基于表面增强拉曼光谱的鸭肉中己烯雌酚残留检测

采用表面增强拉曼光谱(SERS)法建立了一种快速检测鸭肉中己烯雌酚(DES)残留的方法。采用单因素分析法确定了合成金胶所需的柠檬酸三钠、纳米金胶、含DES的鸭肉提取液和硫酸镁溶液的最优加入量以及拉曼光谱的较佳采集时间。对鸭肉做简单的前处理后,建立鸭肉中的DES残留检测的定量分析模型。再以鸭肉提取液中DES浓度与819cm~(-1)处特征峰峰强建立标准曲线方程,可达到0.5mg/L的最低检测浓度。根据标准曲线方程得到其预测集的决定系数(R~2)为0.969 0,预测均方根误差(RMSEP)为0.728 1mg/L,平均回收率为83%～133%。试验结果表明,该方法可用于鸭肉中DES残留检测。     

鸭肉中强力霉素残留的SERS快速检测

以表面增强试剂OTR202和OTR103作为表面增强拉曼光谱(SERS)的活性基底,探索建立一种鸭肉中强力霉素(DC)残留的SERS检测方法。首先对DC水溶液、鸭肉提取液和含DC的鸭肉提取液的SERS光谱特征进行了对比分析。然后研究了含DC的鸭肉提取液加入量和吸附时间分别对SERS信号强度的影响,确定了含DC的鸭肉提取液加入量为20μL,最佳吸附时间为1 min。最后取1270与1242 cm~(-1) SERS信号强度比(I_(1270)/I_(1242))来建立预测鸭肉提取液中DC残留的标准曲线。试验结果表明,鸭肉提取液中DC质量浓度范围为4~30 mg/L时,鸭肉提取液中DC质量浓度与I1270/I1242之间呈良好的线性关系。应用得到的标准曲线对含不同质量浓度DC的鸭肉提取液进行预测,预测集的相关系数(r)和预测均方根误差(RMSEP)分别为0.9762和3.0036,鸭肉提取液中DC的检出限可达1.346 mg/L,这说明本文研究方法用于鸭肉中的DC残留快速检测是可行的。     

表面增强拉曼光谱快速检测四环素水溶液

目的为实现水中四环素残留的快速检测,探索建立四环素水溶液的表面增强拉曼光谱(surface enhanced Raman spectroscopy,SERS)检测方法。方法以OTR202和OTR103作为表面增强基底,分析四环素水溶液的SERS光谱,应用自适应迭代惩罚最小二乘法(air-PLS)扣除SERS的荧光背景,探讨样品加入量对SERS信号强度的影响,以1274 cm-1作为特征峰建立四环素水溶液的标准曲线。结果确定了四环素水溶液的加入量为20μL,建立的线性回归方程Y=257.47X+85.165,相关系数r为0.9897。结论本研究方法无需前处理,简便快捷,为后续水中四环素残留快速现场检测奠定了良好基础。     

SERS检测牛奶中磺胺二甲嘧啶

目的建立磺胺二甲嘧啶水溶液的表面增强拉曼光谱(SERS)检测方法。方法利用便携式拉曼光谱仪测量磺胺二甲嘧啶水溶液的拉曼特征峰,并对峰位进行了归属和指认。结果磺胺二甲嘧啶的拉曼特征峰主要位于638,685,719,828,996,1089,1142,1343,1508,1592,1636 cm-1处,水溶液中磺胺二甲嘧啶的检测限为0.5 ppm,牛奶中磺胺二甲嘧啶的检测限为5 ppm。建立了牛奶溶液中磺胺二甲嘧啶SERS特征峰强与浓度的函数关系,通过非线性拟合,得到曲线方程y=142.23x-229.12,R2=0.996,进而为牛奶中磺胺二甲嘧啶的半定量分析奠定基础。结论 SERS具有快速、简便、准确等优点,有望在磺胺二甲嘧啶的鉴定和检测中使用。     

表面增强拉曼光谱技术快速检测鸭肉中的土霉素

目的采用纳米金胶和OTR103作为表面增强拉曼光谱(surface-enhanced Raman spectroscopy,SERS)的活性基底,实现鸭肉中土霉素残留量的快速检测。方法首先使用自适应迭代惩罚最小二乘法(adaptive iterative re-weighted penalized least squares,air-PLS)扣除SERS测定过程中的荧光等背景信号,确定鸭肉中土霉素检测的特征峰。然后应用单变量分析法对纳米金胶、待测样品、OTR103的加入量和吸附时间进行优化,确定最佳实验条件。结果拉曼位移为1271 cm~(-1)处的特征峰可以作为鸭肉中土霉素残留检测的拉曼特征峰,纳米金胶、待测样品和OTR103的最适加入量分别为0.7 m L、70μL和100μL,最佳吸附时间为5 min。鸭肉中的土霉素浓度范围为0.2~22.0 mg/L时,土霉素浓度(X)与其在1271 cm~(-1)处的SERS特征峰强度(Y)之间有良好的线性关系,线性回归方程为Y=245.24X+647.29,决定系数(RC2)为0.9891,检测限为0.2 mg/L。预测集样本中土霉素含量的真实值与预测值之间的决定系数(RP2)为0.9941,均方根误差(RMSEP)为1.1341 mg/L,回收率为74%~102%。结论该方法可用于鸭肉中土霉素残留的快速检测。     

