固相萃取-高效液相色谱-柱后衍生荧光法测定奶粉中维生素B11含量

建立了固相萃取-高效液相色谱-柱后衍生荧光法用于测定奶粉中维生素B11含量。奶粉酶解样液经固相萃取小柱纯化后,在ZORBAX SB-C18色谱柱上,以pH=3.5、浓度为0.05mol/L磷酸二氢钾-乙腈体系为流动相,流速为1.0mL/min,进样量20μL,以0.5%过硫酸钾溶液为衍生试剂,反应器温度为60℃,流速0.5mL/min,经荧光检测器(Ex=365nm,Em=440nm,增幅值100,衰减值16)检测定量。结果表明:在0.02～1.76μg/mL范围内该方法线性良好,R2=0.9999,检测限为4ng/mL,定量限为12ng/mL,灵敏度足以满足奶粉检测的需要,方法回收率在92.5%～95.7%之间,变异系数为1.32%。     

气相色谱-质谱法测定牛奶和奶粉中啶酰菌胺残留

建立了一种牛奶和奶粉中啶酰菌胺残留的气相色谱-质谱测定方法.试样中的啶酰菌胺用乙腈提取,提取液经盐析、离心、浓缩和溶剂交换后,经凝胶渗透色谱净化,用气相色谱-质谱仪测定,外标法定量.方法的线性范围是0.010～0.50 mg/L.定量检出限(LOQ)牛奶为0.005 mg/kg,奶粉为0.040 mg/kg(均为质量分数),牛奶好奶粉中啶酰菌胺的添加质量分数为0.010,0.020,0.050 mg/kg时,回收率为88.6%～90.7%,相对标准偏差(RSD)为4.08%～5.95%.方法灵敏度高、选择性强、重现性好,适用于牛奶和奶粉中啶酰菌胺残留的定性确证和定量测定.     

离子色谱法测定奶粉中的葡萄糖、蔗糖和乳糖

建立高效阴离子交换色谱-脉冲安培检测法测定奶粉中葡萄糖、蔗糖和乳糖的方法。以METROSEP CARB 1(150mm×4.0mm)阴离子交换柱为分离柱,脉冲安培检测,37mmol/L NaOH溶液为淋洗液,以柠檬酸作为蛋白质沉淀剂。葡萄糖、蔗糖和乳糖的线性范围分别为1～40、1～50、1～50mg/L,相关系数分别0.9966、0.9968、0.9985,检出限分别为0.014、0.091、0.083mg/L,精密度为1.10%～4.96%,回收率为90.13%～104.83%。该方法分析时间短,前处理简单,适用于快速测定奶粉中的葡萄糖、蔗糖和乳糖。     

分光光度法和高效液相色谱法测定啤酒中残留直链烷基苯磺酸钠含量

目的建立分光光度法和高效液相色谱法测定啤酒中残留直链烷基苯磺酸钠的分析方法。方法确定实验过程主要参数。制作吸光度浓度工作曲线,定量样品检测结果。采用液液萃取法提取样品中的直链烷基苯磺酸钠,在最佳色谱条件下,制作了阴离子表面活性剂(以十二烷基苯磺酸钠计)标准曲线,采用峰高外标法定量样品检测结果。结果通过实验验证亚甲蓝活性物质(methylene-blue active substances,MBAS)的特征吸收波长为652 nm,表观摩尔吸光系数ε=1.93×10~6 L/(mol·cm),检出限为4.04×10~(-3)mg/L,检测方法回收率73.4%～104.5%,相对标准偏差3.04%,线性范围为4.04×10~(-3)～2.0 mg/L。在确定的最佳实验条件下检测了6份啤酒样品,其中直链烷基苯磺酸钠残留量在0.024～0.036 mg/L之间。高效液相色谱法的线性范围是2.0～200 mg/L,检出限为2.05×10~(-3) mg/L,回收率为78.6%～98.5%,相对标准偏差≤8.9%。在确定的最佳色谱条件下检测了6个样品,测得啤酒中直链烷基苯磺酸钠的残留量在0.014～0.022 mg/L之间。结论液液萃取高效液相色谱法检测结果的准确度略高于分光光度法,但不宜在低浓度(2 mg/L)下作标准曲线。对啤酒中残留直链烷基苯磺酸钠的直接快速检测宜选取分光光度法,而准确检测则优先选用液液萃取高效液相色谱法。     

