HPLC法测定大豆磷脂及其保健品中PC、PI、PE

建立了高效液相色谱紫外检测器测定大豆保健品中磷脂酰胆碱、磷脂酰乙醇胺、磷脂酰肌醇的测定方法。采用NH2色谱柱(3.0 mm×150 mm×5μm),流动相为乙醇∶乙腈∶水=50∶40∶10(体积比),流速0.4 m L/min下,紫外检测器波长为206 nm处进行测定。样品经正己烷∶异丙醇=1∶1(体积比)混合液溶解并使用流动相稀释后直接进样分析。在线性范围内相关性良好,相关系数R2≥0.999,各添加水平回收率为91.12%~105.61%,RSD为4.85%,日内和日间精密度均小于4%,磷脂酰胆碱、磷脂酰乙醇胺、磷脂酰肌醇定量限分别为1.5 mg/L、1.2 mg/L和0.9 mg/L。本方操作简单、准确、成本低,适合于分析大豆磷脂及其保健品中三种主要磷脂的含量。     

正相色谱法测定大豆磷脂中的磷脂酰胆碱

目的建立正相色谱法测定大豆磷脂中磷脂酰胆碱含量,用于大豆磷脂类保健食品生产过程中该物质含量的测定和质量控制。方法采用硅胶柱(4.6 mm×250 mm,5.0μm)进行分离;色谱条件为流动相:异丙醇:正己烷:蒸馏水=70:16:14(V:V:V),等度洗脱,流速:1.0 m L/min;柱温:40℃;进样量:10μL;检测波长:205nm;并进行方法学验证,考察方法检测限、精密度、回收率等指标。结果磷脂酰胆碱峰面积与其浓度呈良好的线性关系,线性范围为0.1~0.8 mg/m L(r=0.9999),检出浓度0.04μg/m L,检出限为20μg/g,定量限为66.666μg/g,精密度(RSD)为0.6%,平均回收率99.37%(n=9)。结论本文建立的方法灵敏度高,重复性好,且具有很好的专属性,能够应用于大豆磷脂类保健食品中磷脂酰胆碱含量的检测。     

山杏内种皮磷脂类化合物提取与测定

以山杏内种皮为原料,采用超声波辅助萃取法提取磷脂类化合物,并利用高效液相色谱法分离测定含量。以总磷脂得率为评价指标,通过单因素试验和正交试验优化超声波辅助萃取条件。结果表明,以正己烷-乙醇(1∶1,体积比)为提取溶剂,料液比为1∶15(g/mL),超声功率为450 W,超声时间为50 min最优,在此条件下,山杏内种皮总磷脂含量为0.091 2%。高效液相色谱-紫外检测器法测定磷脂含量,采用ZORBAX Rx-SIL型硅胶柱(4.6 mm×250 mm,5μm),流动相为乙腈-甲醇(15∶85,体积比),流速1.0 mL/min,柱温35℃,进样量20μL,测得山杏内种皮中磷脂酰乙醇胺(PE)含量为0.393 4 mg/g。     

大豆磷脂中卵磷脂检测方法的研究

采用高效液相色谱法对大豆磷脂中的磷脂酰胆碱进行检测,详细介绍了样品的预处理、检测设备和检测条件。试验确定了最佳检测条件:流动相为正己烷-异丙醇-醋酸(1%,V/V)(8∶8∶1,V/V/V);色谱柱Lichroisorb Si-60(4.6mm×250mm×5μm);检测波长203nm;流速1mL/min;柱温30℃。     

气相色谱法测定氨磷汀原料药中N,N-二甲基甲酰胺残留量

建立气相色谱法测定氨磷汀中N,N-二甲基甲酰胺的残留量。采用RTX-624色谱柱(30m×0.53mm×3.0μm),以氮气为载气,FID检测,顶空进样,测定残留溶剂的含量。N,N-二甲基甲酰胺在34.9~251.1μg/mL浓度范围内线性关系良好,相关系数r=0.9992,回收率为102.2%,低检测限为13.53μg/mL。     

溶剂体系与无溶剂体系下大豆油脱胶工艺比较研究

在溶剂体系(正己烷)与无溶剂体系下对大豆油脱胶工艺进行了比较研究.结果表明:溶剂体系下,对大豆油脱胶效果影响最大的因素是油与溶剂比,其次是加水量,而反应温度、反应时间影响较小.将含溶剂大豆油(大豆油与正己烷质量比4.0∶1)预热至60c℃,添加6％(占油质量)的水,10 000 r/min下均质1 min,搅拌反应30 min后获得的脱胶油磷脂含量可降至136.0 mg/kg(磷含量5.2 mg/kg),脱胶率达99.5％,脱胶油酸值降低,甘一酯基本消失.无溶剂体系下添加酸类脱胶剂时脱胶油磷脂含量可降至58.6 mg/kg.与无溶剂体系相比,溶剂体系下获得的脱胶副产物磷脂色泽更浅,品质更好.     

