食品塑料包装中18种多环芳烃的气相色谱-质谱联用检测方法研究

建立了一种气相色谱-质谱联用法测定食品塑料包装中18种多环芳烃的检测方法,样品经超声提取和硅胶固相萃取柱净化,气相色谱-质谱联用仪测定18种多环芳烃的含量。对提取溶剂、提取温度、提取时间进行选择优化,18种多环芳烃的浓度在(0.1~5.0)mg/L范围内与色谱峰面积呈良好的线性,线性相关系数r~20.995,方法检出限为(0.010~0.056)mg/kg,在0.5、1.0、5.0 mg/kg添加水平下平均回收率分别为71.3%~84.4%,80.3%~91.5%,80.0%~95.0%,相对标准偏差分别为3.03%~7.78%、2.11%~5.70%、1.55%~4.75%,该方法应用于实际样品测定,效果满意。     

气相色谱-质谱法测定革材中DMF、DMAC和NMP残留量(续)北大核心

建立了革材中N,N-二甲基甲酰胺(DMF)、N,N-二甲基乙酰胺(DMAC)和N-甲基吡咯烷酮(NMP)3种有害溶剂残留量的气相色谱-质谱(GC-MS)同时测定方法。以甲醇为萃取剂,超声萃取后滤膜净化,再用GC-MS测试分析,外标法定量。在浓度0.1~20mg/L范围内3种目标物的线性关系良好,方法检出限在1.2~1.6mg/kg之间。以空白样品为基质,进行4个添加水平6次平行试验,结果表明:3种目标物的平均回收率均在85%~105%范围内,相对标准偏差(RSD)均小于6%。采用该方法测试了20个实际革材样品中DMF、DMAC和NMP残留量,其中皮革样品检出分别为75.2~539.2mg/kg、4.3~44.4mg/kg和5.0~25.7mg/kg;合成革样品检出分别为82.2~342.5mg/kg、8.6~78.8mg/kg和6.9~7.2mg/kg。     

气相色谱-质谱法测定革材中DMF、DMAC和NMP残留量北大核心

建立了革材中N,N-二甲基甲酰胺(DMF)、N,N-二甲基乙酰胺(DMAC)和N-甲基吡咯烷酮(NMP)3种有害溶剂残留量的气相色谱-质谱(GC-MS)同时测定方法。以甲醇为萃取剂,超声萃取后滤膜净化,再用GC-MS测试分析,外标法定量。在浓度0.1~20mg/L范围内3种目标物的线性关系良好,方法检出限在1.2~1.6mg/kg之间。以空白样品为基质,进行4个添加水平6次平行试验,结果表明:3种目标物的平均回收率均在85%~105%范围内,相对标准偏差(RSD)均小于6%。采用该方法测试了20个实际革材样品中DMF、DMAC和NMP残留量,其中皮革样品检出分别为75.2~539.2mg/kg、4.3~44.4mg/kg和5.0~25.7mg/kg;合成革样品检出分别为82.2~342.5mg/kg、8.6~78.8mg/kg和6.9~7.2mg/kg。     

气相色谱-质谱法测定革材中DMF、DMAC和NMP残留量(续)

建立了革材中N,N-二甲基甲酰胺(DMF)、N,N-二甲基乙酰胺(DMAC)和N-甲基吡咯烷酮(NMP)3种有害溶剂残留量的气相色谱-质谱(GC-MS)同时测定方法。以甲醇为萃取剂,超声萃取后滤膜净化,再用GC-MS测试分析,外标法定量。在浓度0.1~20mg/L范围内3种目标物的线性关系良好,方法检出限在1.2~1.6mg/kg之间。以空白样品为基质,进行4个添加水平6次平行试验,结果表明:3种目标物的平均回收率均在85%~105%范围内,相对标准偏差(RSD)均小于6%。采用该方法测试了20个实际革材样品中DMF、DMAC和NMP残留量,其中皮革样品检出分别为75.2~539.2mg/kg、4.3~44.4mg/kg和5.0~25.7mg/kg;合成革样品检出分别为82.2~342.5mg/kg、8.6~78.8mg/kg和6.9~7.2mg/kg。     

气相色谱-质谱法测定革材中DMF、DMAC和NMP残留量

建立了革材中N,N-二甲基甲酰胺(DMF)、N,N-二甲基乙酰胺(DMAC)和N-甲基吡咯烷酮(NMP)3种有害溶剂残留量的气相色谱-质谱(GC-MS)同时测定方法。以甲醇为萃取剂,超声萃取后滤膜净化,再用GC-MS测试分析,外标法定量。在浓度0.1~20mg/L范围内3种目标物的线性关系良好,方法检出限在1.2~1.6mg/kg之间。以空白样品为基质,进行4个添加水平6次平行试验,结果表明:3种目标物的平均回收率均在85%~105%范围内,相对标准偏差(RSD)均小于6%。采用该方法测试了20个实际革材样品中DMF、DMAC和NMP残留量,其中皮革样品检出分别为75.2~539.2mg/kg、4.3~44.4mg/kg和5.0~25.7mg/kg;合成革样品检出分别为82.2~342.5mg/kg、8.6~78.8mg/kg和6.9~7.2mg/kg。     

