直观推导式演进特征投影法解析多环芳烃的重叠色谱峰

用高效液相色谱法(HPLC)测定多环芳烃时,因芴、苊和菲,茚(1,2,3-cd)芘和苯并(g,h,i)苝的色谱峰严重重叠而影响测定结果。本研究用高效液相色谱-二极管阵列检测器(DAD)和荧光检测器(FLD)测定多环芳烃,在激发波长λex=230nm,发射波长λem=300～500nm范围内采集重叠峰的HPLC-FLD二维色谱数据,再用直观推导式演进特征投影法(HELP)解析它们的重叠色谱峰,分辨结果令人满意。该方法对重叠组分的分辨下限为0.02mg/L。结果表明,用二维色谱荧光数据解析色谱重叠峰,灵敏度更高,可用于环境样品中多环芳烃的测定。     

直观推导式演进特征投影法及其在复杂体系分析中的应用

对直观推导式演进特征投影法(HELP)的原理及主要步骤作了简要介绍。综述了HELP的研究情况及其在中草药分析、环境样品分析等领域中的应用，并对该法的优势和发展趋势作出了讨论。     

直观推导式演进特征投影法测定不同方法提取的国产血竭中龙血素B的含量

利用HPLC-DAD产生的二维数据和化学计量学方法-直观推导式演进特征投影法（HELP），解析了不同提取方法得到的国产血竭中的重叠色谱峰，并对其中的指标性成分-龙血素B进行了含量测定，结果满意。这表明这化学计量学方法与现代分析手段有机结合，将为中药等复杂体系的分析提供一条新途径。     

直观推导式演进特征投影算法-气相色谱-质谱联用测定烟叶中挥发性组分

应用气相色谱-质谱法及直观推导式演进特征投影(HELP)算法测定了烟叶中的挥发性组分.取经干燥及粉碎的烟叶样品用加速溶剂萃取法在160℃用乙醇提取15 min,所得提取液经吹氮蒸缩至1.5 mL,取1μL进样分析,采用DB-5MS毛细管柱进行分离.质谱分析采用电子轰击离子源,在质荷比(m/z)30～500范围内进行扫描...     

直观推导式演进特征投影法对酶催化反应的过程分析

以丁香酸(syringic acid)为模型化合物, 研究了漆酶(laccase)催化降解木质素(lignin)的复杂生化反应过程, 设计了一种反应过程动态量测系统, 该系统可以在5 s的时间间隔测定反应体系在190～800 nm波长范围内的实时光谱信息. 利用固定窗口因子分析-直观推导式演进特征投影法(FSMWEFA-HELP), 解析反应过程中测得的实时动力学光谱数据矩阵, 得到反应物和中间体的数目及其浓度的变化和纯物质的光谱曲线, 并推导出合理的反应机理. 将所得结果与多元曲线分辨-交替最小二乘(MCR-ALS)方法进行了比较.     

直观推导式演进特征投影法分辨枸杞类胡萝卜素的异构体

采用高效液相色谱-二极管阵列检测方法,初步分离了枸杞子中的类胡萝卜素。以乙腈-二氯甲烷(体积比为60∶40)为流动相,流速为1.0 mL/min,用C18柱从枸杞类胡萝卜素中分离出7个峰。但由于类胡萝卜素的结构多样性,尤其是顺反异构体的出现使得分离并不完全。利用所得三维数据提供的信息和化学计量学方法直观推导式演进特征投影法(HELP),对其中某些在二维色谱中被定性为单组分的峰进行解析,结果发现原来在二维色谱中被定性为单组分的峰大多是一些多组分峰。以其中第4个峰为例对其进行解析,得到了该类胡萝卜素的同分异构体色谱流出曲线及紫外光谱信息。该方法表明,化学计量学方法与现代分析手段有机结合,大大降低了此类复杂体系对色谱分离的要求,对同分异构体的分析具有一定的借鉴和指导意义。     

直观推导式演进特征投影法测定中药丹参中3种丹参酮含量

利用化学计量学方法直观推导式演进特征投影法和高效液相色谱(二级管阵列检测器)产生的二维数据,解析丹参药材中重叠色谱峰,并对其中的活性成分-丹参酮ⅡA、隐丹参酮和丹参酮Ⅰ进行测定。该方法能够快速测定复杂体系中药内的活性成分,显著提高分析效率。     

