超高效液相色谱-三重四级杆质谱法测定猪肉中氯霉素残留量的不确定度评定

目的采用超高效液相色谱-三重四级杆质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)测定猪肉中的氯霉素残留量,并进行不确定度评定。方法依据JJF1059.1-2012《测量不确定度评定与表示》,结合数学模型和实验过程,分析测定结果的主要测量不确定度来源,评定各标准不确定度的分量。结果不确定度主要来源于标准溶液配制和标准曲线拟合。当猪肉中氯霉素残留量测定结果为1.07μg/kg时,其扩展不确定度为0.12μg/kg,结果表示为(1.07±0.12)μg/kg (k=2)。结论该评定方法适用于超高效液相色谱-串联质谱法测定猪肉中氯霉素残留量的不确定度分析,可以为科学评价药物残留测量结果的准确性提供依据。     

液相色谱质谱联用仪测定沙丁胺醇的不确定度评定

目的:全面地分析液相色谱-串联质谱法测定沙丁胺醇的不确定度来源与影响不确定度的因素。在测量结果处于临界状态时,对测量结果作出正确判定。方法:通过建立数学模型,依据JJF 1059.1-2012《测量不确定度评定与表示》、JJG 196-2006《常用玻璃量器检定规程》和GB/T 22286-2008《动物源性食品中多种β-受体激动剂残留量的测定液相色谱串联质谱法》的规定,逐层对测量过程中的不确定度来源进行分析,最后给出合成不确定度和扩展不确定度。结果:按照GB/T 22286-2008《动物源性食品中多种β-受体激动剂残留量的测定液相色谱串联质谱法》测定沙丁胺醇的不确定度为1.54μg/kg。     

液相色谱-串联质谱法测定牛奶中氯霉素残留量的不确定度评定

目的采用液相色谱-串联质谱法对牛奶中氯霉素的残留量进行不确定度评定。方法根据GB29688-2013《牛奶中氯霉素残留量的测定液相色谱-串联质谱法》建立数学模型,根据JJF 1059.1-2012《测量不确定度的评定与表示》对测量结果的各不确定度来源进行分析和量化。结果本方法的不确定度主要来自于标准曲线的建立及测定结果重复性。当氯霉素的添加水平为0.1064 ng/g时,氯霉素的结果可表示为0.1064±0.0457 ng/g(k=2)。结论该评定方法清晰合理,简便准确,可适合液相色谱-串联质谱法对牛奶中氯霉素的残留量测定的不确定度评定。     

超高效液相色谱-串联质谱法测定猪肉中β-受体激动剂残留量的不确定度分析

采用超高效液相色谱-串联质谱法对猪肉中沙丁胺醇、盐酸克伦特罗和莱克多巴胺含量的不确定度进行评估。根据JJF 1135—2005《化学分析测量不确定度评定》和JJF 1059.1—2012《测量不确定度评定与表示》中的有关规定,建立测定猪肉中3种β-受体激动剂残留量不确定度的数学模型,逐层对不确定度来源进行分析。通过对不确定度分量进行量化和合成,得出当猪肉中沙丁胺醇含量为1.99μg/kg时,其扩展不确定度为0.25μg/kg(k=2);当猪肉中盐酸克伦特罗含量为2.04μg/kg时,其扩展不确定度为0.24μg/kg(k=2);当猪肉中莱克多巴胺含量为1.97μg/kg时,其扩展不确定度为0.24μg/kg(k=2)。评定结果表明,影响检测结果的主要因素为标准溶液配制、标准曲线拟合和测量重复性等。     

液相色谱串联质谱内标法测定猪肉中沙丁胺醇及莱克多巴胺残留量的不确定度分析

目的对液相色谱串联质谱内标法测定猪肉中沙丁胺醇、莱克多巴胺2种β-受体激动剂残留量的不确定度进行分析。方法采用液相色谱串联质谱以沙丁胺醇D_3为内标对猪肉中沙丁胺醇、莱克多巴胺2种β-受体激动剂残留量进行测定;建立数学模型,对测量重复性、标准物质纯度、标准溶液配制、内标物质添加、仪器进样体积等不确定因素进行评定。结果当猪肉中沙丁胺醇、莱克多巴胺残留量分别为11.004μg/kg和11.770μg/kg时,其扩展不确定度分别为2.628μg/kg和2.839μg/kg (k=2)。结论标准曲线拟合过程、仪器进样体积、标准系列配制过程对检测结果影响最大。     

