微波消解-石墨炉原子吸收光谱法测定壳聚糖膜中铜离子含量

目的：建立微波消解-石墨炉原子吸收光谱测定壳聚糖膜中铜离子含量的方法。方法：采用微波消解法对样品膜进行消解,在波长327.4 nm处,用石墨炉测定样品模中铜离子的含量。结果：本方法线性关系良好,相关系数r2=0.999 3,检出限为0.096 mg/g。铜离子回收率为72.78%～90.91%。结论：该方法具有快速、简单、准确、无污染等优点,可用于测定壳聚糖膜对铜离子的选择性吸附量。     

微波消解-石墨炉原子吸收光谱法测定大米中铬

建立微波消解-石墨炉原子吸收光谱法测定大米中重金属铬含量的方法。采用微波消解法对样品进行消解,用石墨炉在波长357.9 nm处测定样品中铬的含量。结果表明,该方法线性关系良好,相关系数为0.999 7,检出限为0.006 mg/kg,定量限为0.02 mg/kg,回收率为81.6%～93.1%。该方法具有快速、简便、准确等优点,可用于大米中铬的含量测定。     

微波消解——石墨炉原子吸收光谱法测定兔皮中的铅和铜

建立了微波消解-石墨炉原子吸收光谱法测定兔皮中微量铅和铜的方法。采用微波消解技术,在阶梯升温和加热条件下,用硝酸和双氧水消解兔皮样品,消解后的样液中的铅和铜采用石墨炉原子吸收光谱法测定。试验结果表明:铅浓度在0～60.0μg/L、铜浓度在0～100.0μg/L范围内呈良好的线性关系,相关系数铅R2=0.9998,铜R2=0.9995;最低检出限铅为0.0688mg/kg,铜为0.0405mg/kg;对样品进行8次重复性测定,其相对标准偏差铅和铜分别为:1.47%和2.84%;铜的回收率在95.8%～100.3%之间,铅的回收率在97.0%～104.1%之间,该方法具有操作简便、测定快速、准确度高的优点,适用于兔皮中微量铅和铜的日常批量检测。     

复配膨松剂中铝元素含量测定的研究

目的:建立微波消解-石墨炉原子吸收分光光度法测定复配膨松剂中铝元素含量的方法。方法:样品经硝酸-过氧化氢溶液微波消解后,采用石墨炉原子吸收分光光度测定复配膨松剂中铝元素的含量。结果:该方法线性良好,相关系数为0.998;铝元素的检出限为0.24 mg/kg;回收率在85.5%~97.7%之间;相对标准偏差≤3.8%(n=6)。结论:该方法操作简单、灵敏度高、检出限低,满足复配膨松剂中铝元素含量的测定。     

石墨炉法测定食用明胶铬时三种前处理的比较

为找到适合原子吸收光谱法测定食用明胶铬含量的前处理方法,对干式消解法、微波消解法和湿式消解法进行对比。结果发现,干式消解法使得明胶标准物质(铬含量1.5±0.15 mg/kg)中的铬有较大的损失,测定结果仅为0.91 mg/kg,测定结果需用回收率进行校正;微波消解法和湿式消解法的测定结果分别为1.40和1.61 mg/kg,方法检出限分别为0.08和0.12 mg/kg,精密度(n=7)分别为3.3%和2.2%,结果准确可靠。在使用GB 5009.123—2014原子吸收石墨炉法测定食用明胶中的铬时,应优先采用微波消解和湿式消解的样品前处理方法。     

微波消解-原子吸收分光光度法测定保健食品中铝元素含量

目的建立微波消解-石墨炉原子吸收分光光度法测定固体、液体和软胶囊3种基质的保健食品中铝元素含量的分析方法。方法前处理方法经实验确定为5 mL硝酸和2 mL过氧化氢(30%,V:V)双溶剂消解,经微波消解仪消解,采用石墨炉原子吸收分光光度测定保健食品中铝元素的含量。结果铝元素在0～500μg/mL的浓度范围内线性关系良好,相关系数为0.998;铝元素的检出限为0.24 mg/kg;回收率为81.2%～98.7%;相对标准偏差小于3.2%(n=6)。结论该方法操作简单、灵敏度高、检出限低,满足保健食品中铝元素含量的测定。     

快速消解-石墨炉原子吸收光谱法测定食品中砷含量

目的 建立快速消解-石墨炉原子吸收光谱法测定食品中砷含量的方法。方法 采用快速消解法消解3类食品,用石墨炉原子吸收光谱法测定砷的含量。结果 本实验测定砷的方法检出限和定量限分别为0.051 mg/kg和0.170 mg/kg。与微波消解-原子荧光法测定结果相比,两种方法测定大米和茶叶的绝对差值占算数平均值分别为7.2%、7.6%,两种方法测定奶粉中砷的结果均为0 mg/kg。快速消解-石墨炉原子吸收光谱法的回收率在83.1%~94.4%。结论 本实验建立的快速消解-原子吸收光谱法测定食品中砷的检测方法准确、可靠,适用于食品中砷含量的检测。     

接装纸中镉、铬、镍的石墨炉原子吸收光谱测定

建立了微波消解-石墨炉原子吸收法测定烟用接装纸中镉(Cd)、铬(Cr)、镍(Ni)含量的方法,并采用该方法测定了44个牌号接装纸样品中的Cd、Cr、Ni含量.结果表明:①Cd、Cr、Ni元素的平均回收率分别为102.2%、101.9%和102.2%;RSD分别为4.40%、3.96%和4.71%;检出限为0.009、0.014、0.016 mg/kg;②所测接装纸样品中Cd的含量都在1 mg/kg以下,约23.7%接装纸样品的Cr含量超过15 mg/kg,只有1个样品的Ni含量超过5 mg/kg.     

微波消解-石墨炉原子吸收光谱法检测大米中硒元素的含量

为了建立一种微波消解-石墨炉原子吸收光谱法测定大米中硒含量的方法,以微波消解为前处理,并以1mg/mL的硝酸镁为改进剂,采用石墨炉原子吸收光谱法进行硒的测定。此方法的标准曲线的回归方程为:Y=0.0378X-0.0051,R=0.9983,线性范围为2.5-15ng/mL,检出限为1ng/mL,精密度(RSD)为1.64%,重现性(RSD)为3.59%。样品的加标回收率在92.0%-101.0%。     

微波消解-原子吸收光谱法测定羧基麦芽糖铁中铅和砷

目的建立羧基麦芽糖铁中铅和砷含量测定的方法。方法采用微波消解法处理样品,石墨炉原子吸收光谱法(GTA-AAS)标准加入法测定铅含量,氢化物发生-原子吸收光谱法(HG-AAS)测定砷含量。结果铅浓度在5.0～50.0μg/L,砷浓度在1.0～10.0μg/L范围内线性关系良好,相关系数分别为0.9999,0.9998;铅检出限为0.68μg/L,砷检出限为0.1μg/L;铅测定精密度RSD为3.91%,砷测定精密度RSD为4.31%;铅回收率96.8%～101.3%,砷回收率95.8%～98.9%。结论该测定方法准确、灵敏度高,适用于含铁量高的营养品中重金属元素的检测。     

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