基于GC-TOF/MS技术的转Bt基因大米代谢组学研究

基于GC-TOF/MS技术对来源于两个不同产地的转Bt基因及其亲本大米进行了代谢组学研究。从大米样本中共检出774个色谱峰,鉴定出278种代谢产物,包括糖、氨基酸、脂肪酸及有机酸等代谢产物。对转Bt基因及其亲本大米进行主成分分析,结果表明,转Bt基因与亲本大米的代谢组之间无明显差异性,进一步对数据进行偏最小二乘判别分析和方差分析,仅甘油和鼠李糖两种代谢产物浓度在转Bt基因大米及其亲本大米间存在一定差异(分别升高1.55和3.32倍);考察了不同产地对大米代谢组的影响,结果表明武汉和海南两个产地的大米代谢组之间存在明显差异,有15种代谢产物在不同产地的亲本大米之间以及不同产地的转基因大米之间均发生显著变化。应用GC-TOF/MS技术对来源于不同产地的转Bt基因大米及其亲本大米的代谢组进行比较研究,结果表明引入外源Bt基因对实验中的水稻机体内代谢未产生明显影响,产地差异造成的大米间代谢组差异比引入外源Bt基因造成的大米间代谢组差异更为显著。     

气相色谱结合化学计量学区分大米贮藏时间与产地

香气是衡量大米质量的一个主要因素,对大米的食用品质有重要影响。该文以顶空固相微萃取(SPME)技术为基础,采用气相色谱法分别分析了不同贮藏时间和不同产地大米样本的挥发性成分,通过主成分分析法(PCA)和偏最小二乘判别分析法(PLS-DA)对大米样本进行分类和判别分析。PCA及PLS投影图显示不同储藏时间的大米明显聚为4类,通过留一交叉验证法(LOO)计算PLS预报的准确率为96%,相对标准误差为8.2%。同时,PCA投影图中可将4个不同产地的大米样本进行区分,分类效果显著;所建PLSDA模型可靠,不同产地大米样本均能被准确识别,正确率为100%。以顶空固相微萃取/气相色谱检测大米中挥发性成分,利用主成分分析法和偏最小二乘判别分析法鉴别大米新鲜程度和产地具有可行性。     

基于选择离子集成谱的中药质量评价新方法

采用液相色谱-质谱(LC-MS)联用技术建立了不同产地的双丹方(丹参和丹皮)煎剂的指纹图谱, 并提出一种将二维的LC-MS数据转化为一维的选择离子集成谱(ISIC)的方法. 通过主成分分析考察了ISIC与总离子流色谱图(TIC)和保留时间校正后的TIC对不同产地药材的区分能力. 结果表明, ISIC能全面反映不同产地的丹参和丹皮成分间的差异; 而TIC由于色谱峰重叠严重, 对不同产地的药材无区分能力, 保留时间校正后的TIC仅能反映不同产地丹参成分间的差异. 该方法运算速度快, 适于大批量样本分析, 生成的ISIC信息量大, 且不需校正保留时间, 可直接用于后续的统计分析.     

基于多元统计学的青稞HPLC指纹图谱研究

为了筛选品质良好的青稞,选择不同产地的10批青稞样品,建立了青稞的高效液相指纹图谱,并进行了聚类分析和主成分分析,测定了儿茶素、表儿茶素和芦丁3种指标成分的含量.首先采用高效液相色谱法测得了10批青稞的色谱图,建立其共有模式,确定了11个共有峰,蓝青稞指标成分含量均高于白青稞.对共有峰数据进行聚类分析和主成分分析,10...     

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。     

丹参脂溶性成分结构优化研究进展

丹参作为一种传统中药在临床上广泛应用于心脑血管疾病的治疗,对其有效成分及衍生物的研究一直是国内外的研究热点.丹参的有效成分主要分为脂溶性成分和水溶性成分,其脂溶性成分具有多种药理活性,但因其水溶性不足、生物利用度低的缺点限制了临床应用.为了能够推进丹参脂溶性成分的临床应用,研究人员以丹参脂溶性成分为先导化合物进行结构优化,以期能够提高其类药性.综述了近年来丹参主要脂溶性成分的结构优化及相关药理活性的研究进展,总结了主要脂溶性成分的成药性结构优化策略以及该类衍生物的合成方法,阐述了不同位置结构优化对药理活性的影响,旨在为丹参脂溶性成分创新药物的研发提供新的研究思路.     

