食品添加剂中砷和铅的微波消解-氢化物发生原子荧光法测定

采用微波消解方法,一次性分解样品,氢化物发生-原子荧光法,分别在硫脲、L-半胱氨酸和草酸、铁氰化钾存在下,实现了食品添加剂中砷、铅的测定,并对各种分析条件进行了优化和探讨。测定砷、铅回收率分别为97.0%~103.0%、98.7%~105.6%。检出限分别为0.35μg/L和0.12μg/L,用该方法测定食品添加剂中的砷、铅,结果满意。     

碰撞池-电感耦合等离子体质谱法快速检测化妆品中重金属

目的建立碰撞池—电感耦合等离子体质谱法(ICP-MS)测定复杂基质化妆品中铬、镍、砷、镉、汞、铅等重金属含量的快速检测方法。方法样品经过微波消解处理,用ICP-MS进行分析,八级杆碰撞反应池结合屏蔽炬技术消除质谱干扰,在线加入内标元素72Ge、115In和209Bi校正基体干扰。结果各元素校正曲线的相关系数均大于0.9992,方法检出限为0.4~2.2 ng/g,相对标准偏差小于5.69%,加标回收率为85.8%~104.2%,有证标准参考物质的测定结果与标准值相符。结论该方法前处理步骤简便快速,适用于复杂基质化妆品中多种有害元素的快速准确测定。     

高效液相色谱-碰撞/反应池-电感耦合等离子体质谱测定贝类中砷形态化合物及健康风险评估

本研究以九种青岛市售贝类样品为研究对象,并且通过高效液相色谱-碰撞/反应池-电感耦合等离子体质谱(HPLC-CRC-ICP-MS)测定总砷及砷形态化合物的含量,并对其食用安全性做出客观评价。样品采用超声提取(0.15 mol/L HNO₃),优化后的色谱条件(50 mmol/L(NH₄)₂CO₃,pH=9.5)进行色谱分离,并采用碰撞/反应池中O₂反应模式进行检测。6种砷形态化合物的线性回归方程相关系数均在0.999以上,检出限为0.009~0.028 μg/L,相对标准偏差在3.6%~8.3%之间,加标回收率在91.2%~106.2%。实验表明,青岛市售贝类样品中的砷元素主要以无毒性的AsB的形式存在,无机砷含量符合国标限量要求。     

碰撞反应池-电感耦合等离子体质谱法检测海藻食品中重金属

目的建立碰撞反应池—电感耦合等离子体质谱法(inductively coupled plasma-mass spectrometry,ICP-MS)测定海藻食品中铬、镍、铜、砷、镉、汞、铅等重金属元素的分析检测方法。方法样品经微波消解后用电感耦合等离子体质谱仪直接进行分析,采用内标元素72Ge、115In和209Bi消除基体干扰和信号漂移,碰撞反应池技术(ORS)消除质谱干扰。结果各元素校正曲线的相关系数均大于0.9992,方法的检出限0.003μg/L~0.028μg/L,相对标准偏差小于4.92%,加标回收率为85.6%~106.2%,标准参考物质的测定结果与标准值相符。结论该方法前处理操作简便快速,灵敏度高,重复性好,适用于海苔、海带、紫菜等海藻食品中多种元素的同时测定。     

电感耦合等离子体质谱仪进行白酒中39种元素分析的研究

建立了应用八级杆碰撞反应池-电感耦合等离子体质谱仪(ORS-ICPMS)测定白酒中锂、铍、硼、钠、镁、铝、钾、钙、钪、钛、钒、铬、锰、铁、钴、镍、铜、锌、镓、砷、锶、钇、镉、钡、镧、铈、镨、钕、钐、铕、钆、铽、镝、钬、铒、铥、镱、镥、铅等39种元素含量的方法。样品经硝酸消化,在线加入内标校正基质干扰,外标法定量,各元素校正曲线的相关系数均大于0.999。方法检出限0.001~9.6μg/L,方法加标回收率为80.5%~111.5%,相对标准偏差0.8%~5.0%(n=6)。     

