毛细管电泳-电化学发光法测定荷叶中荷叶碱与莲子心中莲心碱含量

建立毛细管电泳-电化学发光法同时测定荷叶中荷叶碱与莲子心中莲心碱含量的方法。对三联吡啶钉(Ru(bpy)_3~(2+))溶液浓度、检测电位、磷酸盐缓冲液浓度和pH值、进样时间和分离电压等实验条件进行考察和优化。结果表明,在检测电位为1.20 V,运行缓冲液为10 mmol/L磷酸盐缓冲液(pH 5.74),5 mmol/L Ru(bpy)_3~(2+)溶液,检测池内磷酸盐缓冲液浓度为60 mmol/L(pH 8.30),进样电压为8 kV,进样时间为10 s,分离电压为13 kV,荷叶碱检出限为7.7×10~(-7)mol/L(R_(SN)-3),莲心碱检出限为7.8×10~(-7)mol/L(R_(SN)-3)。对浓度为6.8×10~(-5)mol/L荷叶碱和3.1×10~(-5)mol/L莲心碱的标准品溶液进行5次平行测定表明:荷叶碱峰面积的相对标准偏差(relative standard deviation,RSD)为3.76%,迁移时间RSD为0.83%;莲心碱峰面积RSD为4.28%,迁移时间RSD为1.37%。该方法可用于测定荷叶中的荷叶碱与莲子心中莲心碱含量。     

高效液相色谱法测定不同产地湘莲中荷叶碱、 莲心碱、芦丁的含量

目的建立高效液相色谱法同时测定湘莲中荷叶碱、莲心碱、芦丁的方法。方法在酸性条件下超声提取3种待测组分。色谱条件如下:C_(18)(250 mm×4.6 mm,5μm)色谱柱;流动相:甲醇-0.1 mol/L乙酸铵(用乙二胺调节pH值至7.5~8.0)(55:45,V:V);流速:1.0 m L/min;检测波长:275 nm;柱温30℃;进样量10μL。结果荷叶碱、莲心碱、芦丁分别在7.636~152.7μg/mL(r~2=0.9999,n=5)、7.543~150.9μg/mL(r~2=0.9995,n=5)、7.543~150.9μg/mL(r~2=0.9998,n=5)范围内线性关系良好,加标回收率为96.9%~100.5%之间,相对标准偏差(relative standard deviation,RSD)为1.1%~1.4%。结论该法同时测定湘莲中荷叶碱、莲心碱、芦丁,简单快速,定量准确,可以为评价不同产地湘莲功效成分提供参考。     

荷叶中荷叶碱的高效液相色谱检测方法及其提取工艺研究

通过正交试验探讨用乙醇回流提取荷叶中荷叶碱的最佳工艺,并建立荷叶碱含量测定的高效液相色谱测定方法。结果表明,用75%的乙醇在90℃温度下按固液比为1∶20(m∶V)回流提取3.5h,荷叶碱回收率高于95%;高效液色谱检测其含量在43.16～258.96μg/mL有很好的线性关系,相关系数达0.999 3,最低检出量为0.103 4μg/mL。说明用该方法提取荷叶碱可行,测定结果稳定、精确。     

山楂荷叶复合固体饮料的制备工艺优化及功能性成分含量测定

目的:建立一种以山楂荷叶为主要原料的固体饮料的制备工艺,同时拟定总黄酮和荷叶碱为主要质量控制指标,建立其含量测定方法。方法:分别以总黄酮含量和水溶性生物碱的雷氏盐沉淀量及干膏得率为指标,通过正交试验确定荷叶和莱菔子有效成分的最佳提取工艺;分别采用紫光分光光度法和反相高效液相色谱法测定总黄酮及荷叶碱的含量。结果:荷叶的最佳提取工艺为60倍量80%乙醇于80 ℃回流提取2次,每次2.5 h;莱菔子的最佳提取工艺为10倍量水提取3次,每次1.5 h。含量测定的结果为:芦丁在0.0192~0.1152 mg/mL范围内线性关系良好(r=0.9996),平均加样回收率为100.53%,RSD值为1.45%(n=6);荷叶碱在1.5~24.0 μg/mL范围内线性关系良好(r=0.9999),平均加样回收率为100.16%,RSD值为1.17%(n=6)。结论:设计的制备工艺合理、可行,含量测定方法简便、准确、重复性好,可为山楂荷叶复合固体饮料的生产和质量控制提供科学依据。     

