TLC-SERS法快速筛查猪尿中磺胺类抗生素

采用薄层色谱法(TLC)与表面增强拉曼光谱(SERS)联用技术,建立猪尿中磺胺类抗生素残留的快速筛查方法。用阴性猪尿样本模拟阳性样品,以氯仿-乙醇-石油醚(1:1:2)为展开剂,利用TLC将猪尿中的抗生素与猪尿基质初步分离。以785 nm激光为激发波长,金溶胶为表面增强剂,采用SERS技术对分离出的抗生素沉积斑点进行检测。结合密度泛函理论,得到定性定量分析猪尿中磺胺嘧啶分子特征峰877 cm~(-1)和994 cm~(-1)、磺胺二甲嘧啶分子特征峰661 cm~(-1)、磺胺噻唑分子特征峰862 cm~(-1)和1127 cm~(-1)。该方法检测猪尿中磺胺嘧啶、磺胺二甲嘧啶和磺胺噻唑的最低检测浓度分别为0.1、0.1、0.2 mg/L。且TLC技术可实现猪尿中混合抗生素的分离,当猪尿中3种混合抗生素点样沉积量为0.01μg时,各抗生素的特征峰均清晰可辨。由此可见,TLC-SERS技术可用于猪尿中混合抗生素残留的快速筛查。     

QuEChERS-表面增强拉曼光谱联用快速测定豆类蔬菜中马拉硫磷残留

应用QuEChERS前处理方法结合表面增强拉曼光谱(Surface-Enhanced Raman Spectroscopy)检测技术建立了豆类蔬菜(Legume Vegetables)中马拉硫磷(Malathion)残留的快速检测方法。样品以0.1%乙酸乙腈提取,N-丙基乙二胺(PSA)、C18净化剂配合石墨化炭黑(PestiCarb)净化,净化液经表面增强拉曼光谱测定后外标法定量。实验表明:加入表面增强剂后,拉曼光谱图在760cm-1处出现明显的马拉硫磷拉曼特征峰;其特征峰强度与马拉硫磷质量浓度在0.1~8.0μg/mL范围有良好的线性关系;在0.5、1.0、2.0 mg/kg添加水平下,4种豆类蔬菜的平均添加回收率在79.3%~102.1%之间,相对标准偏差(RSD)2.3%~7.8%,定量下限(LOQ)0.2 mg/kg。方法操作简便、高效、环保,符合国家规定的残留限量的检测要求,可用于豆类蔬菜中马拉硫磷残留量的快速测定。     

橙红色砗磲的宝石学特征

近期,市场上出现了一种橙红色砗磲品种,选取具有代表性的橙红色砗磲样品,对其进行了较为系统的宝石学特征及谱学分析研究。采用宝石显微镜观察形貌特征、红外光谱仪检测橙红色砗磲样品种属成分、显微激光拉曼光谱仪分析其颜色,并与市场上较常见金丝砗磲样品进行对比。经分析发现,橙红色砗磲样品的红外光谱谱峰与砗磲一致,拉曼光谱结果显示了橙红色砗磲中文石拉曼特征峰以及1 130 cm~(-1)和1 520 cm~(-1)处与色素有关的拉曼特征峰,与橙红色砗磲的白色部分对比发现其颜色主要与天然有机色素类红萝卜素有关,属于天然颜色成因。     

表面增强拉曼散射法快速检测饮料中碱性嫩黄O

基于表面增强拉曼散射光谱(surface-enhanced raman spectroscopy,SERS)技术建立饮料中碱性嫩黄O定性、定量快速检测方法。通过基质空白对照进行梯度浓度的碱性嫩黄O的SERS检测发现,在780 cm~(-1)处具有明显的碱性嫩黄O特征峰,特征峰强与碱性嫩黄O浓度呈现良好的线性关系,其中碳酸饮料中碱性嫩黄O和功能性饮料中碱性嫩黄O检测的线性范围分别为2.5~20μg/L与5~60μg/L,最低检出限分别为2.5μg/L和5μg/L,回收率分别为98.4%~104.1%,101.1%~102.7%,相对标准偏差均小于5%。该方法重现性较好、全程分析时间短、前处理方法简便、操作简单便、设备便于携带,可有效用于饮料中碱性嫩黄快速检验监督。     

高效液相色谱法测定熟肉制品中苯甲酸、山梨酸、胭脂红和诱惑红含量

目的建立高效液相色谱法测定熟肉制品中食品防腐剂(苯甲酸和山梨酸)和色素(胭脂红和诱惑红)的分析方法。方法样品经组织捣碎、超声提取、过滤、定容,利用高效液相色谱法检测,甲醇水混合溶液作为流动相,二极管阵列检测器(photo-diode array,PDA)检测,苯甲酸和山梨酸的检测波长为230nm,胭脂红和诱惑红的检测波长为508nm。结果苯甲酸和山梨酸在0.05~0.30mg/mL,胭脂红和诱惑红在2.5~12.5μg/mL范围内,均具有良好的线性关系良好,相关系数r均0.9999。苯甲酸和山梨酸的最低检出限(limit of detection,LOD)范围为1.2~1.8 mg/kg,最低定量限(limit of quantification,LOQ)范围为3.6~5.4mg/kg;胭脂红和诱惑红的LOD范围为0.05~0.1mg/kg,LOQ范围为0.15~0.3 mg/kg。平均加标回收率为94.8%~96.9%,相对标准偏差(relative standard deviation,RSD)为2.4%~4.1%。100份熟肉制品样品中,5份有山梨酸检出,检出率为5.0%,检测结果范围为0.030~0.65g/kg;1份有胭脂红检出,检出率为1.0%,检测结果为0.0023g/kg;3份有诱惑红检出,检出率为3.0%,检测结果范围为0.0036~0.0083g/kg;苯甲酸在所有熟肉制品样品中均未检出。结论该方法灵敏度高,回收率高,检测限低,符合分析要求,适合检测熟肉制品中的苯甲酸、山梨酸、胭脂红和诱惑红。     

