鱼体中两种挥发性有机残留物的提取与检测

目的 研究水蒸汽蒸馏方法提取鱼体中挥发酚和硝基苯的效果, 并研究鱼体中挥发酚和硝基苯残留量的测定方法。方法 用自制水蒸汽发生器蒸馏提取挥发酚和硝基苯, 并测定两种物质含量。结果 水蒸汽发生器蒸馏法泡沫产生少, 蒸馏过程稳定、容易控制, 不存在暴沸现象。鱼体中挥发酚测定平均回收率在85.5%以上, 硝基苯测定平均回收率为96.83%。硝基苯出峰时间为10.051 min, 分离度高, 检测时间短、消耗有机溶剂量少、试验简便, 完全能够满足检测分析的需要。 结论 水蒸汽蒸馏提取法效果好, 方法实用, 便于操作, 适用于处理后样品的分析测定, 已应用于鱼体中挥发酚和硝基苯残留量的测定。     

果蔬中甲醛提取方法的优选研究

对比了超声波提取法、振荡提取法、水蒸气蒸馏法和直接蒸馏法4种方法提取果蔬中甲醛的效果,通过乙酰丙酮分光光度法测定甲醛含量,得出果蔬中甲醛的较适宜提取方法。试验结果表明,甲醛较适宜的提取方法为超声波提取法,超声波提取法的最佳提取条件为超声波功率80 W,提取时间30 min,提取温度60℃,超声波提取1次,甲醛提取剂蒸馏水用量为每10 g样品中加入40~60 m L(料液比为1︰4~1︰6(g/m L))为宜。样品中甲醛的平均回收率为77.6~91.7%,相对标准偏差为3.8%~5.6%。相比水蒸气蒸馏法、直接蒸馏法和振荡提取法三种方法操作更为简便,提取过程中不会造成样品中甲醛含量发生变化,稳定性好。     

超高效液相色谱法测定皮革中甲醛含量

建立了采用超高效液相色谱测定皮革中甲醛含量的方法。样品经简单的前处理和衍生化反应后,通过Agilent Zorbax Eclipse XDB C18快速高通量色谱柱分离,一次进样分析仅需1min。在11.2～1120ng/mL范围内线性良好;相对标准偏差为0.93%。方法简便、快捷且准确,适用于皮革中甲醛含量的测定。     

直接蒸馏滴定AHMT法联合测定食品中的甲醛次硫酸氢钠

利用直接蒸馏滴定 AHMT法联合测定食品中的甲醛次硫酸氢钠。综合考虑了甲醛含量及SO2 /HCHO含量的比值 ,以判定食品中的甲醛次硫酸氢钠 ,各种样品以甲醛定量的加标回收率为 98 0 %～ 1 0 7 2 % ,相对标准偏差 (RSD)为 2 7%～ 4 1 %。此方法适用于各种食品中的甲醛次硫酸氢钠含量的测定。     

香菇中不同形态甲醛的测定与分析

香菇中同时存在游离态甲醛和结合态甲醛,建立一种可以一次性快速测定这两种形态甲醛含量的方法。根据香菇中两种形态的甲醛析出条件,实验设计了2个步骤:第一步,先通过蒸馏提取香菇中游离态甲醛;第二步,加酸后再次蒸馏,提取香菇中结合态甲醛。实验设定条件为:蒸馏时间为4 min,加10%磷酸40 mL,水浴温度为60℃,水浴时间为60 min。结论为,当甲醛浓度为0.0～10.0 mg/L时,标准曲线线性关系良好,相关系数r为0.9995,游离态甲醛检测的加标回收率为87.8%～105.9%,相对标准偏差(RSD)在3.5%～7.0%;结合态甲醛检测的加标回收率为89.5%～105.8%,相对标准偏差(RSD)在2.5%～6.7%。香菇中结合态甲醛含量占总甲醛的62.6%～71.8%,游离态甲醛和结合态甲醛在伞部的含量均高于柄部的含量。全自动定氮仪可以一次性处理香菇中不同形态的甲醛,与高效液相色谱联用,能够自动、快速、高效地完成香菇中甲醛形态的检测与分析。     

