液液萃取-气相色谱法测定黄酒中β-苯乙醇含量

建立黄酒中β-苯乙醇的液-液萃取-气相色谱检测方法,为炮制辅料黄酒的质量控制研究提供参考。用碳酸钠饱和的15%乙醇溶液与乙酸乙酯1︰1 (V/V)混合均匀,超声分层,取上层澄清液作为萃取剂;采用气相色谱法,Agilent HP-5色谱柱(30 m×0.32 mm×0.25μm), FID检测器,进样口温度230℃,检测器温度250℃,柱温程序升温为:初始温度120℃,恒温2 min,以25℃/min升温至210℃,恒温10 min,柱流量1 mL/min,进样量1.0μL,内标物4-(4-甲氧苯基)-2-丁酮。结果表明,β-苯乙醇在4.86～243.02 mg/L范围内线性关系良好(r=0.999 9),精密度试验RSD值为0.20%,重复性试验RSD值为4.66%, 3种加标浓度的回收率在94.28%～102.57%之间,检出限为0.08 mg/L,定量限为0.20mg/L。该方法具有简单、可靠、结果准确等优点,同时有效降低黄酒中糖分、色素等基质对气相色谱系统的污染,减少水分对毛细管色谱柱的危害,可用于辅料黄酒中β-苯乙醇含量检测及质量控制。     

盐辅助分散液液微萃取-气相色谱-串联质谱法检测葡萄酒中的氨基甲酸乙酯

目的建立了盐辅助分散液液微萃取(salt-assisted dispersive liquid-liquid microextraction,SADLLME),稳定同位素稀释,气相色谱-串联质谱法(gas chromatography-tandem mass spectrometry,GC-MS/MS)检测葡萄酒中氨基甲酸乙酯(ethyl carbamate,EC)的方法。方法取30 mL葡萄酒于50 mL离心管中,加入浓度为10μg/mL的EC-d5溶液100μL和硫酸钠3 g,震荡溶解,注射针快速打入700μL二氯甲烷,震荡1 min,离心,取下层有机相,经DB-INNWAX UI色谱柱(30 m×0.25 mm,0.25μm)分离,多重反应监测方式进行质谱检测。结果方法在验证浓度范围内(5～1500 ng/mL),线性良好,r~2=0.9988,检出限为0.73μg/L,定量限为2.18μg/L,回收率为91.5%～97.8%,相对标准偏差为2.55%～5.26%。对市场上3个品牌红葡萄酒进行检测,EC含量为6.82～15.3μg/L。结论该方法样品处理简便、快速,相对绿色,定性、定量可靠,能够满足葡萄酒中EC风险监测的需要。     

GC-MS/MS测定不同食品中氨基甲酸甲酯及氨基甲酸乙酯的含量

建立内标法同时测定固体半固体及液体基质中氨基甲酸甲酯及氨基甲酸乙酯含量的气相-质谱/质谱(Gaschromatography-Mass/Mass,GC-MS/MS)方法。以D5-氨基甲酸乙酯为内标,采用GC-MS/MS多反应监测模式(Multiple Reaction Monitoring,MRM模式);毛细管色谱柱:DB-INNOWAX,30 m×0.25 mm(内径)×0.25μm(膜厚);进样方式:脉冲不分流;进样量:1μL;柱温:80℃保持2 min,以10℃/min至180℃保持3 min,240℃后运行6 min;流速1.0 mL/min。氨基甲酸甲酯在20 ng/mL~1 000 ng/mL,氨基甲酸乙酯在10 ng/mL~500 ng/mL范围内线性关系良好。相关系数分别为0.998 7和0.999 9。液体基质平均回收率为78.4%及100.20%。固体及半固体基质平均回收率为62.48%及100.49%,检出限分别为6μg/kg及3μg/kg。本方法灵敏度高,专属性强,稳定性好,准确度高。     

超高效液相色谱法快速测定饮料中13种常见的食品添加剂

目的建立超高效液相色谱法(ultra performance liquid chromatography,UPLC)测定水果茶饮料中常见的13种防腐剂、甜味剂和着色剂的分析方法。方法样品经超声加热除去二氧化碳或乙醇后稀释、离心、过滤后直接进样,采用Agilent ZORBAX Eclipse Plus C_(18)(50 mm×2.1 mm,1.8μm)色谱柱分离,以甲醇-乙酸铵(0.02 mol/L)为流动相进行梯度洗脱,柱温28℃,流速0.5 mL/min,采用二极管阵列检测器切换波长分析,外标法定量。结果 13种待测成分在6 min内良好分离,质量浓度在0.05～10μg/mL范围内线性良好,相关系数r~2均大于0.999;定量限为0.010～0.025μg/mL;平均加标回收率在92.1%～101.0%之间;重复性和精密度RSD(n=6)在5.0%以内。结论该方法快速、准确,适合用于饮料中13种防腐剂、甜味剂、合成着色剂定性、定量测定。     

GC法测定藿胆分散片中百秋李醇的含量

目的建立毛细管气相色谱法(GC)测定藿胆分散片中百秋李醇含量的方法。方法样品经超声提取、离心过滤后采用GC测定。色谱条件:色谱柱为PEG-20M为固定相的毛细管柱(30 m×0.25 mm,0.5μm);柱温采用程序升温,初始温度120℃,保持5 min,再以10℃/min的速率升温至160℃,保持11 min;进样口温度260℃;FID检测器,温度280℃;载气为氮气,流速3.69 m L/min,分流比30:1;进样量1μL。以正十八烷为内标物。结果百秋李醇在5.64×10-3~2.256×10-2 mg/m L浓度范围内呈良好的线性关系(Y=175.57X-0.036,r=0.9990),平均回收率为101.61%(n=6)。结论该方法简便、灵敏度较高、重现性良好,可作为藿胆分散片质量控制的主要方法。     

