Global characterization of the photosynthetic glycerolipids from a marine diatom Stephanodiscus sp. by ultra performance liquid chromatography coupled with electrospray ionization-quadrupole-time of flight mass spectrometry

The photosynthetic glycerolipids composition of algae is crucial for structural and physiological aspects. In this work, a comprehensive characterization of the photosynthetic glycerolipids of the diatom Stephanodiscus sp. was carried out by ultra performance liquid chromatography-electrospray ionization-quadrupole-time of flight mass spectrometry (UPLC-ESI-Q-TOF MS). By use of the MS^E data collection mode, the Q-TOF instrument offered a very viable alternative to triple quadrupoles for precursor ion scanning of photosynthetic glycerolipids and had the advantage of high efficiency, selectivity, sensitivity and mass accuracy. Characteristic fragment ions were utilized to identify the structures and acyl compositions of photosynthetic glycerolipids. Comparing the abundance of fragment ions, it was possible to determine the position of the sn-glycerol-bound fatty acyl chains. As a result, four classes of photosynthetic glycerolipid in the extract of Stephanodiscus sp. were unambiguously identified, including 16 monogalactosyldiacylglycerols (MGDGs), 9 digalactosyldiacylglycerols (DGDGs), 23 sulfoquinovosyldiacylglycerols (SQDGs) and 8 phosphatidylglycerols (PGs). As far as our knowledge, this is the first report on global identification of photosynthetic glycerolipids, including lipid classes, fatty acyl composition within lipids and the location of fatty acids in lipids (sn-1 vs. sn-2), in the extract of marine microalgae by UPLC-ESI-Q-TOF MS directly.     

茶叶指纹谱的毛细管胶束电动色谱法研究

 用胶束电动色谱法建立了茶叶的色谱指纹谱并用于分析10种中国名茶。这种色谱指纹谱是由相对保留值(α)和相应的相对峰面积(Sr)组成的。该方法将色谱图转换成数据表,实现了图谱的数据化;并且以相对保留值表示各色谱峰的峰位,大大减少了各种操作条件对色谱相对保留值的影响,降低了色谱峰峰位变化的波动性,提高了样品间的可比性。这种色谱指纹谱在没有标准品的情况下也可得出可靠的、有意义的结果。优化后的色谱条件是:电泳电解质为硼砂0.02 mol/L 、十二烷基硫酸钠(SDS)浓度为0.025 mol/L 的溶液(pH     

银杏叶提取物的多维指纹图谱研究

利用高效液相色谱/二极管阵列检测/质谱/质谱法,建立了银杏叶提取物的多维指纹图谱,同时建立了总离子流指纹图谱,使同时检测银杏叶中两类有效成分黄酮和内酯类化合物成为可能。采用Zorbax SB-C18色谱柱(250 mm×4.6 mm i.d., 5 μm),流动相为水(含0.5 %甲酸)和乙腈,二元梯度洗脱,流速为1.0 mL/min,350 nm下检测。采用电喷雾离子源,负离子检测模式下采集质谱数据。利用指纹图谱相似度计算软件,以芦丁为内参比峰,考察了不同厂家银杏叶提取物与标准银杏叶提取物EGb 761     

栀子药材的指纹图谱整体性分析

建立了药材栀子水提部分的高效液相色谱指纹图谱,脂溶性成分和挥发油的气相色谱．质谱联用指纹图谱,并分别计算了此3部分指纹图谱的相似系数和总体相似系数,同产地结果RSD≤5％。通过比较不同产地栀子相似系数的关系,以及对9个主要药效成分定量结果的分析,对不同产地栀子的指纹图谱做了整体性评价,结果表明,只有全面测定成分及整体性评价后,药材的质量才能得到有效评价。     

改进的广义回归神经网络用于基于气相色谱法的原油密度定量分析

在油气勘探开发领域,快速识别储集层原油性质对于工程技术人员有非常重要的指导意义.地球化学录井技术是用于判断储集层原油性质的常规手段,能为储集层综合评价提供专业认识.该文研究了地化录井中的岩石热解分析和气相色谱分析的原理,提出了一种利用色谱谱图对原油密度进行定量分析的新方法,再结合原油性质密度划分标准,可快速判断储集层原...     

