酶速测法检测茭白中农药残留的假阳性消除方法

目的建立一种能有效减小茭白中植物次生质对胆碱酯酶活性的影响的前处理方法。方法将样品经高温水浴热处理后酶速测法检测,通过比较水浴热处理前后酶抑制率的差异评价该方法的有效性。同时对18种具有代表性的机磷类农药或氨基甲酸酯类农药进行热稳定性实验和验证实验。结果实验结果表明能最有效地消除茭白基质中假阳性发生的最佳前处理条件是水浴温度90℃、热处理7 min。18种具有代表性的机磷类农药或氨基甲酸酯类农药热稳定性实验和验证实验结果表明在最佳实验条件下,大部分有机磷类和氨基甲酸酯类农药不发生受热分解,小部分农药(抗蚜威、甲基毒死蜱和对硫磷)易受热分解。结论该前处理方法对热稳定性强的农药能有效消除或减少茭白中假阳性的发生,但对少部分热稳定性差的农药并不一定能消除假阳性,甚至由于易受热分解,导致出现假阴性的检测结果。该方法简单、低成本,对于现场快速检测具有重要的意义。     

麦麸酯酶抑制法检测辛辣蔬菜假阳性消除的研究

利用酶抑制法可以快速检测蔬菜中的有机磷和氨基甲酸酯类农药残留,这两者能够抑制酯酶的活性,而辛辣蔬菜中含有影响酶活性的含硫化合物,容易导致检测结果出现假阳性。为了消除辛辣蔬菜造成的假阳性,以酶活性抑制率为指标,采用不同的加热方式、时间对4种辛辣蔬菜进行前处理。结果表明,对样品提取液使用水浴加热可起到消除假阳性的作用,其中香葱、洋葱、大蒜和青椒的最佳水浴加热温度分别为80、90、80、80℃,经过处理后的样品提取液对麦麸酯酶的抑制率分别由原来的37.06%、9.65%、17.02%、50.34%下降到12.69%、2.95%、5.79%、33.61%。除青椒外,该方法可在一定程度上消除或大大降低植物酯酶抑制法中假阳性的影响,且不会造成农药残留的损失,从而提高酶抑制法对辛辣蔬菜快速检测的准确性。     

NY/T448-2001标准方法的验证分析

本文验证比较了NY／T448－2001蔬菜上有机磷和氨基甲酸酸酯类农药残毒快速检测方法测定蔬菜中农药残留与气相色谱法测定农药残留结果的比较，结果表明：速测法用于含硫化物高的蔬菜易受干扰，检测中易出现假阳性结果。     

速测卡法快速检测蔬菜中有机磷和氨基甲酸酯类农药残留

目的对数字农药残留速测卡速检蔬菜中有机磷和氨基甲酸酯类农药残留方法的可靠性及实用性进行评价。方法采用改良后的速测卡对有机磷及氨基甲酸酯类农药的最低检出限进行试验,以及检测蔬菜样品中农药残留情况,并与标准方法进行对比;并对不同生产批号的产品进行重复性试验。结果速测卡对有机磷和氨基甲酸酯类农药的最低检出限在0.01~3.0 mg/kg;对敌敌畏可达到0.01 mg/kg;对乙酰甲胺磷灵敏度较低,为3.0 mg/kg。检测样品时,速测卡与标准方法阴性符合率为95.2%,阳性符合率为94.1%。5个生产批号的速测卡检测结果一致,批次间重复性较好。结论速测卡法具有快速、准确、方便、灵敏等特点,适用于基层对蔬菜中有机磷及氨基甲酸酯类农药残留进行定性分析。     

韭菜中杀菌剂类农药残留检测技术研究进展

韭菜是药食同源植物,病害较多,通常使用化学杀菌剂进行防治。但农药的使用种类、次数、剂量不科学,杀菌剂残留已成为韭菜的主要外源污染物之一。为探明韭菜农药残留风险状况,综述近年来发表的相关文献,对韭菜常见病害的农药使用种类、检测技术进行整理和分析。样品前处理及检测是样品农药残留分析的2个主要部分,韭菜中杀菌剂前处理技术主要包括固相萃取、液相萃取、固相微萃取、QuEChERS方法及凝胶渗透色谱。检测方法以气相色谱(GC)、液相色谱(LC)或两者与质谱(MS)联用为主。韭菜质量安全是保障食品安全的重要前提,高通量的农药残留检测方法亟须建立并实施。     