超高效液相色谱-串联质谱法测定奶粉中 己烯雌酚及玉米赤霉烯酮

目的建立超高效液相色谱-串联质谱法测定奶粉中己烯雌酚(diethylstilbestrol,DES)及玉米赤霉烯酮(zearalenone,ZEN)的分析方法。方法采用QuEChERS提取方法,奶粉加水浸润后用乙腈提取,加入氯化钠促使乙腈和水分层,取乙腈层经中性氧化铝小柱净化。以乙腈和水作为流动相,经ACQUITY UPLC?BEH C_(18)色谱柱分离后,利用超高效液相色谱-串联质谱法在电喷雾负离子模式下进行测定,内标法定量。结果DES和ZEN在5.0～100.0μg/L范围内线性关系良好(r~20.995),在5、10和50μg/kg 3个加标浓度水平下, DES和ZEN的回收率在91.5%～97.5%和92.5%～95.7%之间,相对标准偏差小于5%。结论该方法灵敏度高,定量准确,可同时测定奶粉中的己烯雌酚及玉米赤霉烯酮。     

免疫亲和柱-高效液相色谱法检测乳制品中氯霉素

建立免疫亲和柱富集净化、高效液相色谱-紫外法快速测定牛奶和奶粉中氯霉素残留物。样品用乙酸乙酯提取,经免疫亲和色谱柱纯化,应用液相色谱-紫外法检测。结果表明,牛奶和奶粉添加氯霉素,回收率为79.6%~108.6%,变异系数小于10%;方法检测灵敏度0.1μg/L。该方法能够特异性的纯化牛奶和奶粉样品中的氯霉素,免疫亲和柱(IAC)净化是一种简单,快速,准确的方法。     

氧弹燃烧-离子色谱法测定婴儿配方奶粉中的氯

建立采用氧弹燃烧-离子色谱法测定婴儿配方奶粉中的氯含量的条件及方法。以氧弹对婴儿配方奶粉试样进行燃烧,10 mmol/L NaOH为吸收液进行吸收,以Dionex IonPac AS 11-HC柱,KOH梯度淋洗,流速为1.0 mL/min。经离子色谱分离测定婴儿配方奶粉中的氯的含量。氯离子的方法检出限为13.2μg/L。利用该方法对婴儿配方奶粉中的氯进行测定,线性相关系数为0.999 9,平均回收率为91.0%～95.5%,相对标准偏差为1.9%～3.5%。     

液质联用法同时测定婴幼儿配方乳粉中氯酸盐和高氯酸盐残留

建立了婴幼儿配方乳粉中氯酸盐和高氯酸盐残留的高效液相色谱-串联四极杆质谱联用测定方法。样品经水超声溶解,乙腈除蛋白。以PC HILIC色谱柱分离,流动相为浓度50 mmol/L的乙酸铵水溶液和乙腈,流速0.25 mL/min。液相色谱-串联质谱仪测定,基质内标法定量。在该优化条件下,氯酸盐和高氯酸定量限分别为20μg/kg和2.0μg/kg,方法回收率为85.1%～94.7%,相对标准偏差(RSD)为2.38%～9.79%。经测定多种市售婴幼儿配方奶粉,表明该方法操作简单、测定结果准确,可用于婴幼儿配方奶粉中氯酸盐和高氯酸盐残留的同时快速测定。     

奶粉中N-乙酰神经氨酸的检测

建立一种高效液相色谱荧光测定奶粉中N-乙酰神经氨酸(N-acetylneuraminic acid,Neu5Ac)含量的分析方法。该方法利用酸水解释放出奶粉中的Neu5Ac,用邻苯二胺盐(OPD)作为衍生化试剂,80℃避光衍生100 min,采用高效液相色谱荧光检测。色谱条件为:用Thermo Hypersil GOLD柱(250mm×4.6mm, 5μm)分离;流动相选择超纯水-乙腈作为梯度洗脱,柱温为30℃,流速为1.0mL/min;进样体积为10μL;荧光检测器激发波长为337 nm,发射波长为448 nm。结果表明:N-乙酰神经氨酸在0.5～200μg/g范围内线性关系良好(R~2=0.9994),回收率为98%～119%,检出限为0.5μg/g。该方法具有灵敏度高,重复性好等特点,可准确测定市售奶粉中N-乙酰神经氨酸的含量。     

同位素内标UPLC -MS/MS法测定婴儿配方奶粉中性激素苯甲酸雌二醇残留

建立测定婴儿配方奶粉中性激素苯甲酸雌二醇的超高效液相色谱-串联质谱方法。样品前处理采用酶解、甲醇提取,经LC-C18和LC-NH2基固相萃取柱净化。苯甲酸雌二醇由超高效液相色谱-串联质谱(UPLC-MS/MS)分离、在正离子电离模式(ESI+)及多反应监测模式(MRM)下,以氘代诺龙-d3为内标进行定量检测。方法对婴儿配方奶粉中苯甲酸雌二醇的检出限(LOD)0.39μg/kg,定量限(LOQ)为0.95μg/kg。在4μg/kg和10μg/kg两个加标水平下,婴儿配方奶粉中苯甲酸雌二醇的回收率在76.5%～86.3%的范围内,相对标准偏差在9.7%～15.2%范围内。     

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