不同方法提取罗汉果化学成分的GC-MS比较分析

采用不同方法提取永福罗汉果果实中的挥发性化学成分,应用气相色谱-质谱计算机联用技术全面分析其化学成分。分别采用超声波浸取法、匀浆萃取法、水蒸汽同时蒸馏萃取法从罗汉果中提取挥发性成分,并应用GC-MS对其化学成分进行分离、分析和鉴定,同时采用峰面积归一化法测定相对百分含量。色谱条件:色谱柱为Elite-5MS毛细管柱(30 m×0.25 mm,0.25μm),载气为氦气(He),分流比30∶1,流速0.8 mL/min,进样口温度230℃,检测器温度280℃,升温程序:起始温度50℃,保持5 min,4℃/min升至80℃,接着8℃/min升至230℃,保持12 min,然后以12℃/min升至250℃,保持2 min。采用超声浸取法共定性了21个化合物,占总成分的89.388%;匀浆萃取法共定性了25个化合物,占总成分的91.937%;水蒸汽同时蒸馏萃取法共定性了67个化合物,占总成分的92.937%。3种方法提取的化合物在成分和含量上都存在一些差异,其中超声浸取和匀浆萃取提取的成分差异不大,而水蒸汽同时蒸馏萃取提取的成分与前两种差异较大。     

冷冻液液革取-高效液相色谱法測定可乐中的4-甲基咪唑

建立了一种冷冻液液萃取-高效液相色谱法测定可乐中4-甲基咪唑的方法。样品在碱性条件下,以乙腈作为萃取溶剂,经涡旋后,在-23℃下冷冻净化;取上清液氮气吹干,用蒸馏水定容,然后利用高效液相色谱仪在UV 210nm处检测。结果表明,该方法4-甲基咪唑的检出限和定量限分别为0.033μg/mL和0.100μg/mL;在浓度0.25μg/mL¹00μg/mL范围内,线性相关系数为0.9999;样品在1.5μg/mL、3.0μg/mL、6.0μg/mL 3个水平上,加标回收率平均值均大于85%,相对标准偏差均不超过5%(n=7),具有良好的准确度和重复性。与常规液液萃取相比,该前处理方法操作简单,有机试剂用量少,适合一次处理多个样品,具有一定的推广价值。     

HPLC-ELSD测定灵芝及其孢子粉中胆碱质量分数

建立了一种运用高效液相色谱-蒸发光散射检测器(HPLC-ELSD)测定灵芝及其孢子粉中胆碱含量的方法。实验采用Agilent公司ZORBAX 300-SCX阳离子交换色谱柱(4.6 mm×250mm,5μm),柱温30℃,流动相为乙腈-乙酸铵溶液,等度洗脱,流量为1.0 mL/min,进样量为10μL;蒸发光散射检测器检测,漂移管温度为60℃,喷雾器为模式加热,雾化气为净化空气,气体压力为172.4 kPa。研究结果表明,该方法精密度、重复性、稳定性和回收率均良好,在6.25~200μg/mL范围内胆碱具有良好的线性关系,检出限为6μg/mL,定量限为12μg/mL,是一种快速高效检测灵芝及其孢子粉中胆碱的方法。     

分散液相微萃取-液相色谱法测定奶瓶中的双酚A

建立了分散液相微萃取提取婴儿奶瓶中溶出痕量双酚A(BPA)的方法,并用高效液相色谱测定了其含量。奶瓶浸泡液用0.5 mL氯仿作萃取剂,0.5 mL甲醇作分散剂,以3 500 r/min离心10 min,吸取萃取剂20μL,进样,采用高效液相色谱法(HPLC)测定BPA的含量。色谱柱为Inertsil C18柱(5μm,4.6×150 mm),流动相为甲醇∶水(V∶V)=70∶30,流速为0.8 mL/min,检测波长为280 nm。该方法 BPA在0.05 mg/L~0.25 mg/L范围内线性关系良好(R=0.999 7),BPA检出限(S/N=3)为0.50μg/L。该法用于婴儿奶瓶中BPA含量的检测,测得婴儿奶瓶中双酚A的含量范围在0~18.93μg/L,平均加标回收率为96.44%,RSD为4.57%(n=4)。方法结果满意,可适用于婴儿奶瓶、矿泉水等食品和饮料容器中溶出BPA的含量测定。     

香蕉酒香气成分的萃取及其气相色谱检测条件的优化

目的 优化检测香蕉酒香气成分的气相色谱条件,筛选出最优色谱条件。方法 使用正交设计试验法设计试验方案,考察了载气流速、起始温度和升温程序等七个因素三个水平的参数对分离效果的影响,引入综合评价函数Q作为分离效果评价指标,并对函数中的权重系数γ的不同取值进行数据处理分析。结果γ取值为10最合理,得到的最优色谱条件为：毛细管色谱柱（固定相SH-Rtx-5,30m × 0.25mm,0.25μm）,载气N2的流速为1 mL/min,H2流速为30 mL/min,空气流速为200 mL/min,尾吹气流速为24 mL/min,进样量为1μL,分流比为10︰1,进样口温度为230℃,初始柱温为50℃,保持5min,然后以8℃/min 程序升温至114 ℃,继续以10℃/min程序升温至220℃,并保持25min,氢火焰离子化检测器的温度为250℃。其验证试验结果与推论一致。结论 得到的最优气相色谱条件对香蕉酒香气成分的分离效果好,为下一步研究提供了有益的参考。     

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.