快速检测卡和酶联免疫试剂盒检测动物性食品中3种β-兴奋剂

目的评价快速检测卡和酶联免疫试剂盒检测动物性食品中3种β-兴奋剂的准确性。方法分别采用快速检测卡和酶联免疫吸附法检测动物性食品中盐酸克伦特罗(CLB)、莱克多巴胺(RAC)和沙丁胺醇(SAL)3种β-兴奋剂残留,并与液相色谱-串联质谱法(LC-MS/MS)进行比较评价。结果盐酸克伦特罗速测卡和克伦特罗-莱克多巴胺-沙丁胺醇三联速测卡的检测结果与LC-MS/MS的符合率分别为83.3%和87.5%(CLB)、12.5%(RAC)、100%(SAL),CLB、RAC、SAL和β-兴奋剂ELISA试剂盒的检测结果与液相色谱-串联质谱法的符合率分别为94%、94%、76.2%和75%。结论试剂盒的准确度相对较高,但部分试剂盒的假阳性和假阴性情况明显。速测卡检测限较高,准确度较差,不满足一般检测要求。     

采用乙酸-微波处理优化韭菜中有机磷农药残留检测方法的研究

摘要：目的 韭菜中硫化物成分对有机磷农药残留的检测造成干扰,研究利用乙酸-微波消除韭菜基质对有机磷农药残留检测干扰。方法 通过对韭菜基质与有机磷农药的检测,分析韭菜基质对有机磷农药残留检测干扰;采用10%乙酸和中高火微波,分别处理10 s、20 s、30 s、40 s、50 s、60 s,分析各处理的韭菜本底变化;韭菜样品中添加0.08 mg/kg水平的有机磷农药, 采用10%乙酸和中高火微波,分别处理50 s、60 s,测定各处理的有机磷农药回收率及其相对标准偏差,分析乙酸-微波处理对检测结果准确性的影响。结果 确定了韭菜本底峰12.145对甲拌磷、峰16.119对毒死蜱、峰17.169对甲拌磷砜造成干扰;韭菜的本底干扰峰随处理时间的延长其峰面积及峰高呈下降趋势,当处理时间达到50 s以上时,韭菜本底峰从11个降为4个,且三种干扰峰都未检测到;处理时间50 s时,各有机磷农药的加标回收率为78.4%～104.8%,相对标准偏差为7.4%～13.1%。 结论 发现乙酸-微波处理50s,消除韭菜基质对有机磷农药残留检测干扰效果明显,从而有效提高了有机磷农药残留检测结果的准确性,获得有机磷农药的加标回收率和精密度符合国家标准规定,且达到最佳效果。     

韭菜中农药残留状况调查与分析

目的了解韭菜中农药残留状况。方法抽取北京市批发市场和蔬菜生产基地销售的韭菜样品174个,检测其中的甲胺磷、氧乐果等58项农药残留,并依据GB 2763-2019《食品中农药最大残留限量》进行判定。结果市场销售韭菜农药残留的检出率明显高于生产基地, 7～8月份的韭菜农药残留检出率相对较低,检出率排在前5位的农药依次为腐霉利20.6%,多菌灵11.2%,氯氰菊酯8.62%,毒死蜱和嘧霉胺7.47%,其中腐霉利是引起韭菜农药残留超标的主要原因之一,检出2种以上农药的韭菜占检出样本总数的64.3%。结论韭菜中检出的农药种类较多,属于高风险的蔬菜品种之一,韭菜质量安全状况还需进一步加强,需要引起有关部门的重视。     

市售韭菜中农药残留及重金属污染状况

目的：科学管理湖南省韭菜食品安全。方法：对湖南地区690份韭菜样本中24项农药和5项重金属进行检测。结果：① 农药残留检出率为23.19%,检出率排名前3的农药分别为多菌灵、腐霉利和氯氰菊酯;农药残留的超标率为5.80%,其中腐霉利超标率最高,达2.61%。② 重金属元素检出率为77.68%,超标率为3.62%,其中检出率和超标率最高的重金属元素均为镉。结论：韭菜农药残留量较高,且重金属元素检出率远高于其农药残留检出率,其中,农药腐霉利和重金属镉为韭菜的主要超标项目,建议加强韭菜中农药残留及重金属污染的持续监测。     

基于酶抑制法的农药残留快速检测仪器现状及评价

为了确保果蔬类农产品的食用安全, 对蔬菜瓜果进行农药残留的检测十分重要。本文通过对我国农药残留快速检测仪器的发展现状和评价方法的讨论, 分析了基于酶抑制法的农残速测仪器现存的主要问题, 并提出进行农残速测仪器评价工作的必要性。     

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