蜜饯中乙酰磺胺酸钾测定方法的探讨

探讨蜜饯中乙酰磺胺酸钾用高效液相色谱测定的方法.利用乙醚对样品进行提取,乙醚提取液用水浴挥发干后,加入流动相定容后用高效液相色谱仪测定[色谱柱:SpheriosorC18;流动相:硫酸铵(0.02mol/L)(740ml) 甲醇(170ml) 乙腈(90ml) 10%H2SO4(1ml);流速:0.7ml/min;进样量:10ul;波长:214nm],同时进行回收率、精密度,线性关系的试验.结果在选定的色谱条件下,标准曲线的线性关系良好,其相关系数为0.999,相对标准偏差为0.15%～0.21%(n=6);样品加回收率为91.6%-105%;乙酰磺胺酸钾和糖精钠的最低检出浓度分别为5.0 mg/kg和5.0mg/kg.可见用乙醚提取处理蜜饯,检测其中的乙酰磺胺酸钾,糖精钠含量,精密度、加标回收率、线性关系等均满足检测要求,方法比较准确.     

高效液相色谱法同时测定食品中苯甲酸、山梨酸、糖精钠、乙酰磺胺酸钾的含量

对同时测定食品中常用的四种添加剂(苯甲酸、山梨酸、糖精钠、乙酰磺胺酸钾)的方法进行分析研究。样品经水加热溶解后,加入乙酸锌和亚铁氰化钾作为沉淀剂提取后,以甲醇-0.02mol/L乙酸铵溶液为流动相,C18色谱柱分离,采用高效液相色谱法(HPLC)——二极管阵列检测器,在检测波长230nm,参比波长214nm处定量检测。4种组分分离完全,线性关系良好,加标回收率为89%～105%,测定结果的相对标准偏差小于4.1%(n=6)。该方法检出限低,简单、快速、准确,可用于食品中苯甲酸、山梨酸、糖精钠、乙酰磺胺酸钾的同时测定,为各个实验室的日常检测工作节省大量的时间。     

乳饮料中乙酰磺氨酸钾的测定

目的:建立高效液相色谱法测定乳饮料中乙酰磺胺酸钾的检测方法.方法:选用乙腈和适当的沉淀剂对样品处理,对检测条件进行了优化.结果:在0.02mol/L硫酸铵:甲醇:乙腈(870/100/30,v/v/v)为流动相,流速0.8mL/min,检测波长214nm的条件下,样品中的乙酰磺胺酸钾可得到很好的分离.     

微量技术在常量测定中的应用——原子吸收法测定乙酰磺胺酸钾中的钾

用简单的混酸消化法处理样品，用微富燃火焰原子化以及采用钾的非灵敏线进行原子吸收法测定，对乙酰磺胺酸钾中常量钾的分析结果表明，这一方法比FCC法的准确度和精密度都高．     

饮料中乙酰磺胺酸钾含量测定能力验证结果分析

目的评价实验室测定饮料中乙酰磺胺酸钾的能力和水平,并对结果可疑或不满意的实验室提出技术建议。方法制备样品,采用单因素方差分析和t检验对样品均匀性和稳定性进行分析。向82家参与实验室随机发放样品,并在规定时间内回收有效数据。对能力验证结果进行稳健统计分析,用Z比分数评价实验室检测能力,并对离群数据从实验方法、原始记录等方面进行技术分析。结果在82家反馈结果的实验室中,68家结果为满意,满意率为82.9%,1家结果可疑,13家结果为不满意。结论本次能力验证活动中,多数参加此次能力验证项目的实验室评价结果为满意,表明对乙酰磺胺酸钾的检测能力总体良好。实验室结果离群的主要原因是操作不规范,在今后的工作中可通过加强实验室质量体系建设来改善。     

离子选择性电极法测定卡拉胶中钾含量

卡拉胶中钾离子的含量会影响卡拉胶的凝固性,为测定卡拉胶中钾的含量,本实验将商品卡拉胶用盐酸-硝酸(1:3)湿法处理后,配成一定浓度的溶液,用四苯硼钠滴定法做对照,采用钾离子选择性电极法对卡拉胶中的钾含量进行了测定,建立了一种简便、快速、准确的测定卡拉胶中钾含量的方法,标准曲线方程:y=48.14x 175.45,相关系数为0.9942。用此方法测得卡拉胶样品中的钾含量为5.36%,相对标准偏差(RSD)为0.65%。     

甜味剂乙酰磺胺酸钾在冷冻饮品中的应用

在规定的范围内,通过从产品的口感,组织状态,风味及甜度等方面研究甜味剂乙酰磺胺酸钾在冷冻饮品中的应用。得出了人工合成甜味剂乙酰磺胺酸钾应用在冷冻饮品可得到良好的口味,且不影响混合料的熔化和搅打性能。此结果对冷冻饮品的发展具有一定的经济意义。     

茶叶中钾、镁、锰含量的测定与分析

用火焰原子吸收法测定了几种茶叶中钾、镁、锰的含量,并进行了精密度的和加标回收率的测定,结果表明,茶叶中钾、镁、锰含量丰富,不同品种茶叶中钾、镁、锰含量有所差异.试验证明,该方法准确可靠.     

卷烟纸中钾、氯和硝酸盐含量的测定

采用连续流动分析法测定了卷烟纸中钾、氯和硝酸盐的含量 ,其回收率分别为 97.5 %、90 .0 %和 92 .0 % ,变异系数为 2 .17%、5 .5 6%和 1.4 6%。并与国家标准规定的方法进行了对比 ,测定结果与国家标准规定的方法比较一致。同其它方法相比 ,该方法具有操作简单、测试准确、快速等优点     

食用醋中乙酰磺胺酸钾测定的探讨和改进

改进了食用醋中乙酰磺胺酸钾的检测方法。建立了以ZORBAX Eclipse Plus C18(4.6mm×100mm,3.5mm)为液相色谱柱;以甲醇、10mmol/L乙酸铵(pH为4.0)为流动相;检测波长为214nm;流速为1.0mL/min的检测方法,讨论了滤出液体积的选择、洗脱液体积的选择。结果表明:乙酰磺胺酸钾在0~8.0μg/mL内具有良好的线性关系,检出限为1.42μg/mL,加标回收率在92.1%~97.5%。与国标方法相比较,提高了方法的灵敏度、准确度及精密度。     

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.     

Detection of adulteration of locust bean gum with guar gum by capillary electrophoresis and polarized light microscopy

Capillary electrophoresis (CE) and polarized light microscopy (PLM) were utilized in the detection of the adulteration of locust bean gum with guar gum. For CE analyses, standards of locust bean and guar gums were extracted with 30% CH₃CN, removing the residual proteins from the gum matrix. A 8.75 mM NaH₂PO₄-20.6 mM Na₂B₄O₇ buffer, pH 9, was used to separate these proteins and to identify marker proteins that were present in the guar gum. These markers did not co-migrate with components in the extracts of mechanically processed locust bean gum, and are used as indicators of adulteration. Using PLM with toluidine blue and iodine staining techniques, unadulterated locust bean gum samples were distinguished from mixed samples through the differential staining of components in locust bean versus guar and tara gums. These experiments in the use of CE and PLM provide orthogonal and complementary methods for the verification of 'true' positives and the elimination of 'false' positives.     

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%.