气相色谱-串联质谱法测定果汁中毒死蜱残留量的不确定度评定

目的评定气相色谱-串联质谱法测定果汁中毒死蜱残留量的不确定度。方法依据国家计量技术规范JJF 1059.1-2012《测量不确定度评定与表示》对毒死蜱测定中的不确定度来源进行分析,通过建立数学模型量化不确定度分量,计算合成不确定度和扩展不确定度。结果本方法的不确定度主要来源于标准曲线的配制和样品的稀释过程。当果汁中毒死蜱残留量为41.1μg/kg,扩展不确定度为9.8μg/kg,毒死蜱残留量表示为(41.1±9.8)μg/kg(k=2)。结论该评定方法可用于气相色谱-串联质谱法对果汁中毒死蜱残留量的不确定分析。     

UPLC-MS/MS技术测定猪肉中甲氧氯普胺不确定度评价

对超高效液相色谱-串联质谱测定猪肉中甲氧氯普胺残留量过程中可能影响到结果准确性的因素进行了分析。根据行业标准SN/T 2227-2008《进出口动物源性食品中甲氧氯普胺残留量检测方法液相色谱法-质谱/质谱法》,建立不确定度评价的数学模型,通过不确定度来源分析建立不确定度的评价方法。结果表明:标准溶液浓度产生的不确定最大,随机效应引入的不确定度次之,样品定容产生的不确定度最小。猪肉中甲氧氯普胺残留量为50.1μg/kg时,其扩展不确定度为5.0μg/kg（k=2）。      

液相色谱-串联质谱法测定牛奶中地塞米松残留量的不确定度评定

目的评定液相色谱-串联质谱法测定牛奶中地塞米松残留量的不确定度。方法样品经过固相萃取柱净化处理后,经色谱柱分离,流动相等度洗脱,多反应监测模式进行检测。依据JJF10591.1-2012《测量不确定度评定与表示》,考察称量、标准溶液配制、标准曲线拟合、测量重复性等主要因素引入的不确定度,幵对不确定度的各分量进行计算和合成。结果当牛奶中地塞米松添加量为3.67μg/kg时,在95%的置信区间下,其扩展不确定度为0.198μg/kg(k=2)。评定结果表明,实验过程的不确定度主要来源于曲线拟合、测量的重复性。结论该斱法准确可靠,适用于液相色谱-串联质谱法测定牛奶中地塞米松残留量的不确定度评定,对检测结果准确度的提高具有指导意义。     

UPLC-MS/MS技术测定猪肉中甲氧氯普胺不确定度评价

对超高效液相色谱-串联质谱测定猪肉中甲氧氯普胺残留量过程中可能影响到结果准确性的因素进行了分析。根据行业标准SN/T 2227-2008《进出口动物源性食品中甲氧氯普胺残留量检测方法液相色谱法-质谱/质谱法》,建立不确定度评价的数学模型,通过不确定度来源分析建立不确定度的评价方法。结果表明:标准溶液浓度产生的不确定最大,随机效应引入的不确定度次之,样品定容产生的不确定度最小。猪肉中甲氧氯普胺残留量为50.1μg/kg时,其扩展不确定度为5.0μg/kg(k=2)。     

超高液相色谱-串联质谱法测定猪肉中8种喹诺酮类兽药残留的不确定度评定

目的评定超高液相色谱-串联质谱法测定猪肉中8种喹诺酮类兽药残留量的不确定度。方法根据JJF 1135-2005《化学分析测量不确定度评定》和JJF 1059.1-2012《测量不确定度评定与表示》中的有关规定,建立不确定度的数学模型,逐层对不确定度进行分析。结果添加量为1.0μg/kg时,8种喹诺酮类兽药残留量测定的相对标准不确定度为2.77%~6.65%;添加量为2.0μg/kg时,8种喹诺酮类兽药残留量测定的相对标准不确定度为1.69%~6.67%;添加量为4.0μg/kg时,8种喹诺酮类兽药残留量测定的相对标准不确定度为1.31%~5.43%。结论在实际检测中,提高天平精度及定容精度,控制标准溶液配制过程,提高检验员工作质量和效率均可降低引入的不确定度,使检测结果更可靠。     

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