毛细管电泳-电化学检测测定荞麦中表儿茶素、芦丁、槲皮素的含量

用毛细管电泳-电化学检测的方法研究了荞麦中黄酮类物质:表儿茶素、芦丁、槲皮素的含量,研究了电极电位、缓冲液的pH值、分离电压及进样时间对电泳的影响,得到优化的测定条件。以直径为300μm的碳圆盘电极为检测电极,工作电极电位为0.95V(vs.SCE),在50mmol/L硼砂(pH8.5)运行缓冲液中,上述3组分在12min内完全分离。表儿茶素、芦丁、槲皮素线性范围分别为5×10-7￣1×10-4g/mL、1×10-6￣1×10-4g/mL、1×10-6￣1×10-4g/mL;检出限分别为1.83×10-7g/mL、2.9×10-8g/mL、1.00×10-7g/mL;3种标样7次平行进样的相对标准偏差(RSD)小于2.5%;回收率表儿茶素100.4%、芦丁98.1%、槲皮素100.1%(n=3)。该法灵敏可靠,结果令人满意。     

毛细管电泳安培检测法快速测定巧克力中的香兰素

运用毛细管电泳安培检测法研究了巧克力中香兰素的快速测定方法,研究了电极电位、缓冲液的浓度和pH、分离电压以及进样时间等因素对分离测定的影响。在30mmol/L的硼砂(pH9.24)运行缓冲液中,施加15kV的分离电压及 0.65V(vs.SCE)的电极电位条件下,铜电极对香兰素有很好的响应。香兰素在5.0×10-6～1.0×10-3g/mL范围内存在较好的线形关系,检测限为3.87×10-7g/mL(S/N=3)。对实际样品的测定,回收率为96.5%～102.8%,结果令人满意。     

线性扫描伏安法测定食盐中碘含量

以多壁碳纳米管(MWCNT)修饰玻碳电极为工作电极,研究了碘离子在该修饰电极上的伏安分析特性,建立了测定食盐中碘含量的线性扫描伏安法。在优化实验条件下,氧化峰电流与碘离子浓度在1.0×10-6～1.0×10-3 mol/L范围内呈良好的线性关系,检出限为4.0×10-7 mol/L。对1.0×10-4 mol/L碘化钾溶液平行测定10次的RSD为3.2%。将该方法用于测定加碘食盐中的碘含量,结果满意。     

玻碳电极的石墨烯修饰研究及其电化学应用

为了提高重金属镉的测定速度,本研究采用石墨烯(R-GO)对玻碳电极进行修饰,并应用于食品中镉的测定。采用滴涂法将氧化石墨烯修饰到玻碳电极表面,考察了电解质及p H、修饰剂用量、富集时间和富集电位对镉离子检测的影响,并优化了检测条件,建立了测定大米制品中镉的差分脉冲伏安分析法(DPV)。结果表明镉离子的溶出峰电流与其浓度在4×10-8~3×10-5g/L(r=0.9962)范围内呈良好的线性关系,检测限为3.0×10-9g/L。使用石墨烯修饰电极对镉含量为4.0×10-6g/L溶液平行测定6次的RSD为8.53%。将本法应用于大米样品中镉的检测可以得到平均回收率为96.25%~111.25%。石墨烯修饰玻碳电极体现出良好的稳定性、重现性,在裸玻碳电极检测的基础上降低了检出限,故本法是一种可靠、快捷、灵敏的检测方法,为快速监测食品中的镉元素提供技术支撑。     

苏丹红Ⅰ在活化玻碳电极上的电化学行为研究及其应用

利用循环伏安法在0.5 mol/L H2SO4溶液中制备了活化玻碳电极并对苏丹红Ⅰ在该电极上的电化学行为进行了研究。结果表明:活化玻碳电极对苏丹红Ⅰ的电化学氧化具有明显的催化作用。利用此催化性能,建立了一种新的测定苏丹红Ⅰ的电化学方法。在pH=4.0磷酸盐缓冲溶液中,对检测条件进行了优化,利用差分脉冲伏安法进行测定,苏丹红Ⅰ在活化玻碳电极上的氧化峰峰电流与其浓度在4.00×10-8¹.00×10-5mol/L内呈良好线性关系;相关系数为0.998 9;检出限为9.00×10-9mol/L。其回归方程为:ipa(A)=0.70c+5.91×10-7。该电极具有良好的灵敏性、选择性和稳定性,可用于食品中苏丹红Ⅰ的检测。     

