HPLC测定撑篙竹竹叶中异牡荆苷的含量

建立HPLC测定撑篙竹竹叶中异牡荆苷的含量。采用反相高效液相色谱法,色谱柱:Z0RBAX SB-C18(2.1 mm×100 mm,3.6μm),甲醇(A)-0.1%冰醋酸水溶液(B)为流动相,梯度洗脱(0 min~3 min,85%~70%B;3 min~6 min,70%~55%B;6 min~9 min,55%~35%B;9 min~12 min,35%~35%B;12 min~15 min,35%~70%B;15 min~18 min,70%~85%B),流速0.6 mL/min,检测波长340 nm,柱温30℃。异牡荆苷在1.733 1μg/mL~10.832 0μg/mL呈良好的线性关系(r=0.999 6),平均回收率为98.01%,RSD1.02%,试验测得异牡荆苷的含量为2.928 5 mg/g。     

高效液相色谱法测定奶粉中酪蛋白磷酸肽的含量

采用高效液相色谱(HPLC)法对奶粉中酪蛋白磷酸肽(CPP)含量进行测定,样品通过调节p H、超声提取、离心分离和浓缩等方式进行前处理,C18柱分离,流动相为乙腈+0.1%TFA和水+0.1%TFA,梯度洗脱,检测波长215 nm,以保留时间定性,外标法定量,并与钡-乙醇沉淀法测定的结果进行对比。结果表明,HPLC检测CPP与杂质分离效果良好,线性范围0.1~2.0 mg/m L,加标0.1%~0.3%,回收率97.59%~100.00%;并测定多个厂家奶粉中的微量CPP,与实际添加量较接近,适用性良好,表明该方法简便,准确度和灵敏度高,其检测限为15.34 mg/kg、定量限为51.14mg/kg,适用于奶粉中微量CPP含量检测。钡-乙醇沉淀法测定奶粉中CPP含量结果与实际差别太大,不适用于奶粉中CPP含量的测定。     

LC-MS法测定钙片中酪蛋白磷酸肽含量

用液相色谱-质谱联用法,以选择离子模式(SIM)检测钙片中酪蛋白磷酸肽(CPP)含量。结果表明,该法前处理简便,专属性好,灵敏度高,检出限为1μg/ml,在1～100μg/ml范围内线性回归方程为y=3074.6x+684.6,R2=0.999,回收率为96%～104%,可用于测定钙片中CPP的含量,也可用于其它钙强化剂中添加CPP的检测。     

HPLC测定阿昔莫司缓释片的含量

目的建立采用高效液相色谱(HPLC)测定阿昔莫司缓释片含量的方法。方法采用Agilent TC-C_(18)色谱柱(4.6 mm×150 mm,5μm),流动相为0.13%庚烷磺酸钠溶液-甲醇-冰醋酸(85:15:1),检测波长为273 nm,流速为1 mL/min。结果阿昔莫司在19.63~98.16μg/mL范围内线性关系良好(r=0.9999),平均回收率为99.61%,RSD为0.60%。结论本方法准确、高效,可用于阿昔莫司缓释片质量控制。     

高效液相色谱法同时测定泡蒜中的有机酸

建立了HPLC同时测定泡蒜中有机酸含量的分析方法。通过色谱条件的优化,确定了泡蒜中有机酸含量测定的最佳色谱条件:色谱柱为Agilent ZORBAX SB-Aq(4.6mm×250mm,5μm),流动相为0.01mol/L磷酸氢二铵(pH 2.5)和甲醇溶液,流速0.6mL/min,柱温30℃,检测波长220nm。在此条件下,酒石酸等6种有机酸可得到很好的分离和测定。该方法各种酸的线性范围为0.001~1.000mg/mL,标准曲线相关系数均在0.9999以上,精密度检测RSD为0.07%~0.36%(n=5),重复性检测RSD为0.43%~4.64%(n=5),回收率为96.25%~105.57%。该方法简单、快捷、准确、重复性好,可应用于泡蒜成品中有机酸的同时测定。     

