溴酸钾-甲基红-CTMAC增敏催化光度法测定食品中痕量亚硝酸根

基于稀磷酸介质中,氯化十六烷基三甲基铵对亚硝酸根催化溴酸钾氧化甲基红褪色反应的增敏作用,建立了测定痕量亚硝酸根的增敏催化动力学光度法。加入氯化十六烷基三甲基铵后,体系的灵敏度增大了4.3倍。研究了催化反应的动力学条件,测定了反应的表观速率常数(k=1.02×10-3/s)和表观活化能(Ea=42.76kJ/mol)。测定亚硝酸根的线性范围为5.0～300μg/L,检出限为0.59μg/L,方法的相对标准偏差优于2%,标准加入回收率为99%～101%。用于食品样品中亚硝酸根的测定,结果满意。     

涡旋辅助分散液液微萃取分光光度法测定饮用水中的亚硝酸根

目的建立涡旋辅助分散液液微萃取分光光度法检测饮用水中亚硝酸根的含量。方法在酸性条件下,亚硝酸根与对硝基苯胺和二苯胺反应生成红色偶氮化合物,通过测定红色偶氮化合物间接测定亚硝酸根的含量,以分光光度法检测,外标法定量。确定萃取剂种类,利用正交试验对萃取剂的用量、酸浓度和涡旋时间进行优化。结果在浓度10～200μg/L范围内线性关系良好(r2=0.9912),检出限为2.0μg/L,富集倍数为14。加标回收率为87.3%～106.3%,相对标准偏差0.8%～4.4%。结论该方法具有简单、快速、灵敏度高、准确性好,适用于饮用水中亚硝酸根的日常监测。     

亚甲基蓝催化光度法测定亚硝酸盐

在前人研究基础上建立利用亚甲基蓝作为指示物质的催化光度法,优化具体的反应条件,建立了亚硝酸根的催化光度测定法.方法检出限为0.0μg/L,线性范围为0.05～6.00μg/mL.可用于测定水、蔬菜、肉制品等不同食品中的亚硝酸根.结果与国标法相符,12次测定结果的RSD ≤3.0%.     

恒波长同步荧光猝灭法测定痕量亚硝酸根

在HCl介质中,Δλ=20nm,亚硝酸根对溴酸根氧化罗丹明B具有催化作用,使罗丹明B同步荧光发生猝灭,且猝灭程度与亚硝酸根浓度能形成线性关系,据此建立了恒波长同步荧光猝灭测定微量亚硝酸根的新方法。方法的检出限为1.3ng/m L,线性范围为2μg/L~52μg/L。该方法可用于火腿肠中亚硝酸根含量的测定能得到满意结果。     

罗丹明6G恒波长同步荧光猝灭法测定痕量亚硝酸根

建立了恒波长同步荧光猝灭测定微量亚硝酸根的新方法。研究表明:在HCl介质中,Δλ=25nm,亚硝酸根对溴酸根氧化罗丹明6G具有催化作用,使罗丹明6G的同步荧光发生猝灭,且猝灭程度与亚硝酸根量形成线性关系。方法的检出限为0.68μg/L,线性范围为2~36μg/L。该方法可用于火腿肠中亚硝酸根含量的测定,能得到满意结果。     

酒样中亚硝酸根的离子色谱测定法研究

建立了一种快捷、准确的离子色谱测定酒中亚硝酸根的方法。其检测线性范围为0.05～25.0 mg/L,检出限(μg/L,S/N=3)为17.5μg/L,样品加标回收率为90%～102%。样品检测结果比对了离子色谱-紫外检测器的检测结果,达到了理想效果。     

肉制品中亚硝酸盐的测定

基于在硫酸介质中,β-环糊精对亚硝酸根催化溴酸钾氧化二甲基黄的褪色反应具有增敏作用,建立了测定亚硝酸根的催化动力学光度法,测定亚硝酸盐的线性范围:0~20μg/L,加标回收率为96.20%~105.8%,6次测定的RSD小于4%。用于肉制品中亚硝酸盐的测定,结果令人满意。     

动力学光度法测定食品中痕量亚硝酸根

基于稀H3PO4介质中，痕量亚硝酸根对高碘酸钾氧化结晶紫的褪色反应有明显的催化作用，建立了痕量亚硝酸根的动力学光度测定法，方法检出限为0．06μg／L，线性范围为0～4．0μg／L。用于测定食品中的痕量亚硝酸根，结果与Griess法相符，6次测定结果的RSD≤5．0％。     

酸泡菜中亚硝酸根离子快速测定--格里斯光度法

拟订一个酸泡菜中亚硝酸根离子的测定方法。在盐酸介质中,亚硝酸根离子与对氨基苯磺酸偶氮化后,再与α-萘氨盐酸溶液偶联生成紫红色的偶氮化合物。该方法简便,快速,灵敏度高,选择性好,干扰少,方法检出限为1×10mg/L,测定范围为0～0.4mg/L。实验结果表明,该方法用于测定各种酸菜中亚硝酸根离子,其结果令人满意。     

酸白菜中亚硝酸根离子的测定

研究了酸白菜中亚硝酸根离子的一种检测方法。在盐酸介质中,亚硝酸根离子与对氨基苯磺唆重氮化后再与α-萘胺盐酸溶液偶联生成紫红色的偶氮化合物。该方法简便、快速、灵敏度高,选择性好、干扰少,方法检出限为10μg／mL,测定范围为10～280μg／mL。     

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