气相色谱法测定替比培南酯中的残留溶剂

目的建立替比培南酯中残留溶剂含量测定方法。方法采用程序升温顶空气相色谱法,使用毛细管色谱柱(DB-624,30 m×0.53 mm,3.0μm),测定乙腈、乙醇、乙酸乙酯、正丁醇、异丙醇、甲基叔丁基醚和N, N-二甲基甲酰胺的含量。结果 7种残留溶剂的检测限在70.173～2.084μg/ml之间,精密度试验结果RSD在1.25%～4.34%之间,回收率测定结果在96.36%～100.98%。结论本方法简便、快速、灵敏度好、可有效测定替比培南酯中残留溶剂含量。     

加速溶剂萃取结合亲水液相色谱柱分离测定坚果中的8种生育酚异构体

目的建立加速溶剂萃取(ASE)结合亲水液相色谱(HILIC)柱分离测定坚果中8种生育酚异构体的方法。方法 2 g坚果样品经ASE提取富集后,用BEH Amide色谱柱(150 mm×3.0 mm,1.7μm)分离,以90%正己烷,10%叔丁基甲基醚-四氢呋喃-甲醇(20∶1∶0.1,V/V)作为流动相等度洗脱,荧光检测器激发波长294 nm,发射波长328 nm检测,外标法定量。结果 4种生育酚在0.5~80.0μg/ml、4种生育三烯酚在0.5~30.0μg/ml之间具有良好的线性(r~20.998),方法检出限在0.032~0.070 mg/kg之间,方法定量限范围0.096~0.210 mg/kg,三个水平加标回收率在87.5%~114.2%之间,6次重复测定相对标准偏差(RSD)均≤12%。结论本方法具有良好的灵敏度、回收率和重复性,适用于坚果中8种生育酚异构体的含量分布的测定。     

高效液相色谱法测定大豆磷脂类保健食品中的磷脂酰胆碱、磷脂酰乙醇胺、磷脂酰肌醇

目的建立高效液相色谱检测法测定大豆磷脂类保健食品中磷脂酰胆碱(phosphatidylcholines,PC)、磷脂酰乙醇胺(phosphatidylethanolamine, PE)、磷脂酰肌醇(phosphatidylinositol, PI)含量的方法。方法大豆磷脂类保健食品试样经正己烷:异丙醇(1:1, V:V)提取,经氨基柱(250 mm×4.6 mm, 5μm)分离,以流动相为无水乙醇-乙腈-水(50:40:10, V:V:V)为流动相等度洗脱,流速为0.4 mL/min,检测波长为205 nm,外标法定量。结果磷脂酰胆碱、磷脂酰乙醇胺、磷脂酰肌醇在一定浓度范围内线性关系良好,相关系数大于0.999;检出限分别为1.3、5.0、1.0 mg/g,加标回收率分别为95.5%、99.5%、94.9%,精密度均为0.3%。结论本方法准确度高、重复性好,适用于保健食品中磷酯类物质含量的测定。     

顶空气相色谱法测定叶黄素中有机溶剂残留量

目的建立叶黄素中正己烷、乙醇和乙酸乙酯有机溶剂残留量的顶空气相色谱分析方法,并用该方法测定样品中的有机溶剂残留量。方法采用顶空气相色谱法,色谱柱为DB-624毛细管色谱柱(30 m×0.53 mm×3μm),载气为氦气,检测器为氢火焰离子化检测器,以程序升温方式使正己烷、乙醇和乙酸乙酯达到完全分离,外标法定量。结果正己烷、乙醇和乙酸乙酯的线性范围分别为4.95¹98 mg/L(r=0.99998)、8.295198 mg/L(r=0.99998)、8.295³31.8 mg/L(r=0.99994)和8.325331.8 mg/L(r=0.99994)和8.325³33 mg/L(r=0.99999);平均回收率范围为97.79%333 mg/L(r=0.99999);平均回收率范围为97.79%¹03.21%,精密度(以相对标准偏差计,n=3)为1.47%103.21%,精密度(以相对标准偏差计,n=3)为1.47%³.46%;检测限分别为0.09、0.83和0.33 mg/L。利用本方法对实际样品叶黄素中有机溶剂残留量进行了测定,结果表明,该样品中含有正己烷和乙醇,其含量分别为12 mg/kg和45 mg/kg。结论本方法快速、灵敏、准确,适用于叶黄素中残留溶剂的检测。     

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.     

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.     

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.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Detection of adulteration of locust bean gum with guar gum by capillary electrophoresis and polarized light microscopy

Capillary electrophoresis (CE) and polarized light microscopy (PLM) were utilized in the detection of the adulteration of locust bean gum with guar gum. For CE analyses, standards of locust bean and guar gums were extracted with 30% CH₃CN, removing the residual proteins from the gum matrix. A 8.75 mM NaH₂PO₄-20.6 mM Na₂B₄O₇ buffer, pH 9, was used to separate these proteins and to identify marker proteins that were present in the guar gum. These markers did not co-migrate with components in the extracts of mechanically processed locust bean gum, and are used as indicators of adulteration. Using PLM with toluidine blue and iodine staining techniques, unadulterated locust bean gum samples were distinguished from mixed samples through the differential staining of components in locust bean versus guar and tara gums. These experiments in the use of CE and PLM provide orthogonal and complementary methods for the verification of 'true' positives and the elimination of 'false' positives.