电感耦合等离子体质谱法测定食品添加剂中的微量元素

建立了用带八极杆碰撞/反应池的电感耦合等离子体质谱仪(ORS-ICP-MS)测定食品添加剂食用二氧化钛中Be、Mg、Al、V、Cr、Mn、Fe、Ni、Cu、Zn、As、Cd、Sb、Ba、Hg、Pb等16种微量元素的方法。样品用硝酸+氢氟酸分解后,试液直接用ORS-ICP-MS法同时测定上述痕量元素含量。采用八极杆碰撞/反应池技术,有效地消除了多原子离子对待测元素的干扰,确定了实验的最佳测定条件。结果表明,各元素的检出限在0.002～0.186μg/g之间,加标回收率在92.2%～109.2%之间,相对标准偏差(RSD)小于3.38%。     

电感耦合等离子体质谱法测定再造烟叶中17种痕量元素

目的用微波消解结合电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry,ICP-MS)测量再造烟叶中的砷、钡、铍等17种痕量元素方法。方法再造烟叶样品经微波消解后,应用标准模式结合碰撞/反应池技术以及内标法定量进行电感耦合等离子体质谱法的测定,同时考察碰撞模式及碰撞气流量对测定结果的稳定性与准确性。结果 17种目标元素线性良好,相关系数r≥0.9995,检出限为0.001~0.065 mg/kg,加标回收率为79.3%~123.1%,相对标准偏差为1.15%~6.38%。结论该方法具有操作简便、分析时间短、稳定准确等优势,可满足烟草行业内大批量再造烟叶样品对痕量元素的分析测试。     

电感耦合等离子体质谱法测定米豆腐中5种元素的含量

目的建立电感耦合等离子体质谱法同时测定米豆腐中铅、砷、汞、镉、铬5种有害元素含量的分析方法。方法样品经微波消解,超纯水定容,以锗、铟、铋为内标物质,用电感耦合等离子体质谱法同时测定铅、砷、汞、镉、铬。结果铅、砷、汞、镉、铬回收率分别为83.2%~92.5%、85.3%~93.2%、83.5%~95.2%、85.7%~94.0%、81.7%~96.0%,相对标准偏差(n=6)分别为3.7%、2.3%、3.1%、2.9%、3.9%。5种元素线性关系良好,相关系数(n=6)在0.9997~1.000。结论优化了样品前处理方法和仪器参数,可用于米豆腐中铅、砷、汞、镉、铬的测定。     

微波消解—原子荧光光谱法测花椒制品中铅和砷

采用微波消解-原子荧光光谱法对花椒制品中铅和砷的测定条件(消解条件、酸浓度、硼氢化钾浓度等)进行了研究。结果表明:采用HNO_3-H_2O_2(5∶2)消化体系为消化剂,优化微波消解程序对花椒样品进行微波消解;测铅用载留液为2%HCl,测砷用载留液为5%HCl,还原剂硼氢化钾浓度为10 g/L,在此条件下测定铅和砷的标准曲线的相关系数分别为0.9992和0.9995,方法的加标回收率在95.00%~102.00%,相对标准偏差(RSD)1.26%~3.04%,方法检出限分别为0.1μg/L和0.02μg/L。该检测方法方便、快捷、准确且灵敏度高,为花椒制品的铅和砷含量测定提供了一种较好的方法。     

ICP-MS法测定动物肝脏中重金属元素的含量

以动物肝脏为研究对象,建立碰撞反应池-电感耦合等离子体质谱法分析动物肝脏中重金属含量的方法。样品经HNO_3-H_2O_2密闭高压消解后,以~(74)Ge、~(115)In、~(209)Bi、~(45)Sc为内标元素消除非质谱干扰,以氦气为碰撞反应气消除质谱干扰,采用电感耦合等离子体质谱法同时测定了动物肝脏中重金属铅、铊、镉、砷、铬和镍。试验结果表明:电感耦合等离子体质谱法检测6种重金属元素线性关系良好,相关系数均大于0.999。铅、铊、镉、砷、铬、镍的检出限分别为1.55、0.05、0.18、1.04、1.47、0.79μg/kg。方法用于分析标准物质,结果与标示值相符。     

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.     

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.     

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.     

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.     

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.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

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.