红葡萄酒中合成色素的测定研究

建立了HPLC测定红葡萄酒中色素柠檬黄、苋菜红、日落黄、胭脂红含量的方法,采用色谱柱:THERMO C18(4.6 mm×250 mm,5μm),检测波长:254 nm,流量:1.0 mL/min,进样量:10μL,流动相:0.02 mol/L乙酸铵与甲醇。梯度条件为:甲醇20%~35%,3%/min;35%~98%,9%/min;98%继续6 min。结果表明:柠檬黄、苋菜红、胭脂红、日落黄在0~50μg/mL范围内呈现良好的线性关系,Y=30 264 440X+3 047.2(R=0.999 8)、Y=29 741 606.67X+607.03(R=0.999 8)、Y=28 790 266.67-6 523.42(R=0.999 8)、Y=25 122 776.67X+1 953.58(R=0.999 8)。色素在24 h内稳定。本方法简单,快速、准确、重现性好,可以用作葡萄酒中色素的含量测定。     

HPLC法测定冬枣环磷酸腺苷含量

采用HPLC法对冬枣中环磷酸腺苷(cAMP)含量进行测定。色谱条件:色谱柱为Hypersil-ODS2(25cm×4.6mm,5μm)柱,流动相为V(甲醇):V(0.05mol/L磷酸二氢钾)=10:90,流速1.0mL/min,紫外检测器UV254nm×0.2AUFS。测定结果表明:标准曲线在1μg/mL～50μg/mL范围内线性良好,回收率为99.14%,相对标准误差为1.32%(n=6)。     

高效液相色谱法测定保健食品多维康胶囊中叶酸的含量

目的建立高效液相色谱法(high performance liquid chromatography,HPLC)测定多维康胶囊中叶酸含量的方法。方法采用C₁₈(150mm×4.6mm,5μm)色谱柱,以磷酸二氢钾-甲醇溶液为流动相,流速0.8 mL/min,检测波长254 nm,柱温30℃,进样体积10μL。结果叶酸的线性关系良好,相关系数为1.000;方法检出限为0.034μg/mL,定量限为0.091μg/mL;方法平均加标回收率为98.80%~104.17%,平均相对标准偏差为0.02%。结论该方法操作简单,灵敏度高,可作为保健食品多维康胶囊中叶酸的测定方法。     

高效液相色谱法测定秘鲁鱿鱼肌肉中的有机酸

研究建立了高效液相色谱(HPLC)同时测定秘鲁鱿鱼肌肉中多种有机酸的方法。有机酸的分离采用Atlantis T3色谱柱(4.6 mm×150 mm,5μm),流动相为0.08 mol/L KH_2PO_4(pH 3.00),流速0.5 mL/min,柱温30℃,检测波长210 nm。丙酮酸、苹果酸、α-酮戊二酸、乳酸、乙酸、柠檬酸、富马酸、丁二酸、丙酸等9种有机酸均能够得到很好的分离,其相关系数均在0.999以上,相对标准偏差为0.03%~0.37%,有机酸的回收率为94.5%~105%。     

高效液相色谱法快速测定红糖中丙烯酰胺

建立了红糖良好水溶性样品的高效液相色谱法检测丙烯酰胺含量的方法。样品未经前处理,直接溶解进样,对色谱柱的选择、紫外检测波长、流动相中有机相比例等实验条件进行优化和考察。结果表明:采用Hypercarb多孔石墨碳液相色谱柱(4.6 mm×100 mm,3μm),在流动相为甲醇-去离子水(15︰85,V/V),流速为1.0 mL/min,紫外检测波长为210 nm的条件下,红糖中丙烯酰胺得到了良好的分离。该方法在0.01~0.16μg/mL范围内线性良好,相关系数为0.9991。丙烯酰胺的检出限为0.003μg/mL,定量限为0.01μg/mL,平均回收率为86.4%~93.4%,日内精密度在1.06%~3.29%,日间精密度在2.34%~4.40%。该方法能有效检测出红糖中的丙烯酰胺,前处理简单,灵敏度高,适用于红糖中丙烯酰胺的日常检测。     

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.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

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.