固相萃取-气质联用法测定水产品中扑草净

建立检测水产品中扑草净残留量的固相萃取-气相色谱质谱联用法。样品用乙腈提取,浓缩后经PSA固相萃取柱净化,由气质联用仪选择离子监测模式下测定。该方法条件下扑草净在2.5μg/L~40μg/L浓度范围内线性良好,对空白样品分别添加2、10、20μg/kg扑草净标准溶液,平均回收率在80%~98%,RSD小于10%,检出限为0.5μg/kg。     

ASE-GPC-LC/MS/MS联用检测贝类样品中扑草净的残留

建立了ASE(快速溶剂提取)、GPC(凝胶渗透色谱仪)、(液相色谱-质谱联用)LC/MS/MS法检测贝类样品中扑草净残留量的分析方法。本实验采用乙腈经ASE上机提取,凝胶渗透色谱仪净化,最后通过液相色谱-串联质谱进行定量检测。实验结果表明:扑草净在线性范围为0.25~40μg/kg时,线性关系良好(R2=0.9999),回收率为90.0%~105.4%,相对标准偏差2.9%~5.3%。     

凝胶渗透色谱净化-超高效液相色谱-串联质谱法测定海带中扑草净残留量

目的 建立凝胶渗透色谱(gel permeation chromatography, GPC)净化-超高效液相色谱-串联质谱(ultra performance liquid chromatography-tandem mass spectrometry, UPLC-MS/MS)法测定海带中扑草净残留量的分析方法。方法 样品用乙腈超声提取, 经凝胶渗透色谱净化, 收集15~35 min的流出液并进行浓缩, 通过超高效液相色谱柱分离后进行质谱检测。结果 称样量为2 g时, 最佳提取条件为10 mL乙腈超声提取时间10 min; 在添加量为0.05~2.66 μg/kg范围时, 扑草净平均回收率为100.1%~102.1%, 相对标准偏差(relative standard deviation, RSD)为1.6%~2.6% (n=6); 方法检出限为0.15 μg/kg; 并将GPC与HLB、Carb-NH2固相萃取进行净化效果比较, 结果表明GPC净化更适用于海带中扑草净的净化。结论 该方法简便、快速、灵敏度高、重复性好, 可用于测定海藻类样品的扑草净残留。     

高效液相色谱串联质谱法测定红糖中5-羟甲基糠醛

建立了红糖中5-羟甲基糠醛的高效液相色谱串联质谱检测方法。红糖样品经甲醇-水(V/V=5/95)充分溶解提取,经HLB柱富集净化,氮吹干洗脱液,用乙腈-水(V/V=1/9)复溶,供高效液相色谱串联质谱仪检测。以甲醇和水为流动相梯度洗脱,用Phenomenex Luma Omega C18柱(1.6μm,100 mm×2.1 mm)分离,电喷雾正离子模式(ESI+)扫描,多反应监测模式(MRM)采集数据,外标法定量。该方法在0.5~50.0μg/L范围内线性关系良好(r²=0.9999),检出限为0.44μg/kg,定量限为1.47μg/kg。在2.0、5.0、10.0μg/kg的加标水平下,5-羟甲基糠醛的平均回收率为86.3%~97.8%,相对标准偏差为2.1%~5.0%(n=6)。本方法操作简单、灵敏度高、准确度和净化效果好,适用于红糖中5-羟甲基糠醛的残留量测定。     

食品中黄曲霉毒素B_1的液相色谱-串联质谱测定法

建立了食品中黄曲霉毒素B1残留量的超高效液相色谱-串联质谱的检测方法。样品经乙腈+水(84+16)提取后,经多功能净化柱净化,超高效液相色谱-串联质谱法检测。本方法定量限为1μg/kg,线性范围为1~20 ng/mL;在黄曲霉毒素B1添加水平为1~10μg/kg时,在玉米样品中的回收率为95%~105%;在酱油样品中的回收率为96%~106%。     

