茶氨酸的HPLC快速检测

建立了未衍生化高效液相色谱法(HPLC)快速检测茶叶及绿茶提取物中茶氨酸含量的方法。采用Zorbax SB-AQ色谱柱(250mm×4.6mm,5μm),乙腈:0.1%磷酸溶液=5:95(体积比)为流动相,流速1mL/m in,进样量10μL,柱温25℃,检测波长196nm。结果表明茶氨酸在0.02mg/mL 0.20 mg/mL浓度范围内线性关系良好,相关系数r=0.9998,加样回收率为98.59%(n=5)。本方法检测快速,定量准确,可用于茶叶及绿茶提取物中茶氨酸含量的测定。     

柱前衍生法测定茶叶中L-茶氨酸的含量

本文研究了柱前衍生测定茶叶中L-茶氨酸含量的方法。茶叶中的L-茶氨酸用热水提取后,经2,4-二硝基氟苯衍生后上高效液相色谱法测定。色谱条件为:色谱柱(Kromasil C18柱4.6 mm×250 mm,5μm);流动相:乙腈︰磷酸盐溶液(pH=6.5)=15︰85梯度洗脱;检测波长:360 nm;流速:1.0 mL/min;柱温:35℃;进样:5μL。本方法检出限4 mg/kg,在1.0~50.0μg/mL呈现良好的线性关系(r=0.999 9),衍生后的样品室温25℃放置6天内稳定,重现性试验相对标准偏差0.16%(n=6),回收率为96.4%~102.2%。本高效液相色谱法可以准确地测定茶叶中L-茶氨酸的含量。     

亲水高效液相色谱法测定饮料中的维生素C含量

目的:建立一种简便、快速、灵敏的测定饮料中维生素C含量的方法。方法:采用氨基丙基色谱柱Agilent Zorbax carbohydrate(250mm×4.6mm,5μm),流动相为0.02mol/L磷酸二氢钾+甲醇=95+5,流速1.0m L/min,检测波长:249nm,柱温:25℃,测定饮料中的维生素C含量。该方法检测线性范围为1.46~146μg/m L,样品检出限为0.08μg/m L,加样回收率为99.34%。结论:该方法利用亲水色谱的原理,使用氨基丙基色谱柱分析饮料中维生素C的含量,克服了传统液相色谱方法维生素C在C18柱上保留不足的问题,能够实现样品中杂质与目标峰的有效分离,且前处理简单,测定准确、简便、快速,是一种更为实用快速的维生素C的液相色谱分析方法。     

HPLC法快速测定婴幼儿配方奶粉中维生素B_1

建立了快速测定婴幼儿配方奶粉中维生素B_1的高效液相色谱法。样品经水提取,饱和乙酸铅溶液沉淀蛋白,碱性铁氰化钾衍生,采用C_(18)色谱柱分离,以乙酸钠-甲醇(65∶35,V/V)为流动相,荧光检测器检测。该方法检出限为0.2 mg/kg,线性范围为0.01~1.0μg/m L,样品加标回收率在86.0%~88.8%之间。该方法样品前处理简便快速、测定结果符合定性定量要求,适用于婴幼儿配方奶粉中维生素B_1的测定。     

高效液相色谱法测定绿茶饮料中咖啡因的含量

利用高效液相色谱法快速测定了绿茶饮料中咖啡因的含量。色谱柱为Agilent TC-C18(2)柱(250mm×4.6mm(5μm)),流动相为甲醇∶水=5∶5(体积比),流量0.8m L/min,检测波长286nm,进样量10μL,咖啡因在浓度为10~50μg/m L范围内,峰面积Y与浓度X之间有良好的线性关系。     

