共振光散射法测定食品中锌含量

基于在pH8.5氯化铵-氨水缓冲溶液中,Zn2+与邻菲啰啉和亮黄发生反应,可使共振光散射显著增强,建立共振光散射法测定锌的新方法。考察测定影响因素,确定最佳测定条件为10mL比色管中加入pH8.5氯化铵-氨水缓冲溶液1.0mL、1.0×10-4mol/L邻菲啰啉溶液1.5mL和5.0×10-5mol/L亮黄溶液0.8mL,反应温度30℃,反应时间4min;最大共振光散射峰位于359.4nm,共振散射光强度增加值与Zn2+质量浓度在0～10μg/L范围内线性关系良好,方法的检出限为0.11μg/L,对样品进行测定,相对标准偏差为0.96%～1.71%(n＝5),平均回收率为98.00%～102.67%。本方法可用于测定香蕉、黄瓜和紫菜中锌含量,结果与原子吸收光谱法一致。     

共振光散射法测定坚果中镍含量

该文采用微波消解和巯基棉分离技术处理样品,对镍（Ⅱ）与1,10-菲啰啉（phen）和灿烂黄（brilliant yellow,BY）发生的配位显色反应进行研究,通过试验优化测定条件,建立一种新的共振光散射法（resonance light scattering,RLS）测定坚果中镍含量。结果表明,生成的配合物Ni（phen）2BY最大共振光散射峰位于535.9 nm,在此波长下测定共振光散射强度,共振光散射强度增大值与镍（Ⅱ）质量浓度在0～60 μg/L范围内线性关系良好,检出限为0.06 μg/L。新建方法用于测定坚果中镍含量,结果与原子吸收光谱法无显著性差异,相对标准偏差为1.75%～2.20%,加标回收率为98.6%～102.0%。     

灿烂黄褪色光度法测定调味品中铜含量

研究铜(Ⅱ)与1,10-菲啰啉和灿烂黄的络合反应,建立褪色光度法测定铜含量的新方法。通过试验优化酸度、1,10-菲啰啉用量、灿烂黄用量、反应温度和反应时间等测定条件。结果表明,最大褪色波长为474nm,表观摩尔吸光系数为7.92×104 L/mol·cm,铜(Ⅱ)浓度在0~0.6μg/mL范围内服从比尔定律,检出限为4.89μg/L。方法用于测定调味品中铜含量,结果与原子吸收光谱法一致,相对标准偏差为1.02%~1.36%(n=5),回收率为99.8%~102.1%。     

共振光散射法测定食用油中铁含量

采用微波消解对食用油进行前处理,根据铁(Ⅱ)在氨-氯化铵缓冲溶液中对邻菲啰啉和灿烂黄所产生的共振光散射具有显著增强作用,建立了共振光散射法测定食用油中铁含量的新方法.试验了酸度、邻菲哆啉用量、灿烂黄用量、反应温度和时间对测定的影响,确定了最佳反应条件,还考察了共存离子对测定的干扰情况.在优化的反应条件下,最大共振光散射峰位于360.9 nm,共振光散射增强量与铁(Ⅱ)质量浓度在0～0.25μg/mL范围内线性关系良好,相关系数为0.999 3,检出限为2.8 ng/mL.将该法用于食用油中微量铁的测定,相对标准偏差＜3％,回收率为97.3％～102.5％.该方法灵敏准确、简便快速、精密度高、高效环保,完全满足食用油中铁含量的检测要求.     

示波极谱法测定食品中人工合成色素赤藓红

本文采用示波极谱仪测定食品中人工合成色素赤藓红,赤藓红的0.25mol/L乙酸钠-1.40mol/L乙酸（pH3.6)缓冲液中,于-570mv处产生灵敏二阶导数波,其含量与波高成正比,最低检出浓度为0.019ug/mL,准确度和精密度符合定量分析的要求。     

高碘酸钾邻苯二酚紫催化光度法测定红枣中微量铁

以乙酸-乙酸钠(HAC-NAAC)缓冲溶液中微量铁催化高碘酸钾氧化邻苯二酚紫的褪色原理为基础建立了催化动力学光度法测定微量铁的新方法。反应体系为:0.01 mol/L高碘酸钾标准溶液1.0 mL,2.0×10~(-3)mol/L邻苯二酚紫0.5 mL,HAC-NAAC缓冲溶液(pH=4)5.0mL,反应温度35℃,反应时间15min。该方法的回收率为88%~94.7%,适合红枣中微量铁的检测。     

土霉素—邻菲啰啉快速测定饲料及粮食中微量铁(Ⅲ)的研究和应用

本文提出了在pH3～4.5,以土霉素-1,10邻菲啰啉为显色剂,分光光度法快速测定微量铁的新方法。其最大吸收波长510nm,摩尔吸光系数1.35×10~4L·mol~(-1)·cm~(-1),线性范围0.20μg/ml～10μg/ml,显色速度快,大量常见离子无干扰。可直接用于饲料和粮食中铁的测定。     

硒(Ⅳ)-碘化物-吖啶橙体系共振光散射法测定食盐中微量硒

基于在0.02 mol/L硫酸中,硒(Ⅳ)与过量的Ⅰ-反应生成Ⅰ3-,Ⅰ3-进一步与吖啶橙(AO)反应生成1∶1离子缔合物,导致体系共振光散射(RLS)强度明显增大,建立了共振光散射法测定硒的新方法.试验了酸度、试剂用量、表面活性剂、温度和时间的影响,确定了最佳测定条件.离子缔合物最大共振光散射峰位于552 nm.线性范围为0～48 μg/L.检出限(3σ/K)为0.109 μg/L.方法用于测定硒强化营养盐和健康平衡盐中微量硒,结果与荧光法一致,相对标准偏差分别为0.95%和1.07%(n=5),回收率为99.7%～100.9%.     

共振散射光谱法测定牛奶中的四环素

在1.0×10~(-5) mol/L的盐酸溶液中,四环素可与Co~(2+)发生络合反应形成螯合阳离子,该阳离子再与带负电的铝试剂通过静电引力作用形成三元离子缔合物,从而使反应体系的共振散射强度显著增强。在最优条件下,体系的共振散射强度增加值(△I)与四环素浓度在2.0×10~(-7 )mol/L～1.5×10~(-5) mol/L范围内呈良好的线性关系,回归方程为△I=1.247×10~7c+16.44(c为Tc的浓度,mol/L),检出限为4.81×10~(-8) mol/L,相关系数为0.997 1,据此建立一种测定四环素的新方法。将该方法用于检测牛奶样品中的四环素,加标回收率在99.28%～101.70%之间。     

双硫腙修饰丝网印刷电极同时检测茶汤中的Cu(II)和Pb(II)

在乙酸-乙酸钠缓冲溶液(0.1 mol/L、pH 5.0)中,利用双硫腙修饰丝网印刷电极阳极溶出伏安法分别于-0.18 V、-0.76 V阳极溶出峰同时测定重金属离子Cu2+和Pb2+。通过优化测定条件,得到最佳参数为:双硫腙修饰量3μg、pH 5.0、富集电位-1.1 V、富集时间210 s。在此条件下,Cu2+和Pb2+浓度分别在1.0×10-10-1.0×10-5mol/L、1.0×10-10-1.0×10-6mol/L范围内与峰电流呈良好的线性关系(RCu=0.9991,RPb=0.9934),检测限分别为0.35×10-10mol/L、0.41×10-10mol/L。该方法简单、快速、灵敏,可用于检测茶汤中的Cu2+和Pb2+。     

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