全自动固相萃取净化测定肉制品中日落黄、诱惑红的研究

建立了全自动固相萃取净化——高效液相色谱法测定肉制品中日落黄、诱惑红的分析方法。利用全自动固相萃取仪对肉制品中样品提取液进行净化,通过高效液相色谱对净化液进行分析,采用Welch,XB-C18(4.6×250mm,5μm)色谱柱,流动相:乙酸铵(0.02mol/L)-甲醇的梯度洗脱,流速1.0m L/min,检测波长254nm。日落黄、诱惑红在0.1~50.0μg/m L范围内线性良好,日落黄、诱惑红的平均回收率分别为75.8%~88.5%、81.0%~95.0%,RSD值分别为1.6%~1.9%、1.5%~1.7%,最低定量限分别为0.040mg/kg、0.030mg/kg。方法的回收率好、精密度高,并且方法简便、高效,一次能处理多个样品,大大降低人力成本和提高检测效率,可应用于测定肉制品中的合成色素。     

SERS检测三聚氰胺的不确定度分析

不确定度是一类表征测试结果可靠性的重要参数,对于规范试验操作具有重要意义。表面增强拉曼光谱技术(surface enhanced Raman spectroscopy,SERS)作为一种用于物质定性和半定量分析的分子振动光谱,具有快速、简便和灵敏度高等特点,在食品安全与质量控制领域中广泛应用。利用SERS技术对三聚氰胺进行测定试验,并对该方法的不确定度进行分析。经辨识,确认715 cm~(-1)处的峰为三聚氰胺的特征峰,该峰的峰强与三聚氰胺的浓度呈正相关。选取675 cm~(-1)处的峰为内标峰,在0.1μg/mL~5.0μg/mL范围内,以I715/I675和浓度为参数进行线性回归分析。标准方程相关系数达到0.995 4,该方法的检出限为0.068 6μg/mL。围绕标准工作曲线的建立,分析SERS测定三聚氰胺结果的不确定度来源并对其进行评定。通过不确定度分析,为确保测定结果的可比性与溯源性提供了参考价值。     

SERS法快速检测食品中新红

采用多孔银丝作为表面增强拉曼(SERS)基底,建立了快速检测食品中人工合成着色剂新红的分析方法。食品样品经提取、净化去除基质中大分子干扰物,采用25 mV/s扫速制备的银丝基底静置萃取1 min后即进行拉曼测试。结合固体标准品拉曼谱图和密度泛函理论计算结果对新红表面增强拉曼谱图中的特征峰进行了归属,以对新红进行定性和定量测定,结果表明1592cm~(-1)处的峰强度与新红浓度的线性范围为(1×10~(-6)~2×10~(-5))mol/L,检出限为5×10~(-8) mol/L。该方法原位萃取、测试时间只需2 min,回收率在87.8%~93.8%,相对标准偏差小于6.5%可应用于食品样品中新红的快速检测。     

果酱和罐头中诱惑红的高效液相色谱测定法

建立果酱和罐头中诱惑红的高效液相色谱测定方法。样品中的诱惑红色素经提取后在酸性条件下被聚酰胺粉吸附,在碱性条件下解吸附,以甲醇和乙酸铵溶液为流动相,等度洗脱,紫外检测器检测,波长254nm,以相对保留时间定性,色谱峰面积定量。浓度与峰面积线性关系良好(r=0.9995),回收率83.0%~105.0%,相对标准偏差小于20%,最低检出浓度为2.5mg/kg;该方法操作简便、灵敏、准确,适用于果酱和罐头中诱惑红的检测。     

基于拉曼光谱的胡萝卜中β-胡萝卜素的快速无损检测

目的利用实验室自行搭建的拉曼点扫描系统,以市售新鲜胡萝卜为研究对象,建立一种快速无损检测胡萝卜中的β-胡萝卜素的预测模型。方法在胡萝卜长度方向每隔1 cm进行点扫描,样品点扫描拉曼光谱曲线均先采用Savizky-Golay 5点平滑法去噪后再用Baseline方法进行去除荧光背景预处理,最后取平均值作为样品的拉曼光谱。胡萝卜中的β-胡萝卜素标准理化值按照国家标准GB/T 5009.83-2003法进行测定,理化值与1521 cm~(-1)和1156 cm~(-1)处β-胡萝卜素的拉曼特征峰强建立了多元线性回归模型。结果模型校正集的相关系数(R_C)和均方根误差(RMSEC)分别为0.9249和12.04 mg/kg,验证集的相关系数(RP)和均方根误差(RMSEP)分别为0.9155和1 1.47 mg/kg。结论基于拉曼光谱完全可以实现新鲜胡萝卜中β-胡萝卜素含量的检测,为新鲜果蔬中β-胡萝卜素含量的定量检测提供技术支撑。     

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