高效液相色谱法测定番茄中腐霉利和异菌脲的 残留量

目的建立固相萃取-高效液相色谱法测定番茄中腐霉利和异菌脲的残留量。方法番茄样品用乙腈超声提取,加入氯化钠进行盐析脱水,提取液过Florisil柱净化,用正己烷/丙酮(90:10,V:V)淋洗液洗脱,洗脱液氮吹近干,甲醇定容后经ZORBAX Eclipse XDB-C_(18)(250 mm×4.6 mm,5μm)色谱柱进行分离,以乙腈/水(60:40,V:V)为流动相,流速为1.0 m L/min,采用二极管阵列检测器检测,检测波长为208 nm。结果在0.05~5.0 mg/L浓度范围内,腐霉利和异菌脲的质量浓度与其峰面积呈良好的线性关系(r~20.999),方法检出限均为0.025 mg/kg,在0.05、0.5和1.0 mg/kg 3个不同加标水平上,腐霉利和异菌脲的加标回收率为90.6%~102.4%,精密度为3.72%~6.55%。结论该方法操作简单、准确,可应用于番茄中腐霉利和异菌脲的检测。     

气相色谱-串联质谱法测定韭菜中的氯氟氰菊酯残留

目的建立气相色谱-串联质谱法(gas chromatography-tandem mass spectrometry,GC-MS/MS)测定韭菜中氯氟氰菊酯残留量的分析方法。方法将韭菜样品的乙腈提取物经石墨化碳黑/氨基混合型固相萃取柱净化、乙腈-甲苯(3:1,V:V)洗脱以及浓缩定容后进行检测。目标化合物经SLB-5MS(30 m×0.25 mm,0.25μm)色谱柱分离后,通过三重串联四级杆多反应监测模式对其进行定性定量分析。结果在添加水平为0.05~0.50mg/L(n=5)时,氯氟氰菊酯的回收率在81.7%~99.1%之间,相对标准差(RSD)在2.5%~8.7%之间。该方法的线性范围为0.05~0.50 mg/L,相关系数r~20.990,检出限为0.001 mg/kg,定量限为0.01 mg/kg。结论该方法能满足韭菜中氯氟氰菊酯残留检测的要求。     

柱前衍生反相高效液相色谱法测定 草本水杨梅叶中氨基酸含量

目的采用柱前衍生反相高效液相色谱法对草本水杨梅叶中氨基酸进行测定。方法样品以异硫氰酸苯酯(PITC)为衍生化试剂,与草本水杨梅叶中氨基酸柱前衍生,采用Ultimate Amino Acid氨基酸分析专用柱(4.6 mm×250 mm,5μm);流动相:A为乙腈-水(80:20,V:V),B为乙腈-三水合乙酸钠缓冲溶液(7:93,V:V,p H 6.5),梯度洗脱;柱温35℃,流速1.0 m L/min,检测波长为254 nm。结果 20种氨基酸在0.039~1.250 mmol/L内呈良好的线性关系(r20.9996)。20种游离氨基酸平均回收率在96.51%~108.06%之间,RSD在0.36%~2.08%之间(n=6);水解氨基酸平均回收率在95.29%~102.13%之间,RSD在0.85%~2.45%之间(n=6)。结论该方法可用于草本水杨梅中氨基酸的检测,其灵敏度高且准确,具有良好的重复性及稳定性。     

高效液相色谱法测定牛奶中硫氰酸钠含量

目的采用高效液相色谱法检测牛奶中硫氰酸钠含量。方法样品用5 m L乙腈沉淀蛋白质,上清液过C_(18)柱净化。以磷酸缓冲溶液(pH=7.0):乙腈(95:5,V:V)作为流动相,C18色谱柱(250 mm×4.6 mm,5μm)分析,柱温30℃±2℃,流速1.0 m L/min,以紫外检测器分析样品。结果该方法对牛奶中硫氰酸钠有较高的提取率,质量浓度范围在5~100 mg/L内线性较好(r~2=0.9995),检测限1.0 mg/kg,回收率90%。结论该方法具有预处理简单、灵敏度高的优点,满足对牛奶中硫氰酸钠含量的检测要求。     

