废水中S2-含量的间接电化学测定

在弱酸性(0.2mol/L醋酸-醋酸钠缓冲溶液,pH4.50)介质中,Cu2+与废水中的S2-发生完全定量化学反应,过量的Cu2+用方波伏安法检出,从而实现工业废水中S2-的间接测定.在上述实验介质条件下,Cu2+在汞膜电极上还原而呈现灵敏的方法伏安峰,其峰电位为-0.12v,检测下限达2.0×10-6mol/L,并且在很大的范围内有着极好的灵敏度,结果准确,不受其它干扰离子的影响.     

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+。     

表面活性剂增敏差分脉冲阳极溶出伏安法测定食品中痕量铅

在0.1mol/L NaNO_3和适量十六烷基三甲基溴化铵(CTAB)介质中,采用玻碳汞膜电极作为工作电极,差分脉冲阳极溶出伏安法测定金属Pb的增敏效果可达10倍左右,其溶出峰为-0.47V(V.S.Ag/AgCl 1mol/L KCl),线性范围为0～100ppb,其准确度和回收率分别在4.6%～9.9%和92%～114%之间。     

微分电位溶出法测定水中铊

经过试验,选择在 0. 1mol/L的醋酸盐和 0. 009mol/L的EDTA介质中,以微分电位溶出法测定水中微量铊,方法简单,灵敏,结果准确,在 -1. 10V(Vs·SCE)下电解 100S,可检出2. 0μg/L的铊,铊浓度在 5. 0~100. 0μg/L范围内,溶出峰高与浓度成良好线性关系,该法的精密度RSD为 0. 9% ~7. 1%,回收率为 97. 0% ~101. 3%。     

线扫阳极溶出伏安法测定茶汤中的Pb、Cu

采用线扫阳极溶出伏安法测定茶叶中的Pb、Cu含量 ,在 0 .3mol/L盐酸底液中 ,Pb、Cu的加标回收率P %分别为93.3%～ 1 0 6 .8%、93.9%～ 1 0 5 .4 % ,测定精密度RSD %分别为 0 .39%～ 2 .1 0 %、0 .33%～ 3.2 0 % ,Pb、Cu的线性范围为 0 .1 0～ 0 .70mg/L。     

聚γ-氨基丁酸修饰电极测定食品中的莱克多巴胺

采用循环伏安法制备聚γ-氨基丁酸修饰电极,并对聚合条件进行了优化,以建立测定食品中莱克多巴胺含量的电化学分析方法。用循环伏安或差分脉冲法探讨了莱克多巴胺在聚γ-氨基丁酸修饰电极上的电化学行为。结果表明,莱克多巴胺的氧化峰电流与其浓度在6. 0×10-8～1. 0×10-5mol/L范围线性关系良好,R2=0. 998 8。检出限为8. 0×10-9mol/L。回收率为98. 0%～102%,RSD为2. 3%～3. 1%。循环伏安法简单、快速、灵敏,为莱克多巴胺的测定提供了新方法,为食品控制提供了依据。     

1-(4-偶氮苯基苯)-3-丙基-三氮烯键合硅胶修饰碳糊电极溶出伏安法测定饲料中镉的研究

以1 - (4 - 偶氮苯基苯) - 3 - 丙基 - 三氮烯键合硅胶(ABPT - SG)为修饰剂,液体石蜡为粘合剂,制备了ABPT - SG修饰碳糊电极.在pH8.0、浓度为0.2 mol/L的氨性缓冲底液中,于-1.2 V(Vs.SCE,下同)的电位下富集,将Cd2+以Cd - ABPT - SG络合物的形式吸附在电极上,用阳极溶出伏安法测定.在-0.60 V处Cd有一灵敏的阳极溶出峰,峰电流与Cd2+的浓度在5.0×10-6～1.0×10-3 mol/L范围内呈良好的线性关系,测定饲料中的镉,检出限为1.0×10-8 mol/L.     

微分脉冲伏安法测定加碘盐中碘酸根离子

报道了运用微分脉冲伏安法测定食盐中碘酸根含量的方法。在1.0mol/LNaCl,pH=12的介质中,当脉冲振幅为70mV,脉冲周期为0.2s时,碘酸根离子在微分脉冲伏安图上出现一个灵敏的微分脉冲伏安峰,峰电位为-1.30V(vs.Ag/AgCl),峰电流与碘酸根离子浓度在2.0×10-7～1.0×10-5mol/L范围内成良好的线性关系,相关系数为0.9995,方法检出限为1.0×10-7mol/L。方法已用于加碘食盐中碘酸根含量的测定,平均回收率为100.7%。循环伏安(CV)测试表明,碘酸根在汞膜电极上电化学反应是不可逆过程。     

1—（4—偶氮苯基苯）—3—丙基—三氮烯键含硅胶修饰碳湖电板溶出伏安法测定饲料中镉的研究

以1-(4-偶氮苯基苯)-3-丙基-三氮烯键合硅胶(ABPT-SG)为修饰剂,液体石蜡为粘合剂,制备了ABPT-SG修饰碳糊电极。在pH8.0、浓度为0.2mol/L的氨性缓冲底液中,于-1.2V(Vs.SCE,下同)的电位下富集,将Cd2+以Cd-ABPT-SG络合物的形式吸附在电极上,用阳极溶出伏安法测定。在-0.60V处Cd有一灵敏的阳极溶出峰,峰电流与Cd2+的浓度在5.0×10-6～1.0×10-3mol/L范围内呈良好的线性关系,测定饲料中的镉,检出限为1.0×10-8mol/L。     

二氧化钛纳米管修饰电极测定食醋中镍含量

在pH 8.0的NH4Cl-NH3·H2O缓冲液中,-1.10V富集3min后,Ni 2+在阳极溶出扫描过程中会产生灵敏度高的特征溶出峰,据此建立了基于二氧化钛纳米管修饰电极线性扫描阳极溶出伏安法测定食醋中镍含量的新方法。优化了分析底液、富集电位与时间以及修饰剂用量等测定参数。在优化条件下,溶出峰电流与Ni 2+在3.0×10-7~5.0×10-5 mol/L浓度区间有较好的线性规律,检出限为1.0×10-7 mol/L(S/N=3)。运用本方法测定了食醋中的镍含量,结果满意。     

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