超高效液相色谱-高分辨质谱法测定牛奶中新烟碱类农药残留

目的建立牛奶中7种新烟碱类农药残留的超高效液相色谱-高分辨质谱痕量检测方法。方法样品基于乙腈-水的冷冻诱导液液萃取(LLE)和分散固相萃取(DSPE)提取、富集和净化后,采用乙腈-水作为流动相,梯度洗脱,HSS T3色谱柱(2.1 mm×100 mm, 1.8μm)分离,高分辨质谱靶向单一离子监测模式测定,内标法定量。结果在一定的浓度范围内,7种新烟碱类农药呈良好的线性关系(R~20.999);方法检出限为3～7 ng/L,定量限为8～20 ng/L。牛奶中20、100、1 000 ng/L三种加标水平的平均回收率在89.4%～105.7%之间,日内精密度(RSD_r)在0.8%～6.4%之间,日间精密度(RSD_R)在11.0%以下。结论该方法基于冷冻诱导LLE和DSPE净化技术,实现提取、富集和净化的一步式样品前处理,简单快速、成本较低,方法灵敏度高、重现性好,可应用于牛奶中新烟碱类农药残留的痕量检测。     

高效液相色谱-四极杆-高分辨飞行时间质谱直接进样测定饮用水中8种微囊藻毒素

目的建立了高效液相色谱-四极杆-高分辨飞行时间质谱测定饮用水中8种微囊藻毒素的检测方法。方法水样经亲水聚四氟乙烯滤膜过滤后,采用Poroshell 120 EC-C_(18)色谱柱(2.1mm×100mm,2.7μm)分离,高效液相色谱-四极杆-高分辨飞行时间质谱检测,采用高分辨多反应监测扫描模式进行监测,外标法定量。结果 8种微囊毒素在0.1～50.0μg/L线范围内线性关系良好,相关系数大于0.998以上,方法的检出限在0.05～0.10μg/L。在1、5、10μg/L3个水平浓度添加时,其平均回收率在83.2%～105.4%,相对标准偏差为2.5%～11.8%。结论该方法简单、快速、灵敏度高、重复性好,适合于饮用水中微囊藻毒素的日常检测。     

液相色谱-串联三重四极杆质谱测定牛奶中的氯霉素残留量

建立牛奶中氯霉素残留的高效液相色谱-串联四极杆质谱联用测定方法。该方法经乙腈提取样品,以MGⅢ-C18柱(2.1×150 mm,1.8μm)分离,流动相为水溶液和乙腈(体积比为65∶35),电喷雾负离子MRM模式检测。该方法的检出限0.07μg/L,线性范围0.05μg/L~20.0μg/L,加标回收率98.5%～110.8%,相对标准偏差为3.57%。     

液质联用技术测定茶叶中多菌灵残留

建立茶叶中多菌灵残留的高效液相色谱-串联四极杆质谱联用测定方法。该方法中样品经0.2 mol/L盐酸甲醇溶液(1∶1,υ/υ)超声提取,MCX固相萃取柱净化,以ZORBAX Eclipse XDB-C18色谱柱(3.0 mm×50 mm,1.8μm)分离,流动相为0.1%甲酸水和乙腈(梯度洗脱),电喷雾正离子MRM模式检测。该方法的检出限为1.0μg/kg,线性范围0.5μg/L～3 000μg/L,加标回收率为85.0%～96.0%,相对标准偏差为3.71%。     

液相色谱-串联三重四极杆质谱测定饮料中双酚A残留

建立饮料中双酚A残留的高效液相色谱-串联四极杆质谱联用测定方法.方法为:用乙腈处理样品,以ZORBAX XDB-C18柱(2.1 mm×150 mm,5μm)分离,流动相为乙腈和水溶液(梯度洗脱),电喷雾负离子MRM模式检测.该方法的检出限5.0μg/L,方法定量下限10.0μg/L,线性范围5.0μg/L～100.0μg/L,加标回收率96.2%～102.5%,相对标准偏差为2.30%.     

盐辅助分散液液微萃取-气相色谱-串联质谱法检测葡萄酒中的氨基甲酸乙酯

目的建立了盐辅助分散液液微萃取(salt-assisted dispersive liquid-liquid microextraction,SADLLME),稳定同位素稀释,气相色谱-串联质谱法(gas chromatography-tandem mass spectrometry,GC-MS/MS)检测葡萄酒中氨基甲酸乙酯(ethyl carbamate,EC)的方法。方法取30 mL葡萄酒于50 mL离心管中,加入浓度为10μg/mL的EC-d5溶液100μL和硫酸钠3 g,震荡溶解,注射针快速打入700μL二氯甲烷,震荡1 min,离心,取下层有机相,经DB-INNWAX UI色谱柱(30 m×0.25 mm,0.25μm)分离,多重反应监测方式进行质谱检测。结果方法在验证浓度范围内(5～1500 ng/mL),线性良好,r~2=0.9988,检出限为0.73μg/L,定量限为2.18μg/L,回收率为91.5%～97.8%,相对标准偏差为2.55%～5.26%。对市场上3个品牌红葡萄酒进行检测,EC含量为6.82～15.3μg/L。结论该方法样品处理简便、快速,相对绿色,定性、定量可靠,能够满足葡萄酒中EC风险监测的需要。     

