利用拉曼光谱技术识别溴氰菊酯和啶虫脒农药的研究

目的初步建立溴氰菊酯农药和啶虫脒农药的拉曼光谱研究方法。方法利用激光拉曼光谱技术,将农药溶液装满铝盒,采集农药溶液的拉曼光谱曲线,运用自主编写的程序对光谱曲线进行预处理,以去除光谱噪音并扣除荧光背景,进而探讨溴氰菊酯农药和啶虫脒农药的快速无损检测方法。结果溴氰菊酯农药和啶虫脒农药的拉曼特征频率较为丰富,选取574 cm-1、736 cm-1处的拉曼信号可识别溴氰菊酯农药,检测限为2500mg/kg。选取752 cm-1、840 cm-1处的拉曼信号可识别啶虫脒农药,当溶剂的丙酮-水比例为1:5时,最适合作为检测溶剂配置啶虫脒农药溶液,为下一步确定啶虫脒检测限奠定基础。结论本研究对实现拉曼光谱技术检测果蔬表面溴氰菊酯农药和啶虫脒农药具有重要意义。     

拉曼光谱技术检测苹果表面残留的敌百虫农药

建立苹果表面残留的敌百虫农药的拉曼光谱无损检测技术。方法 利用激光显微拉曼光谱技术, 以苹果为载体, 敌百虫农药为研究对象, 探讨苹果表面敌百虫农药的快速无损检测方法。结果 敌百虫农药的拉曼特征频率较为丰富, 选取441 cm?1 (P-O键振动)和620 cm?1(C-Cl键振动)处的拉曼信号可识别苹果表面敌百虫农药残留, 检测限为4800 mg/kg。结论 本研究对实现水果表面敌百虫农药残留的快速、无损伤检测具有重要意义。     

表面增强拉曼光谱法快速测定娃娃菜中啶虫脒残留

基于表面增强拉曼光谱技术和样品前处理技术,建立了娃娃菜中啶虫脒农药残留的快速检测方法。通过试验,对样品前处理过程中萃取盐、净化剂的种类和用量,检测环节中待测液用量、增强基底纳米金用量以及待测液和纳米金混合时间进行优化。在最优条件下,娃娃菜中啶虫脒的表面增强拉曼光谱图在628 cm-1处的特征峰面积与浓度在1.0~60 mg/kg范围内具有良好的线性关系,相关系数为0.9911。该方法的最低检出浓度为0.5 mg/kg。当加标浓度为1,2和5 mg/kg时,回收率在81.0%~110.0%之间,相对标准偏差范围为3.3%~8.5%(n=6)。该方法前处理简单快速、准确度高,能满足娃娃菜中啶虫脒残留的检测要求。     

基于表面增强拉曼光谱技术的苹果汁中溴氰菊酯农药残留的快速定量分析

针对苹果汁中农药残留量超标问题,采用共焦显微拉曼仪,研究了针对苹果汁中溴氰菊酯农残量的快速检测方法。分别以乙醇溶液(对照)、苹果汁溶液为背景溶液,分别采用拉曼光谱技术、表面增强拉曼光谱技术(SurfaceEnhanced Raman Scattering,SERS)采集含农药(溴氰菊酯)的两种样本的拉曼光谱与SERS光谱,并结合一阶导加Norris求导法进行光谱预处理,进而使用偏最小二乘方法建立两种样本溶液中溴氰菊酯残留量的拉曼光谱定量分析模型与SERS光谱定量分析模型,并对两种模型进行对比分析。结果表明,乙醇中溴氰菊酯溶液样本的拉曼光谱定量分析模型的校正集相关系数可达到0.9634,而SERS模型校正集相关系数可达到0.9995,最大误差不超过0.1 mg/kg。苹果汁中溴氰菊酯样本的拉曼光谱模型校正集相关系数为0.9355,最大误差不超过0.02 mg/kg;而SERS模型校正集相关系数为0.9870,最大误差不超过0.1 mg/kg。结果表明,拉曼光谱技术对快速检测苹果汁中的农药残留量具有可行性。     

基于拉曼光谱技术检测菠菜毒死蜱残留的初步研究

目的 基于拉曼光谱技术初步探讨菠菜表面有机磷农药毒死蜱的快速、无损检测新方法。方法 利用本研究自行搭建的拉曼光谱检测系统获取残留不同浓度毒死蜱农药的菠菜光谱曲线, 通过SG-5点平滑减小曲线噪声, 基于最小二乘法的10次多项式拟合法剔除菠菜荧光背景, 并对含有不同浓度毒死蜱农药的菠菜样品拉曼图谱进行比较分析。结果 特征归属为P=S振动的632 cm-1处的拉曼信号可识别菠菜表面毒死蜱农药残留, 其检测限为400 mg/kg, 而且拉曼特征波峰的相对强度与菠菜表面农药残留浓度存在较好的线性关系, 其相关系数为R2=0.92。结论 拉曼光谱技术有望实现叶片类蔬菜的农药残留的快速、无损、定量检测。     