高效液相-阳离子交换色谱法测定藏药安神丸中槟榔碱的含量

目的建立高效液相-阳离子交换色谱法测定藏药安神丸中槟榔碱含量的方法。方法样品用乙醚溶液和碳酸盐缓冲液提取后,用Sepax Polysulfonix-SCX(250 mm×4.6 mm,5μm)强阳离子交换树脂色谱柱分离,以乙腈-0.2%磷酸溶液(pH 3.8,10:90,V:V)作为流动相进行洗脱,0.5 mL/min流速,用紫外检测器于215 nm波长处进行测定。结果氢溴酸槟榔碱在7.028~210.840μg/mL范围内线性关系良好(r~2=0.9998),回归方程为Y=44.5058X-56.3314,加标回收率为95.67%~97.41%,相对标准偏差为1.07%~1.80%(n=3)。结论此方法具有良好的精密度、稳定性及回收率,可用于安神丸中槟榔碱成分的测定。     

超声辅助提取-高效液相色谱法测定荷叶中的生物碱

采用超声提取法提取荷叶中的O-去甲荷叶碱、N-去甲荷叶碱、荷叶碱和莲碱4种主要的生物碱,建立HPLC分析方法进行评价,为荷叶及相关产品的质量控制提供参考。选用Welch Materials C18色谱柱(250 mm×4.6 mm,5μm),以乙腈-水(含0.1%三乙胺)为流动相进行梯度洗脱,实现了O-去甲荷叶碱、N-去甲荷叶碱、荷叶碱和莲碱4种生物碱的同时基线分离。在0.1～50μg/mL范围内,O-去甲荷叶碱(R=0.999 8)、N-去甲荷叶碱(R=0.999 9)、荷叶碱(R=0.999 8)和莲碱(R=0.999 8)具有良好的线性关系,检出限分别为1.87、2.22、2.34和1.88 ng/mL(S/N=3∶1)。     

高效液相色谱法测定南瓜粉中胡芦巴碱的含量

目的:建立高效液相色谱法测定南瓜粉中胡芦巴碱的方法.方法:甲醇超声波提取样品中的胡芦巴碱,色谱柱为Zorbax-NH2(4.6×150mm,5μm),流动相为乙腈-水(80∶20,V∶V),流速为1ml/min,检测波长为265nm.结果:胡芦巴碱浓度在5.01～101.4μg/ml内呈现良好的线性关系,相关系数r=0.9999(n=5);精密度实验RSD=0.31%(n=5);平均回收率为85.28%,RSD=4.4%(n=6);测定三个品系的30个样品中南瓜粉中胡芦巴碱的含量为0.1219～0.4836mg/g.结论:首次建立了高效液相色谱法测定南瓜中胡芦巴碱含量的方法,为南瓜功能性成分开发和遗传育种提供了理论依据.     

灯笼果中噻菌灵的RP-HPLC-PDA 残留分析

目的：建立反相高效液相色谱-二极管阵列检测器测定灯笼果中杀菌剂噻菌灵残留的分析法。方法：色谱柱为Shim-pack VP-ODS(150mm×4.6mm),检测波长为299nm,流动相为pH6.8的乙腈-0.02mol/L磷酸缓冲溶液(70:30,V/V),流速为0.6mL/min,进样量20μL。结果：噻菌灵在0.10～90.0μg/mL范围内与峰面积成良好线性关系(r＝0.9995),检测限为0.05μg/mL,噻菌灵的回收率为87.9%～102.6%,相对标准偏差为0.98%～2.79%。结论：该方法操作简便快速,可作为灯笼果中噻菌灵含量监测的控制方法。     

荷叶生物碱的提取工艺优化及其清除羟基自由基能力的测定

研究了荷叶中生物碱的提取优化工艺及其抗氧化效果.采用正交实验设计,考察提取温度、提取时间、料液比和酸水pH对生物碱提取效果的影响.结果表明,最佳提取工艺为酸水pH2.5,提取温度80℃、提取时间2h和料液比1∶40;荷叶碱在5.20～26.00μg/mL范围内具有良好的线性关系,r=0.994,荷叶中荷叶碱的含量占荷叶生物碱水提物含量的1.752%;浓度为7mg/mL荷叶生物碱水提物溶液对水杨酸体系中羟基自由基(·OH)的清除率为55.2%.     

高效液相色谱法测定豆制品中的甲醛

目的建立高效液相色谱法测定豆制品中甲醛含量的分析方法。方法样品粉碎后,采用乙腈-2,4-二硝基苯肼和磷酸二氢钠溶液的混合体系为衍生溶液提取样品中的甲醛,生成的产物经色谱柱WelchXB-C_(18)(4.6mm×250mm,5μm)洗脱,流动相为乙腈-水(70:30,V:V),柱温为35℃,流速为0.8mL/min;检测波长为355 nm,高效液相色谱法检测。结果甲醛质量浓度在0～3.0μg/mL范围内呈良好线性,相关系数r~2为0.9999,在2、10和40μg3个加标水平的回收率为87.22%～93.92%,相对标准偏差为0.75%～3.87%,检出限为0.05mg/kg。结论本方法灵敏度高,操作简便,准确可靠,适合于测定豆制品中甲醛的含量。     

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.     

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.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press