不同产地黄芪的红外光谱鉴别研究

采用红外光谱、二阶导数红外光谱和二维相关红外光谱,对四种不同产地的黄芪原药材进行了鉴别研究。结果表明:不同产地黄芪的红外光谱和二阶导数红外谱具有一定的相似度,与淀粉的红外谱图比对,4个不同产地的黄芪均含有淀粉,其中陕西绥德产黄芪的淀粉含量比其它3个产地黄芪的都要高。山西浑源和山西天镇产黄芪谱图的1 510、1 425cm-1木质素特征峰比内蒙古固阳和陕西绥德产黄芪的更为明显,说明前二者产黄芪中木质素含量高于后二者产黄芪。在二维相关红外谱图上,根据4个产地黄芪的相对峰强度的差异,可进行产地的鉴别。研究结果表明对于不同产地黄芪的鉴别,红外三级鉴定法是一种快速有效的新方法。     

脐橙果皮的室温和热辅助表面解吸常压化学电离质谱的比较

以脐橙果皮为研究对象,比较了室温和热辅助表面解吸常压化学电离源(DAPCI)的解吸电离特性,结合串联质谱技术,对果皮中香气、糖、黄酮类等主要成分进行了鉴定,并通过主成分分析(PCA)方法对热辅助DAPCI-MS所获外果皮指纹谱图信息进行分析,进而区分了3个不同产地脐橙。 结果表明,室温DAPCI-MS对脐橙果皮中的香气成分具有较强的解吸电离能力,而热辅助DAPCI-MS则更适合于分析果皮中的黄酮类和糖类及其衍生物。 DAPCI-MS具有灵敏度高、分析速度快等特点,有望成为农产品品质快速检测与产地识别研究的新方法。     

红外光谱法直接鉴别苦丁茶的研究

本文利用傅立叶变换红外光谱(FTIR)法快速、直接地测定了11种苦丁茶,并对所获得的指纹图谱进行特征峰指认和对比分析。结果表明:各种苦丁茶化学成分相同,而由于各成分间的相对含量的不同,使每种样品都有自己独特的红外谱图,不同产地、不同级别苦丁茶的红外吸收频率、吸收峰的相对强度都存在比较大的差异。同时还运用傅立叶变换红外光谱技术对不同产地、不同级别苦丁茶的混合化学体系进行了全组分快速分析,为苦丁茶的鉴别及质量控制提供了可靠的依据。     

微波辅助-顶空固相微萃取-气相色谱-质谱法测定不同产地烟草中挥发性成分

提出了微波辅助-顶空固相微萃取(MAE-HS-SPME)-气相色谱-质谱法测定不同产地烟草中挥发性成分。通过质谱标准谱图检索与色谱保留指数相结合的二维定性方法分析,以峰面积归一化法计算各组分的相对含量。结果表明:从我国湖南、贵州和云南省以及从津巴布韦等产地的烟草中分别定性检出24,28,27,24种挥发性成分,包括酯类、酮类、醇类、酸类、杂环、烷烃类等6大类化合物,以酯类和烷烃类为主。不同产地烟草所含化学成分的种类基本相同,但是其相对含量差异较大。MAE-HS-SPME是一种简便、快速、高效、绿色环保的前处理技术。     

Combination of quantitative analysis and chemometric analysis for the quality evaluation of three different frankincenses by ultra high performance liquid chromatography and quadrupole time of flight mass spectrometry

Frankincense has gained increasing attention in the pharmaceutical industry because of its pharmacologically active components such as boswellic acids. However, the identity and overall quality evaluation of three different frankincense species in different Pharmacopeias and the literature have less been reported. In this paper, quantitative analysis and chemometric evaluation were established and applied for the quality control of frankincense. Meanwhile, quantitative and chemometric analysis could be conducted under the same analytical conditions. In total 55 samples from four habitats (three species) of frankincense were collected and six boswellic acids were chosen for quantitative analysis. Chemometric analyses such as similarity analysis, hierarchical cluster analysis, and principal component analysis were used to identify frankincense of three species to reveal the correlation between its components and species. In addition, 12 chromatographic peaks have been tentatively identified explored by reference substances and quadrupole time‐of‐flight mass spectrometry. The results indicated that the total boswellic acid profiles of three species of frankincense are similar and their fingerprints can be used to differentiate between them.     

