B货翡翠的漫反射红外傅里叶变换光谱法鉴别

对酸处理后注蜡和注胶的翡翠(B 货),漫反射红外傅里叶交换(DRIFT)光谱法是一个有用的非破坏的识别手段。因此,DRIFT 光谱法可用来鉴别天然的未经处理的翡翠与打蜡翡翠(A 货)。DRIFT 光谱中表现出的强吸收峰可用于检测胶和蜡的存在。利用 DRIFT 光谱法对10个翡翠样品进行综合研究,结果表明,其中一些翡翠样品已经过了酸处理、注蜡或注胶处理。该研究结果已被基础宝石学测试和 X 射线光电子分光光度法(XPS)检测所证实,并可与类似的傅里叶变换红外(FTIR)透射光谱法研究结果进行对比。通过对比,发现 DRIFT 光谱法在检测很厚(厚度大于12 mm)的翡翠样品和较薄的、但不透过红外光的 A 货时更具优势。同时也更适用于检测罕见的全包镶的翡翠首饰。     

坐堂咨询珠宝首饰时常见问题问答

笔者应“国家首饰质量监督检验中心”的邀请 ,参加北京２０多个大型百货商场的珠宝首饰义务咨询活动 ,一年多来接待了很多消费者 ,大部分消费者对珠宝首饰知识知道得不多 ,往往在旅游时购买了假冒伪劣产品 ,检测后大呼上当。为普及珠宝首饰知识 ,现将坐堂咨询珠宝首饰时常见的问题以问答方式整理如下。一、问 :什么是翡翠的Ａ货／Ｂ货／Ｃ货 ?它们有什么不同的特点 ?答 :１ 翡翠的Ａ货／Ｂ货／Ｃ货都是天然翡翠 ,这是它们的共同特点 ,以为翡翠Ｂ货与Ｃ货不是天然翡翠的观点是不对的。２ 翡翠Ａ货是指没有经过人工优化处理的天然翡翠。也就是…     

分光光度法测定大豆脂肪氧合酶活性的研究

以分光光度法测定大豆脂肪氧合酶Ｌ－１、Ｌ－２和Ｌ－３的活性。测定Ｌ－１时,测定Ｌ－１时,取第２ｍｉｎ内吸光度的增加值作为吸光度变化率,其线性范围为０．１０～０．４０／ｍｉｎ。测定Ｌ－２时,取第４ｍｉｎ内吸光度的增加值作为吸光度变化率,其线性范围为０．０１～０．１４／ｍｉｎ。测定Ｌ－３时,取第ｌｍｉｎ内吸光度的增加值作为吸光度变化率,其线性范围为０·ｏｆ～０·１４／ｍｉｎ。     

分光光度法检测糖厂汽凝水蔗糖含量

利用分光光度法测定糖厂汽凝水中的蔗糖含量。结果表明：在一定条件下,蔗糖被浓硫酸脱水生成的糠醛或其衍生物,可与α-萘酚缩合成紫色的化合物,其颜色深度与蔗糖浓度成正比。蔗糖含量在0—50ug／15ml范围内遵守郎伯比尔定律,检测限为2u．g／L,方法的表观摩尔吸光度为：2．21×10^4L·mol^-1·cm^-1,精密度（RSD）小于3．5％,样品加标回收率在99．72％-100．62％之间,结果符合要求。     

“新型”处理翡翠(注蜡)实验及鉴定

近年来,翡翠市场上出现了一种“新型”处理翡翠(注蜡).这种注蜡翡翠与未注蜡翡翠在肉眼上无明显差别,且结构未遭到破坏,但在紫外荧光灯下和红外光谱中有异常现象.这对实验室检测定名及销售市场产生了很大的困扰.为此,在对“新型”处理翡翠(注蜡)实验研究的基础上,采用宝石学常规检测、高倍率放大观察和光谱学测试对30件注蜡前、后的翡翠样品进行了综合研究.结果显示,肉眼(放大)观察时,这种注蜡翡翠的颜色、结构基本未遭破坏,但在紫外荧光灯和DiamondViewTM下具有蓝白色荧光,红外光谱中具有2 850,2 920,2 956 cm-1处的强吸收峰.根据“GB/T 16553-2010”《珠宝玉石鉴定》中翡翠优化处理定名的相关规定,本研究的注蜡翡翠应定名为翡翠.     

翡翠虽好 良玉难求——专家教你如何识别低档玉

翡翠玉器市场上大量出现处理翡翠（即Ｂ货和Ｃ货）已让不少消费者感到头痛，谁知近来又出现了一种“八三玉”，某些商家将之冒充优质翡翠出售，上当的消费者更是懊恼又气愤。“八三玉”究竟是何物？记者就此请教了上海市宝玉石协会理事许耀明教授。许耀明介绍道：翡翠的科...     

国外期刊文摘

用在线离子交换富集分光光度流动喷射法测定葡萄酒中的铅Teresal．M．S．LopesetalAnalyst，1996（12）：1047～1050葡萄牙和巴西提出用在线离子交换分光光度法测定葡萄酒中的铅。采用Chelex－100树脂微交换柱（200～400目）富集铅，其色谱反应是基于铅、孔雀绿和碘化物之间生成三元络合物。每小时可处理45个酒样（25～500μg／LPb），结果与用ETAAS法测得的差不多。本法测定精度为RSD＜2．6％，检测限为12pg／L，取样速率为45个／h。（徐小妹，许孙曲）用循环连续液液苹取法测定酒中的酣类化合物E．R．BrhetalAnalyst：1996（121…     

翡翠的优化处理及鉴别特征

一、翡翠A货 翡翠的A货是指天然产生,未经人为利用物理、化学方法破坏其内部结构或有物质带入带出的翡翠。经过传统工艺的弱酸、弱碱去脏,并注蜡的翡翠也为A货。     

"起荧"翡翠的矿物学特征及光学原理研究

采用X射线粉末衍射仪（XRD）、傅里叶变换红外光谱仪（FTIR）、X射线能谱仪（EDS）和扫描电子显微镜（SEM）等测试仪器对目前珠宝市场价值较高的“起荧”翡翠样品进行了矿物学、岩石学研究,并对其“起荧”现象的光学原理进行了初步探讨。研究结果表明,翡翠（包括硬玉质翡翠和绿辉石质翡翠）的“起荧”现象与其化分成分无必要关联。翡翠发生“起荧”现象的必要条件为：1．翡翠饰品应整体或局部被切磨成弧面琢型,其弧面琢型的高度对“起荧”现象的强弱有一定的影响;2．翡翠饰品的表面抛光精良;3．翡翠的矿物颗粒大小基本上在0．05～0．14mm范围内。     

油茶籽油质量浓度与紫外吸光度之间的相关性研究

采用紫外吸收光谱法对不同波长下油茶籽油质量浓度与吸光度的关系进行探讨,对油茶籽油质量浓度与吸光度的定量关系进行了研究。结果表明:当油茶籽油的质量浓度为1～10 mg/m L、0. 1～1 mg/m L、10～100μg/m L、1～10μg/m L时,测定波长分别取240、215、210、200 nm,此时吸光度与样品质量浓度具有良好的线性关系;最大吸收峰所对应的波长及吸光度均与样品质量浓度具有对数关系。同时,将此方法与传统混合油质量浓度的测定方法进行对比,发现所得到的测定结果没有显著差异。     

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