高效液相色谱法同时测定饲料添加剂中6种有机酸含量

建立高效液相色谱法同时分离测定饲料添加剂中的甲酸、乳酸、乙酸、柠檬酸、丙酸、苯甲酸含量的方法。样品用盐酸溶液(0.1%)∶乙腈(1∶1)超声提取,应用ZORBAX SB-C18色谱柱,以乙腈和盐酸溶液(0.1%)为流动相进行梯度洗脱,紫外检测器在210 nm处进行检测,外标法定量。结果表明,6种有机酸线性关系良好,相关系数均为0.999 9,回收率96.5%~103.2%,变异系数0.94%~4.15%,甲酸、乳酸、乙酸、柠檬酸、丙酸、苯甲酸检出限分别为检出限分别为0.1、1.0、1.0、0.5、0.5、0.02μg/m L。该方法操作简便、灵敏度高、重现性好,适用于饲料添加剂中6种有机酸含量的测定。     

高效液相色谱法测定传统发酵乳中的有机酸组成

利用高效液相色谱(HPLC)法研究了传统发酵乳中的7种有机酸的分离测定条件,同时对青海省传统发酵乳酸牦牛奶、酸山羊奶和酸马奶等40个样品的乳酸、乙酸和柠檬酸含量进行了测定。结果表明,选择浓度为0.010 mol/L磷酸—磷酸二氢钠(pH=2.0)和甲醇(体积比为98︰2)做流动相,流速为0.5 mL/min,紫外检测波长为210 nm时可以较好地分离测定发酵乳中的乳酸、乙酸和柠檬酸。该方法不仅相对标准偏差小(0.35%～1.23%),回收率高(95.4%～103.8%),线性相关系数高(乳酸r>0.99994,醋酸r>0.99997,柠檬酸r>0.99999),而且具有较高的准确度和精确度;通过发酵乳样品的有机酸含量测定发现,发酵乳中除主要含有乳酸外还有微量的乙酸、柠檬酸和痕量的甲酸、苹果酸、琥珀酸及丙酸。3种家畜奶发酵乳中各种有机酸含量有较大差别。     

LC-MS法测定四种果蔬中的有机酸

采用超高效液相色谱-质谱联用法对橘子、树莓、甘蓝和菠菜中的6种有机酸(酒石酸、苹果酸、柠檬酸、琥珀酸、富马酸和马来酸)进行检测。选用ACQUITY UPLC~;HSST3色谱柱进行分离,0.1%甲酸/乙腈溶液-0.1%甲酸/水体系作为流动相进行梯度洗脱,流速为0.25 m L/min,选择ESI-多反应监测模式进行扫描。6种有机酸的平均回收率为77.9%~104.0%,相对标准偏差RSD值为2.0%~12.4%,相关系数R~20.998 9,该方法的最低检出限的分别为0.02 mg/kg和0.05 mg/kg,最低定量限分别为0.1 mg/L和0.25 mg/L。准确、高效地测出了四种果蔬中有机酸的含量。     

离子交换色谱法测定食醋中有机酸

采用离子交换色谱法分离测定了食醋中有机酸,检测的有机酸有乳酸、乙酸、丙酸、甲酸、丙酮酸、琥珀酸、草酸、柠檬酸,样品加标回收率为81%～110%,变异系数均在5%以内,方法简便、准确、快速.     

红茶菌发酵液的有机酸组成分析

首先对红茶菌发酵过程中的p H、糖度、总糖、总酸及总酚含量等随发酵时间的变化进行研究,又采用离子排斥液相色谱法对发酵液中的有机酸进行分析。以高交联度磺化苯乙烯-二乙烯基苯共聚物多孔微球作为固定相的Aminex HPX-87H离子色谱柱作为分析柱,利用二极管阵列检测器对8种有机酸(柠檬酸、苹果酸、琥珀酸、乙酸、丙酸、丁酸、草酸、乳酸)进行了较成功的分离,并应用于红茶菌发酵液的有机酸分析。通过色谱条件优化,选定了55℃为柱温和10 mmol/L的H2SO4作为流动相。利用上述方法进行测定,能够有效地对红茶菌发酵液中的6种有机酸(柠檬酸、苹果酸、琥珀酸、乙酸、丙酸和丁酸)进行提取、分离和测定,回收率为97.1%~102.9%,RSD为0.1%~6.5%。     