微波辅助水蒸汽蒸馏提取沙姜挥发油的研究

采用微波辅助水蒸汽蒸馏方法和传统水蒸汽蒸馏方法提取沙姜挥发油,用色谱-质谱联用分析鉴定,并用GC-MS总离子流色谱峰的峰面积归一化法对挥发油成分进行定量分析。实验结果表明,微波辅助水蒸汽蒸馏方法与传统水蒸汽蒸馏所得的挥发油成分基本相同,但微波辅助水蒸汽蒸馏的挥发油收率(2.55%)高于水蒸汽蒸馏挥发油的收率(2.13%)。微波辅助水蒸汽蒸馏方法是一种真正意义上的无污染、快速,且具有高收率的提取鲜活香料植物挥发油的萃取新技术。     

两种方法提取太行山地区花椒中挥发性化学成分的气相色谱-质谱分析

采用同时蒸馏萃取法和普通水蒸汽蒸馏萃取法,对产自太行山地区的花椒中的挥发油进行提取,测得花椒挥发油含量分别为12.5%、8.9%;并用汽相色谱-质谱联用技术进行分析鉴定,结合计算机质谱图库检索技术对分离的化合物进行结构分析,分别鉴定出45种(同时蒸馏萃取法)和26种(普通水蒸汽蒸馏萃取法)化学组分,分别占总挥发性物质总含量的94.68%和93.98%。应用峰面积归一化法确定了各成分的相对含量。结果表明:同时蒸馏萃取法提取的挥发油中主要含有苎烯(24.75%)、桉叶油素(8.91%)、β-蒎烯(7.81%)等,普通水蒸汽蒸馏萃取法提取的挥发油中主要含有桉叶油素(41.19%)、(+)-α-松油醇(12.25%)等。     

柱前衍生高效液相色谱法测定5种常见食用菌中的甲醛含量

目的建立柱前衍生-高效液相色谱法测定5种常见食用菌中甲醛含量。方法将干制与新鲜食用菌用超纯水浸泡,浸泡液经2,4-硝基苯肼(DNPH)衍生后,采用高效液相色谱法检测;色谱柱:C18(250mm×4.6mm,5μm),流动相:乙腈-水(70:30, V:V);流速为1.0 mL/min;检测波长352 nm;柱温40℃。外标法定量测定食用菌中甲醛含量。结果柱前衍生法对甲醛浓度在10.70～214.00μg/L范围内与其衍生物峰面积呈良好的线性关系,线性回归系数(r~2)为0.9964,方法的检出限为4.20μg/kg(S/N=3)。加标回收率为78.27%～114.26%,精密度1.55%～9.22%(n=6)。5种食用菌样品仅香菇样品检出甲醛。新鲜香菇甲醛含量超标,干制后香菇甲醛含量降低,低至国家标准含量以下。结论本研究的方法简便、快速、准确、稳定,可用于测定食用菌中甲醛含量。     

水产品中甲醛HPLC测定的前处理方法探讨

为了探讨前处理方法对水产品甲醛检测的影响,本文比较了三氯乙酸结合超声提取法(超声+TCA法)、三氯乙酸提取法(TCA法)、蒸馏水提取法、水蒸气蒸馏法四种前处理方法的高效液相色谱法(HPLC)测定甲醛。结果显示,水蒸气蒸馏和三氯乙酸超声提取平均回收率分别为109.06%和103.62%,而蒸馏水提取的回收率低于40%。经优化后的三氯乙酸超声提取条件优化为超声时间25min,10%TCA加入量10mL。因此,三氯乙酸超声提取具有稳定性较好,操作简便,与水蒸气蒸馏法前处理效果相当,是一种适合用于大多数鲜活和冷冻水产品甲醛含量检测的前处理方法。     

食品包装材料中甲醛的高效液相色谱分析

建立了采用高效液相色谱测定食品包装材料中甲醛含量的方法。样品经前处理和衍生化反应后,通过高效液相色谱仪进行快速分离,在1.46~571μg/L范围内线性良好,食品包装材料的回收率为92.1%~96.6%。该方法简便、快速、准确性高、重现性好,适用于食品包装材料中甲醛含量的测定。     

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