HPLC法测桂花中槲皮素的含量

目的:采用高效液相色谱法对桂花提取液中槲皮素含量进行测定。方法:测定条件为色谱柱:ZORBAX Eclipse XDB-C18 Analytical(4.6×250mm 5-Micron);流动相:乙腈-0.2%磷酸(体积比36∶64);流速:1.0 m L·min-1;检测波长:374 nm;柱温:25℃进样量:10μL。结果:测得桂花提取液中槲皮素平均含量为0.6447μg·m L-1,经换算得鲜桂花中槲皮素平均含量为0.3224mg·g-1,平均回收率为99.14%。在进样量为0.006-0.12μg范围内,线性关系良好。结论:该方法准确、灵敏、重现性好,可为桂花槲皮素的定量提供参考。     

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。     

柱前衍生-高效液相色谱法检测食品中的黄曲霉毒素B_1、B_2、G_1、G_2

目的:改进柱前衍生-高效液相色谱法测定食品中的黄曲霉毒素B1、B2、G1、G2。方法:分别用甲醇-水(8∶2,v∶v)或二氯甲烷提取食品中的黄曲霉毒素。提取液经免疫亲和柱净化后,采用三氟乙酸(或甲酸)进行衍生,并利用高效液相色谱仪进行测定。结果:黄曲霉毒素B1、B2、G1、G2的检出限分别为0.2、0.2、0.2、0.2μg/kg;在低、中、高加标浓度下的回收率分别为81.0%~94.1%、75.6%~92.0%、75.0%~92.4%、77.6%~91.3%。结论:改进后的柱前衍生-高效液相色谱法克服了样品基质的干扰,测定结果更准确。     

固相萃取—超高效液相色谱法测定水产品中6种氟喹诺酮类药物残留

基于固相萃取(SPE)和超高效液相色谱(UPLC)技术,建立可同时测定水产品中诺氟沙星、氧氟沙星、环丙沙星、培氟沙星、洛美沙星、恩诺沙星6种氟喹诺酮类药物残留量的检测方法。经优化后的检测过程及参数为:样品匀浆后以磷酸盐缓冲液为提取剂,提取液经SPE净化、氮吹浓缩后,残渣用0.2%的甲酸水溶液溶解供UPLC分析;选用BEH C18(1.7μm,2.1mm×50 mm)色谱柱,以体积比为937的0.05mol/L柠檬酸+0.1 mol/L乙酸铵缓冲液-乙腈为流动相,流速为0.42mL/min,进样体积为0.2μL,柱温为50℃,荧光检测器检测波长λex=278nm、λem=465nm。该方法简单有效,添加回收率为63.69%～90.83%,最低检出限为0.5～1.8μg/kg,相对标准偏差均低于10%。     

离子排斥色谱法测定纺织品中丙烯酰胺

采用离子排斥色谱法测定纺织品中丙烯酰胺的残留量。以水为溶剂提取样品中的丙烯酰胺,提取液过滤后经离子排斥色谱分离测定丙烯酰胺含量。色谱条件为:IonPac ICE-AS1柱(250mm×4.0mm,5μm);流动相为乙腈和10mmol/L甲酸水溶液;检测波长202nm;流速0.15mL/min。该方法在20～1 000μg/L浓度范围内具有良好线性关系,相关系数为0.9998,方法检测限为0.4mg/kg,回收率在93.9%～103.0%之间,相对标准偏差在1.85%～3.75%之间。     

HPLC-MS法测定罗汉果中10种氨基甲酸酯类农药

建立HPLC-MS/MS分析方法,同时测定罗汉果中10种氨基甲酸酯农药残留量。样品经有机溶剂超声提取,提取液浓缩后经固相萃取小柱净化,采用梯度洗脱分离,色谱系统条件为VP-ODS色谱柱(2.0 mm×150 mm,5μm),柱温40℃,流速0.2 m L/min,进样量10μL,以多反应检测模式监测。考察了3个水平添加下(250、500、1000μg/L),10种农药的平均回收率为84.5%~111.7%,相对标准偏差为1.8%~7.3%,检测限在0.1μg/kg~2.0μg/kg。该方法准确、快速、抗干扰能力强,可作为罗汉果中氨基甲酸酯类农药残留的测定。     

高效液相色谱法测定牛羊杂碎等肉类中嘌呤及尿酸

建立同时测定肉类食品中尿酸、鸟嘌呤、次黄嘌呤、黄嘌呤和腺嘌呤的高效液相色谱分析方法,并测定肉类样品中上述4种嘌呤及尿酸的含量。色谱条件:资生堂CAPCELL PAK-C_(18)(4.6 mm×250 mm,5μm)色谱柱,柱温30℃;流动相为7×10~(-3)mol/L KH_2PO_4-H_3PO_4(pH=3.83),流速1.0 mL/min;检测器为紫外检测器,检测波长254 nm;进样量10μL。结果:在上述条件下4种嘌呤和尿酸分离和测定效果良好,4种嘌呤和尿酸的质量浓度和峰面积在0.05~50μg/mL线性范围内线性关系良好,相关系数均在0.999 6以上,检出限在0.010~0.024μg/mL之间,精密度检测RSD为0.25%~0.81%,各组分回收率为92.0%~105.0%,方法精密度RSD为6.27%~11.09%。结论:该方法简便,快捷,可靠,各组分分离度好,可应用于肉类食品中嘌呤和尿酸的同时分析测定。     

鸡蛋中聚醚类抗生素残留检验方法研究

建立了柱后衍生高效液相色谱法同时检测鸡蛋中莫能菌素和盐霉素残留量的方法。采用ZORBAXSB-C18(4.6mm×250mm,i.d,5μm)色谱柱,选择甲醇/5%冰乙酸(体积比90∶10)为流动相,紫外检测波长为520nm。莫能菌素和盐霉素在柱后分离后与衍生试剂1(硫酸)和衍生试剂2(香草醛)在不同的反应器中先后分别发生反应。在鸡蛋中添加莫能菌素和盐霉素的量分别为0.1/0.2μg/g、0.2/0.5μg/g、0.5/1.0μg/g时,莫能菌素的回收率为84.9%～92.1%,RSD为1.56%～2.17%;盐霉素的回收率为80.8%～91.4%,RSD为1.66%～3.47%。该方法灵敏、准确,适合于鸡蛋中微量莫能菌素和盐霉素残留量的测定。     

高效液相色谱法测定水产品中呋喃唑酮残留量的分析研究

建立了测定水产养殖动物可食部分中呋喃唑酮残留量的快速、准确、低检出限的高效液相色谱分析方法.色谱柱选择Novapak ODS柱3.9×150mm(4μm);流动相为乙腈 0.1%的磷酸=15 85;固定柱温30℃.测定的回收率均在80%以上,相对标准偏差小于6.64%,最低检出限为5×10-3mg/kg.     

不同秋果型树莓中槲皮素和山奈酚含量的测定

通过高效液相色谱法测定,不同秋果型树莓中槲皮素和山奈酚的含量。高效液相色谱法的测定条件:色谱柱为安捷伦18反相色谱柱(250 mm×4.6 mm,5μm),甲醇-1%乙酸溶液为流动相,流速为1.000 mL/min,测定波长254 nm,进样量10μL。结果表明:槲皮素和山奈酚分别在0.11μg/mL～11μg/mL(R~2=0.999 8);0.11μg/mL～27.5μg/mL(R~2=0.999 7)呈良好的线性关系;加样回收率分别为为0.76%、0.91%。     

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.     

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%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press