悬浮固化-分散液-液微萃取-气相色谱法测定蔬菜中6种拟除虫菊酯类农药

建立了QuEChERS(Quick,Easy,Cheap,Effective,Rugged and Safe的缩写)结合悬浮固化-分散液-液微萃取(DLLME-SFO)-气相色谱测定蔬菜中6种菊酯类农药残留的方法。待测样品用含1%乙酸的乙腈溶液提取,提取液经混合固相分散萃取净化后经DLLME-SFO浓缩,最后用气相色谱(ECD)进行检测。实验考察了QuEChERS方法中提取溶剂的影响,DLLME-SFO中萃取剂种类与体积,分散剂种类和体积,盐浓度等对萃取效率的影响,优化结果为以40μL十六烷为萃取剂,1000μL乙腈为分散剂,5mL水中NaCl的加入量为1.25g。结果表明,在黄瓜和番茄基质中6种菊酯类农药在5、10、50μg/kg 3个添加水平下农药的平均回收率为84.84%~111.59%,相对标准偏差(RSD)为0.48%~9.61%,方法的检出限(LOD,S/N≥3)和定量限(LOQ,S/N≥10)分别为0.07~0.58μg/kg和0.22~1.94μg/kg。该方法快速、简便、灵敏、重复性好,可用于蔬菜中拟除虫菊酯类农药的快速筛查测定。     

改进QuEChERS方法结合气相色谱串联质谱检测黄瓜中的邻苯二甲酸酯类

目的建立Fe_3O_4磁性纳米材料QuEChERS结合气相色谱串联质谱联用仪检测黄瓜中15种邻苯二甲酸酯类残留的方法。方法样品采用乙腈超声提取,经无水MgSO_4和NaCl盐析离心后,通过Fe_3O_4磁性纳米材料结合C_(18)和GCB吸附剂净化,采用气相色谱串联质谱MRM模式测定。结果在20~2000μg/kg范围内线性关系良好(r~2≥0.9985),检出限(S/N=3)为0.37~1.58μg/kg。进行了20、50和200μg/kg3个添加浓度的15种邻苯二甲酸酯类的回收率试验,回收率在84.9%~111.6%;RSD为0.41%~6.84%。结论该方法准确、灵敏,符合多残留检测和痕量分析的技术要求,适用黄瓜等蔬菜中邻苯二甲酸酯类残留的分析。     

高效液相色谱-串联质谱法测定牛奶和鸡肉中4种激素本底值

建立牛奶和鸡肉中4种激素(睾酮、甲基睾酮、孕酮、氢化可的松)本底值同时测定的高效液相色谱-串联质谱方法。样品经β-葡萄糖醛酸酶/芳香基硫酸酯酶水解,加入乙腈超声提取,正己烷除脂肪。采用ZORBAX SB-C18色谱柱分离,以0.1%甲酸溶液和甲醇为流动相梯度洗脱,分别在电喷雾离子源正、负离子模式下以多反应监测模式分段扫描同时检测,基质匹配外标法定量。结果表明,4种激素在相应的质量浓度范围内线性良好,相关系数均大于0.991;在牛奶中的检出限(RSN=3)和定量限(RSN=10)分别为0.02~0.10μg/kg和0.06~0.33μg/kg,在鸡肉中的检出限和定量限分别为0.03~0.12μg/kg和0.10~0.40μg/kg;在3个水平下的平均回收率为牛奶56.0%~132.8%,鸡肉79.6%~122.0%;相对标准偏差为牛奶1.8%~17.3%,鸡肉2.0%~18.1%。该方法简单、快速、准确,适用于对牛奶和鸡肉中4种激素进行快速筛查和本底值测定。     

QuEChERS/超高效液相色谱-串联质谱法测定茶叶中28种农药残留

建立了QuEChERS/超高效液相色谱-串联质谱（UPLC-MS/MS）测定绿茶中28种农药残留的分析方法。样品经1%乙酸乙腈提取,QuEChERS方法净化后进行UPLC-MS/MS测定。采用电喷雾离子源（ESI）,正离子模式扫描,多反应检测（MRM）模式采集,基质匹配工作曲线法定量。结果表明:28种目标化合物在各自浓度范围内线性良好,相关系数（r）为0.990~0.998,检出限（LOD,S/N≥3）为0.08~1.26 μg/kg,定量限（LOQ,S/N≥10）为0.28~4.20 μg/kg;在10、50、80 μg/kg 3个加标水平下平均回收率为72.5%~118.5%,相对标准偏差（n=6）为0.8%~16.3%。该方法简单、快速、重现性好、稳定性高,可满足茶叶中28种农药残留的检测要求。     

气相色谱-串联质谱法同时分析葡萄基质中 196种农药残留

目的建立同时分析葡萄基质中196种农药残留的气相色谱-串联质谱(GC-MS/MS)方法。方法葡萄样品经乙腈提取,QuEChERS方法净化,加入内标环氧七氯,采用GC-MS/MS在多反应监测模式(MRM)下分析,38 min内即可完成196种农药的分离,内标法定量。结果 196种农药在10~1000μg/L的浓度范围内线性关系良好,相关系数(r~2)大于0.99,各农药的检出限(S/N=3)为0.1~2.5μg/kg,各农药的定量限(S/N=10)为0.3~8.3μg/kg,在10.0μg/kg和50.0μg/kg 2个水平的添加浓度下,回收率在60.5%~126.2%之间,相对标准偏差0.2%~16.1%(n=6)。结论该方法准确可靠,灵敏度高,可用于葡萄基质中196种农药残留的同时检测。     