基于拉曼光谱技术检测菠菜的毒死蜱残留

目的基于拉曼光谱技术初步探讨菠菜表面有机磷农药毒死蜱的快速、无损检测新方法。方法利用本研究自行搭建的拉曼光谱检测系统获取残留不同浓度毒死蜱农药的菠菜光谱曲线,通过SG-5点平滑减小曲线噪声,基于最小二乘法的10次多项式拟合法剔除菠菜荧光背景,并对含有不同浓度毒死蜱农药的菠菜样品拉曼图谱进行比较分析。结果特征归属为P=S振动的632 cm-1处的拉曼信号可识别菠菜表面毒死蜱农药残留,其检测限为400 mg/kg,而且拉曼特征波峰的相对强度与菠菜表面农药残留浓度存在较好的线性关系,其相关系数为R2=0.92。结论拉曼光谱技术有望实现叶片类蔬菜的农药残留的快速、无损、定量检测。     

啶虫脒分子印迹荧光传感器的构建及检测研究

作者首先修饰和制备了对啶虫脒农药有特异响应的硅碳量子点（SiCDs）,并以此作为荧光探针开发了可快速检测啶虫脒农药的高灵敏分子印迹荧光传感器SiCDs@MIPs,同时研究了模板与功能单体物质的量比、交联剂添加量、SiCDs包埋量对SiCDs@MIPs检测灵敏度的影响。结果表明,SiCDs@MIPs的最适制备条件为：模板与功能单体的物质的量比为1∶4,交联剂添加量为25 μL,SiCDs包埋量为10 mg。在最优检测条件下,SiCDs@MIPs对啶虫脒的检出限为0.086 μmol/L,线性范围为0.045~0.450 μmol/L,相关系数为0.989,检测时间仅需25 min。进一步将制备的SiCDs@MIPs应用于白菜、番茄和冬瓜中啶虫脒农药残留的检测,回收率可达到73.0%~109.0%。该方法为蔬菜中啶虫脒农药残留的检测提供了新策略。     

紫外光照射降解水中吡虫啉和啶虫脒的研究

本文研究了紫外光照射技术对水模拟体系中吡虫啉和啶虫脒的降解作用,探讨了照射时间、紫外光强度、水模拟体系pH值和农药初始浓度等因素对降解效果的影响。结果表明,紫外光照射可有效降解水模拟体系中的吡虫啉和啶虫脒,且吡虫啉的降解效果优于啶虫脒。在本实验研究条件下,照射时间越长,紫外光强度越大,吡虫啉和啶虫脒的降解率越高;农药初始浓度越低,在相同照射时间下,吡虫啉和啶虫脒的降解率越高;中性和碱性的水模拟体系更利于啶虫脒的降解。采用紫外光强度为650μW/cm2的短波紫外光照射水体系30 min(pH 6,吡虫啉和啶虫脒初始浓度均为0.2μg/mL),吡虫啉和啶虫脒的降解率达到最大,分别为100%和46.30%。动力学研究表明,水模拟体系中吡虫啉和啶虫脒紫外光降解过程符合一级动力学模型(R2≥0.95)。     

高效液相色谱法检测几种蔬菜中啶虫脒农药残留

为提升啶虫脒农药残留的检测质效,增强食品安全,促进我国蔬菜生产的绿色化、生态化。相关检测机构、研究团队采用系列检测手段,对啶虫脒农药残留进行检测。以蔬菜啶虫脒农药残留检测作为研究对象,通过对高效液相色谱法检测原理、检测流程、注意事项的梳理与分析,打造成熟高效液相色谱检测机制。     

欧盟将提高进口我国茶叶农药残留标准

##正##8月25日,欧盟将正式提高对进口中国茶叶的农药残留标准,该法规所涉及的茶叶需要检测农药残留项目包括异丙隆、啶氧菌酯、嘧霉胺等。而其中最引人关注的,是我国茶农在茶叶种植中使用的啶虫脒限量再次被加严1倍。啶虫脒是茶园登记用药,因防虫效果好被广泛使用。在2013年啶虫脒的检测限量为0.1mg/kg,而今年该农药检测限量为0.05mg/kg。     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

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.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.     

Analysis on Economic Indicators from 62 Enterprises in Printing Machinery Industry in Q1 2014

Operation of printing machine industry was still unsatisfactory in the first quarter of 2014.Analysis on operation of printing machine industry.a.Market demand was not strong;sales of product undulated and declined.According to the statistics,the total industrial output value fell by 19.28% in the first quarter of 2014 than the average quarter value in 2013; industrial added value decreased by 4.16%; sales revenue dropped by 22.83%. h. Business operation of enterprises was in poor condition. c. R＆D of new products is an important transformation guarantee for enterprises. d. To take self explore new ways upgrading advantages,and explore new ways.