高效液相色谱-串联质谱法测定水产品中喹乙醇残留量

目的 建立高效液相色谱-串联质谱联用法测定水产品中喹乙醇残留量的方法。方法 以罗非鱼为实验样品, 样品经乙腈提取、正己烷脱脂, 以乙腈-0.5 mmol乙酸铵甲酸溶液(10:90, V:V)为流动相进行等度洗脱、色谱柱Poroshell 120 EC-C18(50 mm×2.1 mm, 2.7 μm)分离, 在多反应监测(multiple reaction monitoring, MRM)模式下进行三重四极杆质谱检测。结果 喹乙醇在0.02~0.4 mg/kg范围内线性关系良好, 检出限为0.4 μg/kg, 加标回收率(n=6)为93.8%~97.0%, 相对标准偏差为2.10%~8.02%。结论 该方法简单、快速、灵敏度高、准确可靠, 可用于批量水产品样品喹乙醇残留量的测定。     

超高效液相色谱法测定甘蓝和橙子中的阿维菌素残留

本文研究建立了甘蓝和橙子中阿维菌素农药残留的超高效液相色谱紫外(UPLC-UV)检测方法。样品经乙腈提取,混合使用乙二胺-N-丙基硅烷(PSA)和C_(18)基质分散净化剂进行净化,采用ACQUITY UPLC BEH C_(18)色谱柱(2.1×100 mm,1.7μm),以乙腈:水(V/V=70:30)为流动相,流速0.25 m L/min,柱温:35℃,紫外检测波长:245 nm。阿维菌素在甘蓝和橙子样品中存在程度不同的基质效应,故采用空白基质匹配的校准曲线外标法定量。结果表明,阿维菌素在0.25~10 mg/L范围内具有良好的线性关系,相关系数均大于0.9999。在0.05~0.5 mg/kg范围内,平均添加回收率为83.0%~100.2%,相对标准偏差为1.17%~1.30%。阿维菌素在甘蓝和橙子中的检出限(LOD)分别为0.0109和0.0160 mg/kg。该方法操作简单、准确、灵敏,可用于甘蓝和橙子中阿维菌素的分析。     

高效液相色谱法测定马铃薯和土壤中的辛硫磷残留

目的建立高效液相色谱法测定马铃薯和土壤中辛硫磷残留的分析方法。方法样品经乙腈萃取,氨基固相萃取小柱净化,采用以色谱柱Agilent ZARBAX SB-C_(18) 柱(4.6 mm×250 mm,5μm)分离,甲醇/水(75:25,V:V)为流动相等度洗脱后紫外检测器检测,检测波长为280 nm。结果辛硫磷在0.05~10 mg/L浓度范围内线性关系良好(r~2=0.9990);最低检出限为0.02 mg/kg,辛硫磷在马铃薯块茎、植株和土壤中的添加水平为0.05~5.0 mg/kg时,添加回收率分别为92.3%~102.4%、98.5%~109.1%和89.7%~104.3%,相对标准偏差分别为1.0%~2.5%、1.4%~5.6%和1.4%~2.1%。结论该方法具有快速、准确、灵敏度高等特点,符合国家标准对食品中农药残留测定的要求。     

高效液相色谱法测定保健食品中三氯蔗糖的含量

目的建立一种保健食品中三氯蔗糖含量测定的高效液相色谱检测法。方法样品采用Rad pak C18色谱柱(4.6 mm×250 mm,5μm)进行分离,以1.0 m L/min乙腈:水(V:V=15:85)为流动相,最后用高效液相色谱法(HPLC)-示差折光仪为检测器进行测定,外标法定量分析。结果高效液相色谱法在0.482~2.892 mg/m L浓度范围,三氯蔗糖的浓度和峰面积的线性良好,相关系数为0.999(r0.99),该方法的检出限和定量限分别为19.58 mg/g和65.27 mg/g,在不同的添加水平下,该方法的回收率范围为95.0%~95.6%,相对标准偏差为0.3%(n=9)。结论高效液相色谱法灵敏度、准确度均较高,适用于保健食品中三氯蔗糖的含量测定。     

高效液相色谱法检测蔬菜中的吡虫啉残留

本文建立了一种果蔬中吡虫啉农药残留的高效液相色谱检测方法。样品经乙腈提取、盐析、LC-NH2小柱净化,采用高效液相色谱仪-紫外检测器进行测定,色谱柱:Waters Symmetry Shield C18(4.6×250 mm,5μm);柱温:30.0℃;检测波长:275 nm;流动相:甲醇:水:乙腈=55:25:20(体积比);流速:0.8 mL/min;进样量:10.0μL。吡虫啉在0.1 mg/L至1.0 mg/L的添加范围内线性良好,线性关系系数r为0.9925;添加水平为0.05~0.20 mg/kg时,西红柿样品的平均回收率为95.4%~106.8%,相对标准偏差为2.66%~7.99%。结果表明该方法具有快速、灵敏、准确等优点,适合蔬菜中吡虫啉农药残留的测定。     

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。     

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.