析时间仅需4 min.麦草畏、2,4-D和2,4,5-T的工作曲线在1～100 ng/mL之间线性关系良好(R2＞0.99),检出限(LOD,以S/N=3计)分别为0.025,0.002和0.003 ng/mL;在20,100和400 ng/g加标水平下,其平均回收率在84.8％～104.1％之间,RSD为2.1％～10.4％.该方法准确可靠、灵敏度高,适用于植烟土壤中3种有机氯除草剂残留的快速定量分析.     

GC-FID法同时测定腌制鱼干中9种N-亚硝胺类化合物

在气相色谱-氢火焰检测器的基础上建立了同时测定腌制鱼干中9种N-亚硝胺类化合物的方法。采用碱液加热处理结合二氯甲烷萃取的方法提取腌制鱼干的N-亚硝胺,经棷壳活性炭净化,C₁₈固相萃取(SPE,Solid Phase extraction)小柱富集,样液用DB-WAXETR极性柱(30 m×0.25 mm,0.25 μm)进行色谱分离,柱温采用程序升温。结果显示:该方法下的9种N-亚硝胺类化合物在0.05~5 μg/mL浓度范围内线性良好(R2＞0. 999);检出限和定量限范围分别为0.05~0.29 μg/mL和0.18~0.95 μg/mL;回收率和RSD分别为76.8%~129.5%和2.29%~15.5%。对市售的50种腌制鱼干进行检测,N-亚硝基二乙胺(NDEA,N-nitrosodiethylamine)、N-亚硝基哌啶(NDIP,N-Nitrosopiperidine)N-亚硝基吡咯烷(NPYR,N-Nitrosopyrrolidine)检出率分别达到20%、20%、24%,只有一种样品的N-亚硝基二甲胺(NDMA,N-nitrosodimethylamine)超过国标限量规定(4 μg/kg)。     

双水相萃取-高效液相色谱法分析红小豆中酰胺除草剂

建立以硫酸铵-乙醇为基础的双水相萃取法,在红小豆中萃取分离富集乙草胺、丁草胺、敌稗、异丙甲草胺4 种酰胺类除草剂的方法。采用高效液相色谱法对4 种除草剂进行分析测定。在双水相萃取过程中,上相富醇溶液的极性更接近于同一有机溶剂中除草剂的极性。下相盐溶液能有效沉淀蛋白质和脂肪。考察前处理条件,最终选择硫酸铵-乙醇体系双水相体系类型、25%乙醇、28%硫酸铵、35 ℃、1 min超声萃取时间为最佳前处理条件。由于避免了有毒有机溶剂,本方法是一种环境友好的方法。乙草胺、丁草胺、敌稗、异丙甲草胺的检测限分别为3.5、7.1、4.6、5.8 μg/kg。在加标量为10 μg/kg和100 μg/kg水平下,4 种酰胺除草剂的平均回收率范围为86.1%～95.9%,相对标准偏差≤4.5%。     

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.     

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.     

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.     

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.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.     

Analysis on Economic Indicators from 62 Enterprises in Printing Machinery Industry in Q1 2014

Operation of printing machine industry was still unsatisfactory in the first quarter of 2014.Analysis on operation of printing machine industry.a.Market demand was not strong;sales of product undulated and declined.According to the statistics,the total industrial output value fell by 19.28% in the first quarter of 2014 than the average quarter value in 2013; industrial added value decreased by 4.16%; sales revenue dropped by 22.83%. h. Business operation of enterprises was in poor condition. c. R＆D of new products is an important transformation guarantee for enterprises. d. To take self explore new ways upgrading advantages,and explore new ways.