超高效液相色谱法快速测定原料乳中的双氰胺

建立了超高效液相色谱检测原料乳中双氰胺的分析方法。采用甲醇提取样品中的双氰胺,HILICS色谱柱为分析柱,流动相为乙腈-10 mmol/L乙酸铵(90∶10,体积比),流速0.4 mL/min,检测波长230 nm。双氰胺在0.006 mg/L～10.0 mg/L范围内具有良好的线性关系,标准曲线方程为y=90.336x+0.994 6,R2=0.999 9。方法检出限为0.05 mg/kg,不同添加水平平均回收率在87.0%～91.6%之间,变异系数3.84%(n=6)。此方法操作简便,可在15min内完成快速检测,适用于原料乳中双氰胺残留的快速筛查。     

基于便携式荧光定量PCR仪定量检测驴肉中掺假鸭肉

为建立快速方便的驴肉制品分子鉴定方法,本文以驴肉和常见的掺假肉类(鸭肉)为研究对象,筛选特异性引物和TaqMan探针,利用便携式Mini8 Plus实时荧光定量PCR仪进行灵敏度和特异性实验,通过绘制扩增标准曲线及确定驴肉和鸭肉的质量与DNA比值常数,对不同掺入比例(加入定量的鸭肉制成含量分别为20%、40%、60%、80%)的模拟样品和实际驴肉样品进行检测。结果显示,该方法对驴、鸭肉均具有良好的特异性,可以与马、猪、山羊、梅花鹿、牛、鸡、狗肉明显区分;对驴源性DNA成分的检出限为0.01 ng/μL,鸭源性DNA成分的检出限为0.1 ng/μL,对驴肉与鸭肉混合物中鸭肉成分的灵敏度为0.1%(w/w);所建立的标准曲线线性关系良好,驴肉DNA扩增标准曲线:y=-3.584x+27.003,R²=0.9982;鸭肉DNA扩增标准曲线:y=-3.538x+30.907,R²=0.9991;采用已建立的方法对35份驴肉样本进行市场试点调查,发现6份(17.1%)驴肉样本中含有鸭肉成分。以上研究结果说明,该实时荧光定量PCR方法可用于驴肉产品中其他...     

双波长法测定薯芋类农产品中直链淀粉和支链淀粉的含量

目的:建立薯芋类农产品中直链淀粉和支链淀粉的双波长测定法,为品种选育、品质分级、加工应用和标准制定等提供基础数据。方法:研究了直链淀粉和支链淀粉的吸收光谱图,确定二者的最大吸收波长及参比波长。优化了分散剂、乙酸加入量等显色条件及测定条件。结果:直链淀粉标准曲线方程为:y=0.0259x?0.0051,R2=0.9994,线性范围0~33 μg/mL;支链淀粉标准曲线方程为:y=0.0031x+0.0167,R2=0.9965,线性范围0~111 μg/mL。直链淀粉的检出限为0.093 μg/mL,定量限0.28 μg/mL;支链淀粉的检出限为0.079 μg/mL,定量限0.24 μg/mL,直链淀粉回收率为90.0%~100.0%;支链淀粉回收率为88.0%~108.0%。结论:双波长法简单易行,结果准确可靠,适用于薯芋类农产品中直链淀粉和支链淀粉的分析检测。     

高效排阻液相色谱法分析大豆7S和11S球蛋白的分子质量和纯度

本文采用SE-HPLC法定量分析大豆7S和11S球蛋白的分子质量和纯度。首先,对SE-HPLC的色谱条件进行优化,最佳的SE-HPLC色谱条件是:洗脱液(水/乙腈)70/30,洗脱液流速1.0 m L/min,进样量10μL。其次,绘制分子质量分析的标准曲线,分子质量标准曲线方程为Log(M)=-0.222 1 x+3.878 9,线性相关系数为R~2=0.996 9。以10倍信噪比确定定量限,得到7S(y=299.59x+3.771 2,R~2=0.979 2)和11S(y=197.08x+4.148 5,R~2=0.986 1)纯度分析标准曲线方程。最后根据分子质量和纯度分析的标准曲线方程计算大豆7S和11S球蛋白的分子质量和纯度。将所提纯的7S和11S样品的分子质量与7S和11S标品特征峰分子质量进行比对,表明所提纯样品为7S和11S。本试验所制得7S和11S的纯度分别达到86.3%和92.0%。     

基于MXenes的SERS基底增强拉曼光谱检测柑橘中的福美双

目的:研究基于MXenes(Ti3C2Tx)二维材料的表面增强拉曼散射(SERS)基底的农残快速检测方法。方法:采用氟盐刻蚀法制备单层的带负电的MXenes二维材料,再合成正电荷表面活性剂CTAC修饰的30 nm金纳米粒子(AuNPs),通过静电吸附作用,制备MXenes负载金纳米的二维复合基底(AuNPs/MXenes)。以罗丹明6G(R6G)作为拉曼探针分子,优化AuNPs与MXenes胶体溶液混合体系的浓度比例,用于福美双的检测。结果:AuNPs/MXenes的拉曼增强因子为1.7×105,表现出良好的SERS活性,以1 379 cm-1处福美双拉曼特征峰的强度与福美双农残浓度的对数构建线性关系,得到标准曲线:y=888x+1 151,决定系数R2为0.986,检测限为0.051 ng/mL,低于国家标准5 ng/mL。使用标准的前处理QuEChERS法对柑橘样品进行预处理,实现了真实柑橘样品中的福美双残留的SERS检测,其回收率范围101.1%～122.0%。结论:基于MXenes结构制备的SERS基底,可用于柑橘样品中的福美双检测。     

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