亚麻油中TBHQ、BHA和BHT的同时快速检测

建立了高效液相色谱法同时快速测定亚麻油中特丁基对苯二酚(TBHQ)、叔丁基茴香醚(BHA)和2,6-二叔丁基对甲酚(BHT)3种抗氧化剂的方法。采用甲醇(5 m L+5 m L)直接提取亚麻油中的TBHQ、BHA和BHT,C18柱(4.6 mm×250 mm×5μm)进行分离,紫外检测器检测。流动相用甲醇和1%乙酸梯度洗脱,流速为1.0 m L/min,进样量为10μL,检测波长为280 nm。3种抗氧化剂的检出限:TBHQ为0.04μg/m L,BHA为0.01μg/m L,BHT为0.02μg/m L,回收率为91.2%~103.6%;相对标准偏差在2.5%~6.8%之间。     

高效液相法测定爬山虎红色素中原花青素含量

采用高效液相色谱法对爬山虎红色素中原花青素的含量进行了测定. 色谱柱:C18柱(日本岛津5μm;150 mm×4.6mm),柱温:25℃,流动相:V(甲醇):VU(水)=90:10,检测波长:280 nm,进样量:20 μL,流速:1 ml/min.结果表明在0.50～7.5μg/mL范围内具有良好的线性关系,回收率为99.96%,相对标准偏差为1.0%,原花青素的平均含量为6.8 μg/mL.结论是本方法简便、快速、准确、可靠,可为爬山虎叶子提取物红色素中原花青素的含量测定的方法.     

高效液相色谱法测定婴幼儿奶粉中的叶黄素

建立一种快速的高效液相色谱测定婴幼儿奶粉中叶黄素的方法。选用含0.1%BHT的甲醇溶液作为提取液,甲醇-水(95︰5, V/V)作为流动相,用C18柱在445 nm检测波长下等度分离;该方法在0.02～1.0μg/m L浓度范围内线性关系良好,检出限为0.05 mg/kg,精密度试验的相对标准偏差低于5%, 10 h内样品溶液中叶黄素峰面积的相对标准偏差为0.36%, 20, 100和250μg/100 g 3个质量水平的加标回收率在90.5%～94.2%之间。该方法操作简便、灵敏度好、准确性高,适用于婴幼儿奶粉中叶黄素的测定。     

HPLC法分析测定“黑美人”马铃薯中原花青素

建立高效液相色谱法分离测定"黑美人"马铃薯中原花青素含量的分析方法。实验采用C18柱(Phenomenex5μm;250 mm×4.6 mm);V(甲醇)∶V(0.5%冰醋酸水溶液)=30∶70为流动相;柱温:25℃;流速:1 m L/min;检测波长:287 nm。结果表明:原花青素在80μg/m L~200μg/m L浓度范围内有良好的线性关系,相关系数R=0.995 7,方法的精密度RSD为2.86%,平均回收率为100.1%,原花青素的平均含量为51.805 mg/g。本方法简便、快速、准确、可靠,可用于"黑美人"马铃薯中原花青素的含量的测定。     

正相色谱法测定大豆磷脂中的磷脂酰胆碱

目的建立正相色谱法测定大豆磷脂中磷脂酰胆碱含量,用于大豆磷脂类保健食品生产过程中该物质含量的测定和质量控制。方法采用硅胶柱(4.6 mm×250 mm,5.0μm)进行分离;色谱条件为流动相:异丙醇:正己烷:蒸馏水=70:16:14(V:V:V),等度洗脱,流速:1.0 m L/min;柱温:40℃;进样量:10μL;检测波长:205nm;并进行方法学验证,考察方法检测限、精密度、回收率等指标。结果磷脂酰胆碱峰面积与其浓度呈良好的线性关系,线性范围为0.1~0.8 mg/m L(r=0.9999),检出浓度0.04μg/m L,检出限为20μg/g,定量限为66.666μg/g,精密度(RSD)为0.6%,平均回收率99.37%(n=9)。结论本文建立的方法灵敏度高,重复性好,且具有很好的专属性,能够应用于大豆磷脂类保健食品中磷脂酰胆碱含量的检测。     

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.     

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.     

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