微波消解-石墨炉原子吸收法测定保健食品软胶囊壳中铬含量

目的:建立石墨炉原子吸收分光光度法测定保健食品软胶囊壳中铬含量的方法。方法:采用微波消解仪对样品进行消解,以石墨炉型原子吸收分光光度计对其铬含量进行测定。结果:铬在0-40ng/m L范围内线性关系良好,相关系数为0.9992,最低检出限为0.2ng/m L,回收率均在90-105%之间。结论:该方法简便、快捷,具有较高灵敏度、准确度、精密度和较低的检出限,适用于保健食品软胶囊壳中铬含量的测定。     

重庆市辖区保健食品胶囊壳中铬含量测定与风险评估

目的建立保健食品胶囊壳中铬含量测定前处理方法和分析条件,了解重庆市辖区内在售胶囊剂保健食品胶囊壳中铬含量状况,并进行安全风险评估,为有关部门制定保健食品用明胶空心胶囊质量标准提供数据参考。方法随机抽取重庆市辖区在售胶囊剂保健食品121批,采用微波消解法进行样品前处理,以石墨炉原子吸收法测定胶囊壳中铬含量,并进行方法学研究。结合人体最大耐受剂量,进行安全风险评估。结果方法线性关系在5~50μg/L范围内良好,检出限为0.90μg/L,精密度和稳定性良好,回收率在92.3%~108.6%之间。121批样品胶囊壳中铬含量均低于2 mg/kg。结论该方法线性关系良好,检出限、精密度、稳定性和回收率均可满足分析要求。参照《中国药典》(2010年版)二部"明胶空心胶囊"项下限量标准(≤2 mg/kg)进行评价,均符合要求。按人体最大耐受剂量进行评估,抽查的保健食品胶囊壳中铬含量对人体健康无安全风险。     

食用明胶中微量铬含量测定的方法研究

为优化食用明胶中微量铬测定方法,通过微波消解,湿法消解,干法灰化等3种前处理方法,采取原子吸收-石墨炉法和电感耦合等离子质谱法测定明胶中铬含量。结果表明,食用明胶经硝酸-双氧水消解体系进行微波密闭消解,采用原子吸收-石墨炉法测定其微量铬,铬在0～16 ng/mL浓度范围内线性关系良好,相关系数r~2=0.999 1,方法检出限为0.01 mg/kg,加标平均回收率98.7%,相对标准偏差1.7%(n=7),质控样测定结果接近其中值。     

微波消解-石墨炉原子吸收光谱法测定大米中铬

建立微波消解-石墨炉原子吸收光谱法测定大米中重金属铬含量的方法。采用微波消解法对样品进行消解,用石墨炉在波长357.9 nm处测定样品中铬的含量。结果表明,该方法线性关系良好,相关系数为0.999 7,检出限为0.006 mg/kg,定量限为0.02 mg/kg,回收率为81.6%～93.1%。该方法具有快速、简便、准确等优点,可用于大米中铬的含量测定。     

微波消解-原子吸收分光光度法测定保健食品中铝元素含量

目的建立微波消解-石墨炉原子吸收分光光度法测定固体、液体和软胶囊3种基质的保健食品中铝元素含量的分析方法。方法前处理方法经实验确定为5 mL硝酸和2 mL过氧化氢(30%,V:V)双溶剂消解,经微波消解仪消解,采用石墨炉原子吸收分光光度测定保健食品中铝元素的含量。结果铝元素在0～500μg/mL的浓度范围内线性关系良好,相关系数为0.998;铝元素的检出限为0.24 mg/kg;回收率为81.2%～98.7%;相对标准偏差小于3.2%(n=6)。结论该方法操作简单、灵敏度高、检出限低,满足保健食品中铝元素含量的测定。     

全自动石墨加热消解-石墨炉原子吸收法测定麦苗粉中铅含量的不确定度评定

目的评定全自动石墨加热消解-石墨炉原子吸收法测定麦苗粉中铅含量的不确定度。方法麦苗粉样品经全自动石墨加热消解后,石墨炉原子吸收法测定,外标法定量,根据建立的数据模型对每个不确定度分量进行评定,最终得出对合成不确定度的贡献度。结果置信概率为95%,取包含因子k=2,湿法消解-石墨炉原子吸收法测定麦苗粉中铅含量结果报告为X=(0.17±0.01)mg/kg。结论该方法测量铅不确定度的主要因素是曲线拟合的不确定度。     

快速消解-石墨炉原子吸收光谱法测定食品中砷含量

目的 建立快速消解-石墨炉原子吸收光谱法测定食品中砷含量的方法。方法 采用快速消解法消解3类食品,用石墨炉原子吸收光谱法测定砷的含量。结果 本实验测定砷的方法检出限和定量限分别为0.051 mg/kg和0.170 mg/kg。与微波消解-原子荧光法测定结果相比,两种方法测定大米和茶叶的绝对差值占算数平均值分别为7.2%、7.6%,两种方法测定奶粉中砷的结果均为0 mg/kg。快速消解-石墨炉原子吸收光谱法的回收率在83.1%~94.4%。结论 本实验建立的快速消解-原子吸收光谱法测定食品中砷的检测方法准确、可靠,适用于食品中砷含量的检测。     

原子吸收光谱法测定四季感冒片铬含量

目的测定市场上四季感冒片铬含量,为制定四季感冒片标准提供参考数据。方法采用硝酸浸泡过夜,微波消解,石墨炉原子吸收光谱法测定。结果线性相关系数为0.9981,加样回收率96.9%,检出限0.41 ng/mL,重复性RSD为1.6%(n=6)。结论此法可用于四季感冒片质量控制,结果表明,市场上四季感冒片铬含量潜在风险较低。     

微波消解-电感耦合等离子体发射光谱法测定明胶中铬含量

采用微波消解-电感耦合等离子体发射光谱法与石墨炉原子吸收光谱法测定了考核样明胶中的铬含量,并与石墨炉原子吸收法的测试结果进行比较,发现电感耦合等离子体发射光谱仪(inductively coupled plasma optical emission specrometry,ICP-OES)法能够更加快速、准确地对样品进行分析,具有更高的稳定性和更低的检出限,这为ICP-OES法在食品铬含量测定中的研究提供可靠的试验数据支持。     

石墨炉法测定食用明胶铬时三种前处理的比较

为找到适合原子吸收光谱法测定食用明胶铬含量的前处理方法,对干式消解法、微波消解法和湿式消解法进行对比。结果发现,干式消解法使得明胶标准物质(铬含量1.5±0.15 mg/kg)中的铬有较大的损失,测定结果仅为0.91 mg/kg,测定结果需用回收率进行校正;微波消解法和湿式消解法的测定结果分别为1.40和1.61 mg/kg,方法检出限分别为0.08和0.12 mg/kg,精密度(n=7)分别为3.3%和2.2%,结果准确可靠。在使用GB 5009.123—2014原子吸收石墨炉法测定食用明胶中的铬时,应优先采用微波消解和湿式消解的样品前处理方法。     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

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.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.