三氯化钛-分光光度法测定决明子蒽醌

提出了三氯化钛-分光光度法测定决明子中总蒽醌含量的新方法。该法是基于在强酸性介质中，亚钛盐可还原蒽醌类化合物，从而使紫色的亚钛盐转变为黄色的钛盐，该物质在349nm处有最大吸收。该法的线性范围为6～40μg/mL，r=0.9996，回收率为96％～98％。     

高效液相色谱法测定发芽米胚芽中的γ-氨基丁酸

建立一种高灵敏度的邻苯二甲醛(OPA)柱前衍生荧光检测高效液相色谱法测定发芽米胚芽中γ-氨基丁酸(GA-BA)含量的方法。色谱柱为Shimadzu VP-ODS C18柱(250mm×4.6mm,5μm),流动相:0.05mol/L乙酸钠∶甲醇=60∶40,荧光发射波长λex 338nm,激发波长λem430nm。方法的线性范围为0.10～1.0μg/mL,检出限为0.005μg/mL。日间和日内测定的精密度分别为1.36%和2.54%,加标回收率在98.5%～99.8%。该法简便、快速、灵敏度高,可用于发芽米胚芽中GABA的质量控制。     

荧光光度法测定鱼肉中的环丙沙星

采用荧光光度法测定了鲫鱼、鳗鱼、鲤鱼和罗非鱼肌肉组织中的环丙沙星药物残留量。样品用酸性乙腈提取,正己烷脱脂,水相在HAc-NaAc(pH4.5)缓冲溶液中,激发波长λex275nm,荧光测定波长λem450nm下用荧光光度法测定环丙沙星含量,环丙沙星的线性范围10￣150μg/L,相关系数r=0.9987,检出限为5μg/L。回收率为74.0%￣90.6%。变异系数为2.96%￣7.54%。     

高效液相色谱法测定红曲醋中桔霉素含量

目的:测定红曲醋中的桔霉素含量;方法:用氯仿萃取红曲醋中的桔霉素,将萃取液进行浓缩,使用大孔吸附树脂对浓缩液进行柱层析净化,层析洗脱液经反相高效液相色谱分离,用荧光检测器以λex=331 nm,λem=500nm波长检测,采用外标法定性、定量.结果:在0.103μg/mL～1.648μg/mL浓度范围内桔霉素与荧光检测器响应值呈良好线性关系,最低检出量1.26ng,平行实验RSD为3.46%,重复实验RSD为4.28%,加标回收率91.60±4.23.结论:本方法可用于红曲醋中桔霉素的检测.     

高效液相法检测几种米醋中的桔霉素含量

实验采用岛津ODS柱(Hypersil ODS 2,5μm,250mm×4.6),乙腈(色谱纯)∶超纯水为30∶70为流动相。流速0.8mL/min荧光检测波长为λex=331nm,λem=500nm。在0.01～100μg/mL浓度范围内,桔霉素浓度与荧光检测器响应值成良好线性关系,Y=78253x+37970(R2=0.9991)。样品加标回收率达到91.09%～101.2%。结果表明:米醋类食品较为安全,桔霉素含量最高的是米醋1,含有1.3361μg/mL桔霉素,含量最低的是米醋5,0.0158μg/mL。     

同步荧光法测定荷叶中总黄酮含量

根据槲皮素能与铝离子形成稳定的荧光络合物,建立同步荧光法测定荷叶中总黄酮含量的方法。以槲皮素为标样,选择发射波长与激发波长的波长差△λ为40 nm扫描同步荧光光谱,测定荷叶中总黄酮含量,并进行加标回收试验验证方法的可靠性。试验结果表明,槲皮素浓度在0.008μg/mL~0.40μg/mL范围内与荧光强度具有良好的线性关系,线性回归方程:y=5 780x+3.27,相关系数R为0.999 0。     

三波长分光光度法测定芹菜叶中黄酮的含量

采用三波长分光光度法测定芹菜叶中黄酮的含量，消除了由于芹菜叶中黄酮光谱吸收峰不对称给定量分析造成的影响。并校正了由于干扰组分的吸收光谱具有线性吸收产生的基线倾斜。实验结果回归方程为△A=0．0045C-0．0007相关系数r=0．9996；黄酮的浓度在30～300μg/mL范围内，分别在波长为λ1=460nm、λ2=420nm、λ3=380nm处测吸光度时，则△A与浓度C之间呈良好的线性关系，可按标准曲线法进行定量分析。本法的回收率为96．8％-105．9％，变异系数小于0．49％。方法的准确度与精密度均令人满意，而且操作简便易行。     

Mo(Ⅵ)-HMPF-CTMAB光度法测定食品中微量钼

研究了三元配合物Mo(Ⅵ)-2-羟基-3-甲氧基苯基荧光酮(HMPF)-CTMAB的显色条件.最大吸收波长λmax=525.00nm,试剂最大吸收波长为λmax=465.00nm,对比度60nm,ε525=1.30×105L·moL-1·cm-1,钼的浓度0～15μg/25mL,服从比尔定律,该体系选择性好、方法简便、快速,用于食品中微量钼的测定,结果令人满意.     

减肥茶中总蒽醌含量的比较研究

建立减肥茶类保健食品中总蒽醌含量的紫外分光光度测定方法,比较其直接测定与经沸水浸泡后总蒽醌含量的变化.利用蒽醌类化合物在碱性条件下显红色或紫红色的特性,在525 nm波长处测定吸光度.直接测定和沸水浸泡液中总蒽醌含量有差别.减肥茶经沸水浸泡后,测得总蒽醌含量低于直接测定.     

Zn2+-邻菲啰啉-刚果红体系双波长光度法测定食盐中锌含量

增敏剂β-环糊精存在下,Zn2+与邻菲啰啉(phen)和刚果红(CR)在pH 7.0 NH4Ac缓冲溶液中反应生成稳定的离子缔合物[Zn(phen)3 ]CR,使刚果红褪色,574 nm处出现正吸收峰,502 nm处出现负吸收峰.选定测量波长为574 nm,参比波长为502 nm,据此建立了双波长光度法测定微量锌的新方法.表观摩尔吸光系数为9.8×104 L/mol/cm,线性范围为0～0.32μg/mL,检出限为5.7 μg/L.方法用于测定锌强化营养盐和健康平衡盐中锌含量,相对标准偏差为0.70％～0.83％ (n=5),回收率为99.37％～100.04％.     

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