Improved liquid chromatography fingerprint of fat-soluble Radix isatidis extract using multi-wavelength combination technique

We first investigated liquid chromatography (LC) fingerprint method using multi-wavelength combination technique, and successfully used this method for the analysis of a fat-soluble extract from Radix isatidis. LC fingerprints of fat-soluble R. isatidis extracts from 11 origins were established using the Origin software and Similarity Evaluation System for Chromatographic Fingerprints of traditional Chinese medicine (TCM). The typical LC fingerprints of fat-soluble extracts from R. isatidis were first established, and the reference chromatogram was also generated with 24 common peaks showing large peak areas and good separation from adjacent peaks. Seven common characteristic peaks were identified for the first time: anthranilic acid, syringic acid, benzoic acid, salicylic acid, tryptanthrin, indigo and indirubin. The total peak areas of 24 common peaks were more than 80% of the total peak areas. Hierarchical clustering analysis (HCA) of 11 R. isatidis samples was performed, and the results show that the differences between 11 origin R. isatidis were large. Principal component analysis (PCA) on 24 common peaks was obtained to find the possible chemical markers for the discrimination of different samples. The loading plot indicated that peaks 8, 11, 13 and 14 may have more influence on the discrimination of the samples. All these were useful for evaluating and controlling the quality of R. isatidis. Our work provides a general model of chromatogram combination at multi-wavelength detection to study the complex or the undeveloped materials, which can be used to scientifically ensure the quality of such samples and deeply do qualitative, quantitative and multicomponent pharmacodynamic research combined with modern advanced chromatographic technique.     

气相色谱-质谱联用分析茶树油的成分

采用常规水蒸气蒸馏法从茶树枝叶中提取茶树油，经气相色谱-质谱联用分析，分离出47种成分，检索NI蚋8质谱数据库，与标准谱图对照鉴定了其中32种成分。应用Hewlett—Packard软件，按峰面积归一化法定量，所鉴定成分的馏出峰面积占总馏出峰面积的96．08％。     

涂石蜡大米傅立叶变换红外吸收光谱识别分析

针对11种未涂石蜡大米和18个涂不同量石蜡的大米样品,以石油醚提取的油脂为试样,采用傅立叶变换红外光谱仪,扫描样品的傅立叶变换红外吸收光谱,并对光谱进行预处理,提取红外特征信息,将2855与1746、1462与1163 cm-1处特征峰的面积比值为坐标,采用Origín 6.0软件作识别分类图.结果表明:特征峰的面积比值与所涂石蜡量成线性变化,大米油脂的特征峰面积比值在一定的区域分布,涂以0.05%以上石蜡的大米,其油脂特征峰面积比值与未涂石蜡米油脂的值有一定区别.     

人工蚕蛹虫草和冬虫夏草水溶性成分的相对归属分析

为对相近中药的化学指纹图谱进行比较研究,充分利用联用色谱所得的光谱、色谱信息与光谱相关色谱方法,分析了蚕蛹虫草和冬虫夏草的水溶性成分的异同,实现了蚕蛹虫草和冬虫夏草水溶性成分化学指纹图谱中相应化学组分的归属分析。其中,蚕蛹虫草和冬虫夏草有5个共有组分,分别有4个和6个相异组分。实验表明：该方法可对复杂中药成分及其指纹图谱进行快速比较分析。     

气相色谱/离子阱质谱中组分图谱提取的主成分分析方法

由于离子阱质谱中容易发生分子-离子反应, 致使质谱图发生改变, 影响与主要由四极质谱建立的参照图谱的匹配效果. 本文采用主成分分析方法对气相色谱/离子阱质谱中组成色谱峰的所有全扫描质谱进行提取, 提取后的质谱图能够有效克服分子-离子反应和基线干扰的影响, 应用不同的匹配算法均能很好地和参照图谱匹配, 和传统方法相比匹配度显著提高, 对目标化合物定性准确.     