基于RP-HPLC法测定水果及其果酒中有机酸含量

采用反相高效液相色谱法同时测定菠萝皮渣、火龙果汁及其发酵酒中草酸、柠檬酸、酒石酸、苹果酸、丙酮酸、琥珀酸、乳酸和乙酸8种有机酸组成和含量;色谱条件:色谱柱BP-OA,流动相A(1%H_3PO_4)和B(超纯水),柱温30℃,流速0.5 mL/min,紫外检测器(210 nm)。结果表明,各有机酸分离度在1.34以上,检出限为0.03~0.49μg/mL,RSD为0.9%~3.1%,平均回收率在93.4%~108.6%之间(S/N=3)。柠檬酸和苹果酸在菠萝皮渣中含量最高,而火龙果汁中苹果酸含量最高。其果酒中柠檬酸、苹果酸和草酸含量降低,但琥珀酸、丙酮酸、乙酸、酒石酸和乳酸含量升高。菠萝酒中柠檬酸、苹果酸和草酸含量分别降低96.04%,71.84%和77.20%,琥珀酸含量升高72.13%。火龙果酒与果汁相比苹果酸含量降低91.41%,草酸含量降低52.02%,而乙酸含量升高88.32%。     

离子色谱法测定山楂和乌梅中的有机酸

建立了抑制电导检测-离子排斥色谱法同时测定6种有机酸(草酸、柠檬酸、苹果酸、琥珀酸、乙酸、丙酸)的方法,并用于检测山楂和乌梅中的有机酸含量。以METROSEP Organic Acids(250mm×7.8mm)为分离柱,以10mmol/L LiCl溶液和超纯水为抑制器再生液,淋洗液为0.5mmol/L H2SO4溶液+10%丙酮,流速0.6mL/min。6种有机酸在17min内能够全部出峰,线性方程的相关系数(R)在0.9988～0.9996之间,检出限在0.05～1.20mg/L之间,样品加标回收率在90.54%～112.86%之间。在山楂和乌梅样品中检测出了柠檬酸和苹果酸,其中柠檬酸含量较高。该方法适用于快速测定山楂和乌梅中的有机酸含量。     

色谱法比较分析不同品种酱油关键指标的差异

为了探讨酿造酱油与配制酱油关键指标差异的检测方法。样品经简单前处理后,采用液相色谱法测定样品中的甲酸、乙酸、乳酸、酒石酸、柠檬酸、琥珀酸、丙酮酸、乙酰丙酸的含量,各有机酸分离良好。在一定线性范围内相关系数均大于0.997 6,相对标准偏差(RSD)为0.68%~5.13%,检测回收率为90.6%~98.2%,最低检出限为0.000 1 mg/m L~0.0005 mg/m L。结果表明,不同生产工艺的酱油,其有机酸含量存在较大的差异。方法操作简单,结果准确,对酱油能进行很好的分类。     

QuEChERS EMR-Lipid-LC/MS/MS测定8种β-受体激动剂

建立以QuEChERSEMR-Lipid为前处理测定动物源性食品中8种β-受体激动剂的LC-MS/MS方法。样品经粉碎混匀后加入pH为5.2乙酸-乙酸铵溶液,以β-盐酸葡萄糖醛酸苷酶/芳基硫酸酯酶酶解,酶解液经QuEChERSEMR-Lipid净化后,取乙腈层与0.1%的甲酸水溶液混合上LC-MS/MS进行分析。8种β-受体激动剂在测定浓度范围内线性关系良好,各组分相关系数R~20.998,加标回收率范围79.1%~94.8%,方法精密度范围5.4%~9.4%,测定各组分β-受体激动剂检出限范围0.2μg/kg~0.4μg/kg,定量限范围0.5μg/kg~1.0μg/kg。     

青梅有机酸谱特性分析及其应用研究

为了更好地表征和鉴别青梅及其加工产品的质量,建立了HPLC法同时分析样品中草酸、酒石酸、苹果酸、乳酸、乙酸、柠檬酸、琥珀酸及熊果酸8种有机酸组成及含量。采用的色谱柱为Zorbax SB-Aq C18(4.6×250 mm,5μm),以甲醇与0.01 mol/L且pH为2.65的KH2PO4溶液(3:97)为流动相,流速为1.0 mL/min,柱温25℃,选取210 nm与215 nm进行双波长检测,有机酸的回收率为97.18%~111.57%,相对标准偏差为0.53%~4.67%,检出限为0.05~6.33μg/mL。青梅中主要有机酸为柠檬酸,其次是苹果酸和草酸,还含少量的酒石酸、乳酸、乙酸和琥珀酸,多种有机酸共同构成青梅特征有机酸谱。利用建立的青梅有机酸谱HPLC分析方法,分析不同青梅加工产品的有机酸谱,发现青梅在加工成不同产品过程中尽管总有机酸含量变化很大,但特征组成谱稳定,一些乌梅提取物存在掺假现象,表明青梅有机酸谱可以用于表征青梅加工产品的质量。     

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