分光光度法测定不同食品基质中亚硝酸盐含量

目的建立测定不同食品基质中亚硝酸盐含量的分光光度法。方法取适量样品,按不同基质进行提取和净化,用分光光度法测定亚硝酸盐含量(以亚硝酸钠计)。结果方法检出限:液态乳和发酵乳中为0.02 mg/kg,其他样品中为0.2 mg/kg。淀粉类样品在添加浓度1.0~5.0 mg/kg范围内,回收率为77.6%~113%,RSD为1.9%~13.4%;肉制品类样品在添加浓度2.0~10.0 mg/kg范围内,回收率为77.5%~111.5%,RSD为2.1%~7.8%;腌菜类样品在添加浓度2.0~10.0 mg/kg范围内,回收率为58.5%~78.1%,RSD为4.0%~12.5%;液态乳、发酵乳类样品在添加浓度0.2~1.0 mg/kg范围内,回收率为81.5%~98.8%,RSD为1.4%~8.1%。结论该方法对不同食品基质样品的前处理方法进行了优化,干扰少,准确度、灵敏度高,能满足各类食品中亚硝酸盐的测定。     

分散固相萃取-气相色谱法同时检测食品塑料 包装材料中7种烷基胺

目的建立了分散固相萃取-气相色谱法(dispersive solid-phase extraction-gas chromatography,dSPE-GC)同时测定食品塑料包装材料中7种有机胺类物质的残留量。方法样品经二氯甲烷超声萃取15 min,采用25 mg C_(18)、25 mg PSA和10 mg MWCNT固相萃取剂对提取液进行净化,采用DB-1701色谱柱进行分离并进行气相色谱测定。同时对固相萃取剂的种类和用量、色谱柱等条件进行了优化。结果 7种烷基胺类物质在1.0~100 mg/L浓度范围内线性关系良好,相关系数为0.9937~0.9996;方法检出限为2.6~5.0 mg/kg;添加水平为5.0、10.0和50 mg/kg时,7种目标物的平均回收率为81.9%~107%,日内精密度(n=6)为1.9%~5.3%;日间精密度(n=5)为4.5%~9.1%。对市售10个塑料包装材料进行测定,其中1个样品检出青霉胺,含量为9.1 mg/kg。结论本方法快速准确,可适用于食品塑料包装材料中烷基胺类物质的测定。     

大体积进样法测定白酒中7种邻苯二甲酸酯

采用高效液相色谱大体积进样法测定白酒中7种邻苯二甲酸酯类物质。通过添加乙醇或水使试样基体的酒精度调整至38%vol,然后直接进样1 000μL,使用HC-C18色谱柱,以70%乙腈水溶液和纯乙腈为流动相梯度洗脱,以紫外检测器检测(波长225 nm)。DAP、BBP、DBP、DEHP和DNOP等5种目标物在0.02~2 mg/L浓度范围内具有良好的线性响应关系,检出限(S/N=3)为0.005~0.007 mg/kg;DINP、DIDP等2种目标物在0.1~4 mg/L浓度范围内具有良好的线性响应关系,检出限(S/N=3)为0.04~0.05 mg/kg。在高、中、低三种不同加标水平下,各目标物的回收率在87%~106%之间,相对标准偏差(n=6)均不超过7%。     

液相色谱-三重四级杆质谱法测定苹果中 腈苯唑农药残留

目的 为加强我国苹果中腈苯唑农药残留的监控,保护我国苹果在国际贸易中的合理地位,建立了苹果中腈苯唑的液相色谱-三重四极杆质谱(UPLC-MS/MS)测定方法。方法 样品经乙腈提取,超高效液相色谱-串联质谱下进行测定。结果 目标物在0.005~0.50 mg/L范围内成线性,相关系数r>0.99,空白样品中分析物在添加浓度为0.01、0.02、0.05 mg/kg时,平均回收率为89.6%~93.0%,相对标准偏差为2.4%~7.9%,定量限为0.01 mg/kg。结论 本方法操作简便、灵敏度高、准确度好,能满足农残检测分析的要求。     

液相色谱-三重四级杆质谱法测定苹果中腈苯唑农药残留

目的为加强我国苹果中腈苯唑农药残留的监控,保护我国苹果在国际贸易中的合理地位,建立了苹果中腈苯唑的液相色谱-三重四级杆质谱(UPL-C-MS/MS)测定方法。方法样品经乙腈提取,超高效液相色谱.串联质谱下进行测定。结果目标物在0.005~0.50 mg/L范围内成线性,相关系数r0.99,空白样品中分析物在添加浓度为0.01、0.02、0.05 mg/kg时,平均回收率为89.6%~93.0%,相对标准偏差为2.4%~7.9%,定量限为0.01 mg/kg。结论本方法操作简便、灵敏度高、准确度好,能满足农残检测分析的要求。     

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.     

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.     

Analysis on Economic Indicators from 62 Enterprises in Printing Machinery Industry in Q1 2014

Operation of printing machine industry was still unsatisfactory in the first quarter of 2014.Analysis on operation of printing machine industry.a.Market demand was not strong;sales of product undulated and declined.According to the statistics,the total industrial output value fell by 19.28% in the first quarter of 2014 than the average quarter value in 2013; industrial added value decreased by 4.16%; sales revenue dropped by 22.83%. h. Business operation of enterprises was in poor condition. c. R＆D of new products is an important transformation guarantee for enterprises. d. To take self explore new ways upgrading advantages,and explore new ways.