Chromatographic–Mass Spectrometric Analysis of Fischer–Tropsch Synthesis Products

The products of Fischer–Tropsch synthesis were comprehensively analyzed by chromatography–mass spectrometry using the AMDIS software and the NIST/EPA/NIH mass spectral database. Structures of more than 90% of the major components were established, and their retention indices and quantitative concentrations in the mixture were determined.     

Differentiation of human kidney stones induced by melamine and uric acid using surface desorption atmospheric pressure chemical ionization mass spectrometry

Clinically obtained human kidney stones of different pathogenesis were dissolved in acetic acid/methanol solutions and then rapidly analyzed by surface desorption atmospheric pressure chemical ionization mass spectrometry (SDAPCI-MS) without any desalination treatment. The mass spectral fingerprints of six groups of kidney stone samples were rapidly recorded in the mass range of m/z 50-400. A set of ten melamine-induced kidney stone samples and nine uric acid derived kidney stone samples were successfully differentiated from other groups by principal component analysis of SDAPCI-MS fingerprints upon positive-ion detection mode. In contrast, the mass spectra recorded using negative-ion detection mode did not give enough information to differentiate those stone samples. The results showed that in addition to the melamine, the chemical compounds enwrapped in the melamine-induced kidney stone samples differed from other kidney stone samples, providing useful hints for studying on the formation mechanisms of melamine-induced kidney stones. This study also provides useful information on establishing a MS-based platform for rapid analysis of the melamine-induced human kidney stones at molecular levels.     

表面解吸常压化学电离质谱快速分析六味地黄丸

采用新型表面解吸常压化学电离(Surface Desorption Atmospheric Pressure Chemical Ionization, SDAPCI)质谱法, 在敞开环境下, 对潮湿的空气进行电晕放电产生试剂离子, 进而在六味地黄丸表面发生解吸电离过程, 在无需复杂预处理的前提下对六味地黄丸中的待测物进行离子化, 从而获得了六味地黄丸在正负离子模式下的化学指纹图谱, 并利用主成分分析法对质谱指纹数据进行处理, 可对6个厂家生产的多个批次产品进行较好的区分. 结果表明, SDAPCI-MS技术能够快速测定六味地黄丸的剂型和生产厂家信息, 并能够对目标组分做多级串联质谱鉴定, 发现痕量目标组分. 研究方法可望应用于中成药药品生产质量控制和成品检测等领域.     

Desorption electrospray ionization mass spectrometry of intact bacteria

Desorption electrospray ionization (DESI) mass spectrometry (MS) was used to differentiate seven bacteria species on the basis of their measured DESI-mass spectral profile. Both gram-positive and gram-negative bacteria were tested and included Escherichia coli, Staphyloccocus aureus, Enterococcus sp., Bordetella bronchiseptica, Bacillus thuringiensis, Bacillus subtilis and Salmonella typhimurium. Distinct DESI-mass spectra, in the mass range of 50-500 u, were obtained from whole bacteria in either positive or negative ion modes in less than 2 mins analysis time. Positive ion DESI-mass spectral fingerprints were compared using principal components analysis (PCA) to investigate reproducibility for the intraday and the day-to-day measurements and the method selectivity to differentiate the bacteria studied. Detailed study of variances in the assay revealed that a large contribution to the DESI-mass spectral fingerprint variation was the growth media preparation procedure. Specifically, experiments conducted with the growth media prepared using the same batch yielded highly reproducible DESI-mass spectra, both in intraday and in day-to-day analyses (i.e. one batch of growth media used over a 3-day period versus a new batch every day over the same 3-day period). Conclusions are drawn from our findings in terms of strategies for rapid biodetection with DESI-MS.