色谱指纹图谱在香精香料质量控制中的应用

烟用香精香料化学成分复杂,现无合适的化学质量控制方法,通过实例,对10个批次正常生产的香料标样进行同时蒸馏萃取,取其萃取液进行气相色谱氢焰检测.进行同组分色谱峰的匹配,根据相对峰面积求出标准指纹图谱,然后10批标样各自与标准指纹图谱进行相似度计算,据此设立待测样品的合格性允差范围.待测样品与标准指纹图谱进行谱峰匹配,计算与标准指纹图谱的相似度,依据合格性允差范围,判定其质量状况.     

Adsorption and desorption characteristics of ginsenosides from Panax ginseng C. A. Meyer on middle‐pressure chromatogram isolated gels

Four types of middle‐pressure chromatogram isolated gels are evaluated for adsorption or desorption characteristics of ginsenosides from Panax ginseng. Among them, SP207SS and SP2MGS were selected for dynamic investigations based on their static adsorption or desorption capacity of total ginsenoside. Their adsorption kinetics was better explained by pseudosecond‐order model and isotherms were preferably fitted to Langmuir model. Dynamic breakthrough experiments indicated an optimum sample loading speed of 4 bed volume/h for either SP207SS or SP2MGS. Desorption speed was determined to be 2 bed volume/h according to desorption amount of total ginsenoside in their effluents. Eight ginsenosides were identified and quantified by high performance liquid chromatography‐triple quadropole‐mass spectrometry in total ginsenoside extract and different fractions during stepwise dynamic elution. For SP207SS, 27.62% of loaded ginsenosides was detected in 40% ethanol fraction, while 59.12% of them were found in 60% ethanol fraction. As on SP2MGS, the number went to 53.71 and 44.43%, respectively. Recovery rate of ginsenosides were calculated to 78.65% for SP207SS and 89.53% for SP2MGS, respectively. Intriguingly, content of Rg1 and Re in 40% ethanol fraction from SP207SS became 20.1 and 18.6 times higher than that in total ginsenoside extract by one‐step elution, which could be leveraged for the facile enrichment of these two ginsenosides from natural sources.     

闪蒸-气相色谱指纹图谱及系统聚类分析用于烟用香精香料的测定

采用闪蒸-气相色谱法(FE-GC)对不同黏度的烟用香精香料样品进行测定,考察了影响测定的主要因素。结果表明,0.40 mg样品在350 ℃下进行FE-GC分析,可以得到重现性良好的色谱图。与超声辅助液-液萃取-气相色谱法(ULLE-GC)分析结果的比较表明,FE-GC适用于不同黏度样品的分析。采用该法检测了中等黏度的烟用香精香料1184号8个批次样品,并建立其指纹图谱。利用系统聚类分析法可以明显区分1184号样品及掺兑10%～30%其他种类烟用香精香料的样品。FE-GC法简便、快速、灵敏,适用于不同黏度的烟用香精香料样品的检测和质量控制分析。     

The determination of the linear alkylbenzene sulfonate isomers in water samples by gas-chromatography/mass spectrometry

A number of 20 compounds of linear alkylbenzene sulfonates (LASs) family were identified by electron impact mass spectrometry (EI-MS) in water samples collected from wastewater treatment plants (WWTP). This paper presents the mass spectra of 20 compounds, the proposed mechanism of formation of the diagnostic ions obtained by EI-MS and the distribution of individual isomers in water samples collected from compartments of WWTP. The individual isomers from four homolog series C(10)-, C(11)-, C(12)- and C(13)-LAS were analyzed as methyl derivatives.     

槲寄生药材的高效液相色谱指纹图谱研究

采用Diamonsil C<,18>(2)色谱柱,乙腈-0.1%磷酸梯度洗脱,测定了15批不同产地的槲寄生样品,建立其指纹图谱共有模式;采用"中药色谱指纹图谱相似度评价系统"软件进行数据处理,聚类分析,建立槲寄生药材高效液相色谱指纹图谱.结果表明:以高圣草素-7-O-β-D-芹菜糖基(1→2)-β-D-葡萄糖苷为参照物...