毛细管电泳-电化学方法检测黄酒中多酚物质

采用毛细管电泳-电化学检测法(CE-ED)同时分离测定了黄酒中表儿茶素、芦丁、金丝桃甙、山萘酚、绿原酸、槲皮素等多种生物活性成分的含量.考察了运行缓冲液酸度和浓度、分离电压、氧化电位和进样时间等实验参数对分离、检测的影响.在最优化条件下,以300 μm碳圆盘电极为检测电极,检测电位为 950mV(vs.SCE),-40mmol/L硼砂的运行缓冲液(pH9.0)中,上述各组分在15min内可基本实现基线分离.各组分浓度与峰电流在3个数量级范围内呈良好线性,检测下限(S/N=3)分别为3.90x10-5g/L、8.09x10-5 g/L、2.96x10-5g/L、3.98x10-5g/L、1.46x10-4g/L和8.59x10-5g/L.     

多壁碳纳米管修饰电极测定烟酰胺

研究多壁碳纳米管修饰电极的制备及其对烟酰胺的电催化检测。考察支持电解质种类、酸度和扫速等因素对烟酰胺响应的影响。在优化实验条件下,采用示差脉冲伏安法测定烟酰胺,其浓度在5.0×10-5～1.0×10-3mol/L范围内与其还原峰电流呈良好的线性关系,检出限为2.49×10-5mol/L。共存的多种离子、蔗糖、乙醇等不干扰测定。     

Pt—Fe(Ⅲ)/MWCNTs修饰电极伏安法测定食品中的亚硝酸根

采用滴涂法和电化学沉积法构建Pt—Fe(Ⅲ)/多壁碳纳米管(MWCNTs)修饰玻碳电极(Pt—Fe(Ⅲ)/MWCNTs/GCE),研究该修饰电极对NO2-的电催化作用,并优化试验条件,在该基础上建立一种差分脉冲伏安法(DPV)测定NO2-的新方法。NO2-的氧化峰电流与其浓度在3.0×10-7~2.0×10-3 mol/L范围内呈良好的线性关系(r=0.999 3),检测限为1.0×10-7 mol/L,将该方法用于食品中NO2-的测定,效果满意。     

电化学法快速测定芹菜总黄酮含量

利用差分脉冲伏安法对芹菜总黄酮进行定量分析。选择芦丁纯品作为测定芹菜总黄酮的标准品,以纯玻碳电极为工作电极,首先采用循环伏安法优化测定条件,然后在最佳测定条件下,采用差分脉冲伏安法测定芹菜中总黄酮的含量。试验表明,芹菜总黄酮氧化峰电流与其浓度在2.0×10-6 mol/L~1.3×10~(-4) mol/L范围内呈良好的线性关系,检出限达到1.2×10~(-11) mol/L(S/N=3)。     

用于快速检测沙丁胺醇的分子印迹传感器的制备及其在食品检测中的应用

首先通过电沉积纳米金,电聚合聚硫堇对玻碳电极表面进行了修饰,之后利用沙丁胺醇为模板分子,通过电聚合α-甲基丙烯酸,制备了一种选择性具有特异识别功能的纳米金/聚硫堇/沙丁胺醇分子印迹电化学传感器。实验采用循环伏安法和差分脉冲法,对不同的修饰电极进行了表征,优化电极的制备和测定条件,研究了印迹传感器对模板分子的选择性响应。结果表明:最佳制备条件下,模板分子:功能单体=1:4,聚合15圈,以0.5 mmol/L硫酸:乙腈(1:9,V/V)洗脱10 min,在pH=7.0的PBS溶液中进行DPV检测,线性范围为2.0×10~(-7)~1.0×10~(-4) mol/L,检测限为6.0×10~(-8) mol/L,S/N=3。该传感器灵敏度高,抗干扰能力强,重现和稳定性好。利用制备的分子印迹电化学传感器对食品中的沙丁胺醇进行了测定,回收率在86.5%~111.9%(n=3),结果令人满意。     

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.     

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