电位滴定法测定食用油中过氧化值不确定度的评定

根据测量不确定度评定与表示理论,对电位滴定法测定食用植物油的过氧化值进行不确定度评定,对影响测量过程的不确定度来源进行了分析.结果表明,该方法测定食用植物油中过氧化值的扩展不确定度为Ux=0.004 g/100g,提出通过精确配制标准溶液及多次重复测量的方法能够降低该分析方法的不确定度.     

电感耦合等离子体质谱法测定食用植物油中重金属元素的不确定度评定

目的评定电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry,ICP-MS)测定食用植物油中重金属元素铁和锰的含量不确定度。方法分析测定过程,找出不确定度来源,建立不确定度评定数学模型。对单个不确定度分量进行合成和扩展,建立电感耦合等离子体质谱法测定食用植物油中Fe、Mn的不确定度评定方法。结果食用植物油中Fe含量为(10.5±1.2)mg/kg,k=2;Mn含量为(5.81±0.99)mg/kg,k=2。结论影响结果不确定度的主要因素是样液浓度引入的不确定度,由拟合标准曲线求得样液浓度引入的不确定度分量最大,其次为样品回收率测试和测量重复性产生的分量,本研究为实验室内部质量控制提供了依据。     

食用植物油中酸价测定的不确定度评定

根据食用植物油中酸价测定的原理,全面考虑了整个分析过程的不确定度来源,建立其结果的数学模型,并计算其测定全过程的不确定度分量、结果标准不确定度及扩展不确定度。提出的方法适用于食用植物油中酸价测定的不确定度评定。     

气相色谱-质谱法测定食用植物油中3-氯丙醇酯的不确定评估

目的评估气相色谱-质谱法面积比法测定食用植物油中3-氯丙醇酯的不确定度。方法根据JJF1059.1-2012《测量不确定度的评定和表示》,不确定度的主要来源为标准品、检测仪器和样品等参数,同时对各不确定度分量进行合成和扩展。结果当取样量为0.0100 g,k=2(95%置信度),测得的食用植物油中3-氯丙醇酯含量为(6.04?0.10)mg/kg。结论本方法可为评定食用植物油中3-MCPD酯含量的测量结果和方法的可靠性提供科学依据。     

微波消解-石墨炉原子吸收光谱法测定食用植物油中痕量铅的不确定度评定

研究了微波消解-石墨炉原子吸收光谱法测定食用植物油中痕量铅的不确定度来源,并对其不确定度分量进行了定量评定,确定了相对标准不确定度和扩展不确定度。结果表明：微波消解-石墨炉原子吸收光谱法测定食用植物油中痕量铅的不确定度主要来源为计量器具校准、标准曲线拟合、实验人员读数和仪器测定重复性,其相对标准不确定度分别为0.048、0.022、0.016和0.013。当称样量为0.500 1 g时,铅含量为0.024 mg/kg,k=2（95%置信度）,扩展不确定度为0.003 mg/kg,测量结果可表示为（0.024±0.003）mg/kg。     

UPLC-MS/MS法测定食用植物油中乙基麦芽酚含量的不确定度评定

依据BJS 201708规定的检测方法,建立数学模型,评定超高效液相色谱-串联质谱法测定食用植物油中乙基麦芽酚含量的不确定度.通过对检测过程中各环节不确定度因素的来源进行分析并对其进行评定,计算合成不确定度.结果表明,测定过程中不确定度的来源主要是标准溶液配制和标准曲线拟合;研究测得植物油中乙基麦芽酚的含量为95.6μ...     

抑制电导离子色谱法测定蔬菜中硝酸盐的不确定度评定

硝酸盐是蔬菜中主要的无机酸盐之一,人体内大部分的硝酸盐通过食用蔬菜摄入,但硝酸盐摄入量过高会危害人体健康。本文依据GB 5009.33-2010《食品中亚硝酸盐与硝酸盐的测定》和JJF1059.1-2012《测量不确定度评定与表示》,对抑制电导离子色谱法测定蔬菜中硝酸盐的不确定度进行了评定。对测定过程产生的不确定分量进行了分类讨论,通过各分量相对标准不确定度,计算出合成标准不确定度和扩展不确定度。通过分析评估发现,测定不确定度的主要影响因素依次是前处理方法回收率、标准溶液及配制、样品制备均匀性,产生影响较小的不确定度分量是样品的称量和试液的定容,相对扩展不确定度为6.8%。     

电感耦合等离子体原子发射光谱法测定植物油中聚二甲基硅氧烷的不确定度分析

目的评定电感耦合等离子体原子发射光谱法测定植物油中聚二甲基硅氧烷的不确定度。方法按照GB 5009.254-2016对植物油中聚二甲基硅氧烷进行测定,参照JJF 1135-2015、JJF 1059.1-2012等标准建模,分析植物油中聚二甲基硅氧烷测定的不确定度的来源,幵对各不确定度分量进行量化和合成。结果当植物油中的检测结果为10.1 mg/kg时,其扩展不确定度为0.111 mg/kg(k=2)。结论影响检测结果的不确定度的主要因素为待测物浓度和回收率,样品称量、试样定容以及重复性测定引入的不确定度可以忽略不计。可以通过多次测量标线点、调整曲线范围、熟练实验步骤、增加平行样、保持仪器的稳定性等来减小测量不确定度。     

自动电位滴定法测定食用植物油过氧化值、酸值的不确定度评定

利用自动电位滴定方法对食用植物油中过氧化值和酸值进行测定，通过建立不确定度数学模型，分析和计算试验过程中影响过氧化值和酸值测量结果的不确定度分量和扩展不确定度。测试结果表明：食用植物油的过氧化值平均值为1.22 mmol/L，酸值平均值为1.43 mg/g，其过氧化值项目扩展不确定度为0.016 mmol/L，酸值扩展不确定度为0.044 mg/g，置信因子k=2，测量重复性是影响过氧化值和酸值实验结果不确定度的主要因素。     

气相色谱串联质谱法测定大米中联苯菊酯残留量的不确定度评定

对气相色谱串联质谱法测定大米中联苯菊酯残留量的测量不确定度进行评定。建立数学模型,分析不确定度来源,计算不确定度分量,并合成测量结果的不确定度,为实验室大米中联苯菊酯检测过程中的质量控制提供有效、可靠的检测数据。实验结果表明:当样品中联苯菊酯含量为0.044 0 mg/kg时,方法引入的扩展不确定度为0.000 82 mg/kg。通过比较各个分量不确定度,发现测量重复性带来的不确定度影响最大。     

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.     

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     

INFOPRINT 2014 was Successfully Held in Dongguan

Sponsored by Printing and Printing Equipment Industries Association of China （PEIAC） and organized by Print China magazine, the Seventeenth Beijing International Printing Information Conference （INFOPRINT 2014） was successfully held on 11th Dec. 2014 at Dongguan Exhibition International Hotel.