高效液相色谱-串联四极杆质谱联用测定饼干中丙烯酰胺残留量

建立饼干中丙烯酰胺残留的高效液相色谱-串联四极杆质谱联用测定方法.该方法经纯水提取样品,以ZORBAX SB-Aq柱(4.6×150mm,5μm)分离,流动相为0.1%甲酸水溶液和乙腈(体积比为97:3),电喷雾正离子MRM模式检测.该方法的检出限0.3μg/L,方法定量下限3.0μg/kg,线性范围0.3μg/L～100.0μg/L,加标回收率91.5%～99.5%,相对标准偏差为4.44%.     

液质联用法测定牛奶中氯霉素类药物残留

建立了牛奶中氯霉素、甲砜霉素和氟甲砜霉素多残留的高效液相色谱-串联四极杆质谱联用测定方法。样品经碱性乙腈超声提取,以MGⅢ-C18色谱柱(2.1×150 mm,5μm)分离,流动相为10 mmol/L乙酸铵水溶液和甲醇(梯度洗脱),流速0.25 m L/min。采用多反应监测负离子模式,可以同时对牛奶中的氯霉素、甲砜霉素和氟甲砜霉素进行定性和定量测定。方法的检出限为0.1μg/kg~0.3μg/kg。在0.3、3.0、10.0μg/kg 3个加标水平下,加标回收率为80.7%~93.6%,相对标准偏差为3.85%~9.35%。     

超高效液相色谱-串联质谱法测定牛奶中23种兽药

建立超高效液相色谱-串联质谱测定牛奶中23种兽药残留的检测方法。用乙腈(含2%甲酸)提取牛奶样品中的目标化合物,经oasis PriMe HLB小柱净化后,氮气吹扫,用5%甲醇水溶液溶解残余物后分析。以水(含0.1%甲酸)-甲醇(含0.1%甲酸)为流动相,选择HSS T3色谱柱(2.1 mm×100 mm, 1.8μm)分离目标化合物,采用电喷雾电离串联三重四级杆质谱在多反应监测(MrM)模式下进行测定,外标法定量。23种兽药化合物的检出限为0.005～3.026μg/kg,定量限为0.1～10μg/kg,加标回收率为70.98%～118.63%,相对标准偏差为0.14%～11.55%,该方法简单快捷、准确可靠,可用于牛奶中23种兽药的检测。     

UPLC-MS/MS法同时检测食品中3种主要牛奶过敏原

为准确定量食品中的牛奶过敏原，采用超高效液相色谱-串联质谱法同时检测3?种主要牛奶过敏原β-乳球蛋白、αs1-酪蛋白和αs2-酪蛋白，避免单一致敏蛋白在加工中的降解和灵敏度不高导致的假阴性。标准蛋白酶解液经纳升液相色谱-串联轨道阱高分辨质谱分析后，筛选得到8?条特征肽段。利用三重四极杆质谱多反应监测模式，选择面粉作为空白基质进行方法学验证。结果表明，该方法在1.6～30?000?ng/mL范围内线性良好，R2＞0.999；定量限分别为β-乳球蛋白50?μg/g、αs1-酪蛋白3.2?μg/g、αs2-酪蛋白40?μg/g；平均回收率为86.41%～98.60%，相对标准偏差不大于8.95%；基质效应在86.04%～97.48%之间。此方法可应用于含牛奶和不含牛奶的实际商品，旨在鉴别食品中过敏原标签与产品实际过敏原间的差异，降低牛奶过敏消费者的健康隐患。     

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.     

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.     

Detection of adulteration of locust bean gum with guar gum by capillary electrophoresis and polarized light microscopy

Capillary electrophoresis (CE) and polarized light microscopy (PLM) were utilized in the detection of the adulteration of locust bean gum with guar gum. For CE analyses, standards of locust bean and guar gums were extracted with 30% CH₃CN, removing the residual proteins from the gum matrix. A 8.75 mM NaH₂PO₄-20.6 mM Na₂B₄O₇ buffer, pH 9, was used to separate these proteins and to identify marker proteins that were present in the guar gum. These markers did not co-migrate with components in the extracts of mechanically processed locust bean gum, and are used as indicators of adulteration. Using PLM with toluidine blue and iodine staining techniques, unadulterated locust bean gum samples were distinguished from mixed samples through the differential staining of components in locust bean versus guar and tara gums. These experiments in the use of CE and PLM provide orthogonal and complementary methods for the verification of 'true' positives and the elimination of 'false' positives.     

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     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.