超高效液相色谱-串联质谱法测定鸡肉和鸡蛋中氯霉素和甲硝唑

目的建立超高效液相色谱-串联质谱法检测鸡肉和鸡蛋中的氯霉素和甲硝唑。方法鸡肉和鸡蛋样品经乙腈沉淀蛋白,乙酸乙酯和乙腈同时提取,Oasis MCX柱净化,以乙腈-水为流动相,采用ACQUITY BEH C18(2.1 mm×100 mm,1.7μm)色谱柱分离,分别以电喷雾负离子和正离子模式进行质谱测定,内标法定量。结果分别以鸡肉和鸡蛋为加标基质,三个加标水平下氯霉素和甲硝唑的平均回收率为96.3%~110.5%,相对标准偏差小于7.0%,氯霉素和甲硝唑的检出限(S/N=3)为0.1μg/kg,定量限(S/N=10)为0.3μg/kg。结论该方法操作快速简单、重现性好,可用于鸡肉和鸡蛋中氯霉素和甲硝唑的含量测定。     

超高效液相色谱-串联质谱法同时测定鸡肉中43种兽药残留

目的建立正负离子切换-超高效液相色谱-串联质谱法同时测定鸡肉中43种兽药残留量的分析方法。方法鸡肉样品经甲酸提取液涡旋提取,固相萃取净化, 10 mmol/L甲酸铵稀释, ACQUITY UPLC HSS T3色谱柱(2.1 mm×100 mm, 1.8μm)色谱柱分离,以0.05%甲酸溶液和0.05%乙腈进行梯度洗脱,正离子多反应监测39种兽药,负离子多反应检测4种兽药,外标法定量测定药物的含量。结果 43种兽药定量限为5μg/kg,标准曲线在0.4～100.0 ng/mL范围内均呈良好的线性关系。在空白鸡肉中3个不同添加水平下,平均回收率为60%～120%之间,变异系数为0.7%～12%。结论该方法准确、快速、灵敏、稳定,适合作为鸡肉中43种兽药残留量的测定。     

超高效液相色谱—四级杆/静电场轨道阱高分辨质谱法快速测定草鱼中7种激素

采用QuEChERS前处理技术,通过超高效液相色谱—四级杆/静电场轨道阱高分辨质谱(UPLC-Q/Orbitrap MS)建立了一种草鱼中7种激素药物残留的快速检测方法。结果表明:7种激素在1.0~100.0ng/mL浓度下具有良好的线性(R~2≥0.998),检出限为0.04~0.60μg/kg,定量限为0.2~1.8μg/kg,加标回收率为71.4%~106.9%,RSD(n=6)为2.4%~7.8%。7种激素呈基质抑制效应,通过空白基质匹配标准曲线补偿基质效应,获取准确结果,适用于大批量草鱼中雄激素、孕激素的快速检测。     

液相色谱-串联质谱法检测奶制品中9种β-受体阻断剂药物残留量

目的建立同时检测奶制品(牛奶、奶粉、奶酪)中9种β-受体阻断剂(β-blockers,BBS)残留的液相色谱-串联质谱方法。方法混合均匀的试样经β-葡糖醛苷酶/芳基硫酸酯酶水解,乙腈提取,硅藻土与Bond Elut分散固相萃取填料双重快速净化后,利用液相色谱-串联质谱法进行定性定量分析。结果 9种BBs在0.1~20.0μg/L线性范围内线性关系良好(r≥0.995);定量限(limit of quantity,LOQ,S/N≥10),均达到0.5μg/kg;3个添加水平(0.5、1.0和5.0μg/kg)下的回收率为89.5%~112.5%;相对标准偏差(relative standard deviation,RSD)为4.2%~11.5%。结论该方法快速、准确、灵敏,可用于奶制品样品中多种BBs残留的同时有效测定。     

液相色谱-串联质谱快速检测禽类组织中黄霉素A残留量

目的建立检测禽类组织(肌肉、脂肪、肝脏、肾脏)中黄霉素A残留的超快速液相色谱-四极杆/线性离子阱质谱方法。方法混合均匀的试样经10%氨化甲醇提取,乙腈沉降蛋白净化后,以0.3%甲酸-5%乙腈-水溶液和0.3%甲酸-5%水-乙腈为流动相,使用Agilent Poroshell 120 SB-C18(100 mm×2.1 mm,2.7μm)色谱柱超快速液相色谱分离,优化多反应检测(selected multiple reaction monitorin g,s MRM)模式检测,外标法定量。结果黄霉素A在20~200μg/L线性范围内线性关系良好(r≥0.995);黄霉素A定量限(limit of quantity,LOQ,S/N≥10)为10μg/kg;3个添加水平(10、20和100μg/kg)下的回收率为66.5%~89.4%;相对标准偏差(relative standard deviation,RSD)为4.7%~10.2%。结论该方法快速、准确、灵敏,可有效用于禽类组织中黄霉素A残留的测定。     

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.