高效液相色谱串联质谱法测定食糖中4-甲基咪唑和2-甲基咪唑

建立了食糖中4-甲基咪唑和2-甲基咪唑的高效液相色谱串联质谱检测方法。食糖样品经乙醇充分提取,经PCX柱富集净化,氮吹干洗脱液,用乙腈-水(V/V=9/1)复溶,供高效液相色谱串联质谱仪检测。以乙腈和5mmol/L乙酸铵水溶液(含0.1%甲酸)为流动相梯度洗脱,用ACQUITYUPLCBEN HILIC柱(1.7μm,100 mm×2.1 mm)分离,电喷雾正离子模式(ESI+)扫描,多反应监测模式(MRM)采集数据,外标法定量。结果显示,该方法在0.5～20.0μg/L浓度范围内线性关系良好,4-甲基咪唑和2-甲基咪唑的相关系数分别为0.9999和0.9994,检出限分别为0.07和1.07μg/kg,定量限分别为0.24和3.57μg/kg。在5.0、10.0、15.0μg/kg的加标水平下,4-甲基咪唑和2-甲基咪唑的平均回收率在81.2%～96.9%之间,相对标准偏差在1.4%～5.1%(n=6)之间。本方法操作简单,结果准确可靠、灵敏度高,适用于食糖中4-甲基咪唑和2-甲基咪唑的残留量测定。     

固相萃取-高效液相色谱法检测葡萄中氯吡脲的研究

利用固相萃取-高效液相色谱(SPE-HPLC)分离测定葡萄中氯吡脲的残留量。样品匀浆经乙腈提取,固相萃取柱净化后,在流动相为甲醇-纯水(体积比为63:37)、紫外检测波长为260nm的色谱条件下进行分离检测。实验结果表明:经筛选碱性氧化铝柱对样品的净化效果较好,氯吡脲在0.01～1.00μg/mL范围内线性关系良好,相关系数r=0.9999,最低检出浓度为0.0001mg/kg。试样在0.004、0.010、0.050mg/kg3个添加水平下的平均回收率在94.38%～99.33%之间,相对标准偏差(RSD)在1.67%~3.62%之间。利用此方法对市售4个品种葡萄中氯吡脲的残留量进行检测,最终残留均符合标准。     

超高效液相色谱-串联质谱法测定猪肉中巴氯芬的残留

目的建立超高效液相色谱-串联质谱法测定猪肉中巴氯芬残留量的方法。方法样品采用0.1moL/L盐酸-甲醇溶液(20:80,V:V)提取,混合型强阳离子交换柱(MCX)净化,经C_(18)反相色谱柱分离后,正离子扫描,多反应监测模式检测巴氯芬,基质标曲定量。结果该方法在1～500 ng/mL浓度范围内线性良好, r~2=1,检出限为1μg/kg,定量限为5μg/kg,回收率为75.28%～77.86%,精密度RSD10%。结论该方法灵敏度高、特异性强,适用于猪肉中巴氯芬残留量的分析。     

超高效液相色谱-串联质谱法测定猪肉中肾上腺素残留量

建立了猪肉中肾上腺素残留量的超高效液相色谱-串联质谱(UPLC-MS/MS)的检测方法。样品经乙腈+甲醇(95+5)提取,C_(18)色谱柱分离,超高效液相色谱-串联质谱仪检测。本方法定量限为10μg/kg,线性范围为5～500ng/mL。样品加标回收率为75%～98%,相对标准偏差为4.8%～7.9%,方法简便快速、灵敏度高,为猪肉中肾上腺素残留量测定提供了新的方法。     

固相萃取-LC-MS/MS同时测定牛奶中7种β_2-受体激动剂

建立了牛奶中7种β2-受体激动剂残留量超高效液相色谱/串联质谱的分析方法。牛奶样品经40%甲醇溶液提取、乙酸锌溶液蛋白沉淀、HLB固相萃取柱净化后,以C_18为分析色谱柱,甲醇-0.1%甲酸溶液作为流动相进行梯度洗脱分离,采用多反应监测(MRM)模式测定。结果表明,7种β_2-受体激动剂在0.04μg/kg~4μg/kg的浓度范围内呈线性,其相关系数r~2大于0.998,定量限在0.01μg/kg~0.04μg/kg,加标回收率为66.8%~99.2%,相对标准偏差(RSD)范围为2.0%~15.8%。本方法灵敏度高,准确度好,对实际样品进行了测试分析,均获得了满意的结果。     

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.     

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.     

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.     

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.