模差渐进投影法解析重叠色谱峰

提出了一种鉴别重叠色谱峰类型的化学计量学方法——模差渐进投影(MDEP)法。该方法利用二维色谱数据中相邻两个色谱流出点的光谱矢量模的和与该两个矢量和的模之差,建立模差-时间(dm-t)曲线判断非纯色谱峰的纯组分区,同时判定第二组分色谱流出点和倒数第二组分色谱结束点。分别以纯组分区的光谱矢量建立正交阵对该色谱峰进行投影运算,得到投影后转换色谱。该转换色谱消除了纯组分区所对应化合物的色谱和光谱信息。对转换色谱重复上述操作至整个色谱峰的模差-时间曲线均为0时终止,得到重叠色谱峰各组分的色谱流出点和结束点。利用上述结果,采用不包含待测组分光谱信息的该重叠峰二维色谱数据建立正交矩阵对该色谱峰进行投影运算,获得待测组分的相似色谱图。通过比对分析即可得到该组分在重叠色谱峰中的光谱和色谱信息。依次操作,即可获得重叠色谱峰中各组分的光谱和色谱信息。采用模差渐近投影法对4组分模拟重叠二维色谱峰及杜香挥发油GC-MS的重叠色谱峰进行了解析,方法简便、结果准确。     

中药丹参高效液相色谱重叠峰的解析

采用超临界CO2萃取方法对丹参中的脂溶性成分进行提取，利用高效液相等度分离方法对丹参脂溶性成分进行分离，再结合启发渐进式特征投影法和固定尺寸移动窗口渐进因子分析法对未能完全分离的重叠峰进行解析，得到了比较满意的结果。     

中药丹参高效液相色谱重叠峰的解析

采用超临界CO2萃取方法对丹参中的脂溶性成分进行提取,利用高效液相等度分离方法对丹参脂溶性成分进行分离,再结合启发渐进式特征投影法和固定尺寸移动窗口渐进因子分析法对未能完全分离的重叠峰进行解析,得到了比较满意的结果.     

Analysis of the Water Soluble Constituents of Cordyceps Sinensis With Heuristic Evolving Latent Projections

ABSTRACT

A chemometric technique, heuristic evolving latent projection (HELP), was applied to analyze the data obtained from high performance liquid chromatography coupled with the diode array detection (HPLC-DAD) for a traditional Chinese medicinal herb, Cordyceps sinensis. Based on this method, the water soluble components, nucleosides in Cordyceps sinensis were identified. Ten and eleven volatile components were identified from the fungal and larvae parts of Cordyceps sinensis sample, respectively. As compared with the conventional method, HELP was found to be suitable for quantitative analysis of complex real systems such as Chinese medicinal products.     

多元曲线分辨等方法和红外光谱用于二硝基五亚甲基四胺的合成反应机理研究

通过红外光谱在线监测强酸催化下硝酰胺、甲醛和氨水合成二硝基五亚甲基四胺(DPT)的反应过程, 利用渐进因子分析(EFA)、直观推导式演进特征投影法(HELP)和多元曲线分辨-交替最小二乘法(MCR-ALS)等化学计量学方法对反应过程获得的红外光谱信息进行解析, 得到了各组分纯物质的浓度变化曲线和对应的红外光谱, 并把多元曲线分辨-交替最小二乘法与直观推导式演进特征投影法的分析结果进行比较, 得出可相互验证的一致结论, 以此推测出该反应合理的反应机理. 化学计量学方法对在线红外光谱信息的分辨可以快速有效地反映DPT合成过程中各组分的浓度和红外光谱变化情况, 对其反应机理研究具有重要指导意义.     

Resolution of Overlapped Capillary Electrophoresis Peaks by Using Heuristic Evolving Latent Projections to Quantify Chloroquine Phosphate and Promethazine Hydrochloride

Chloroquine phosphate and promethazine hydrochloride are two main components in compound reserpine tablets. It is difficult to separate the two compounds with capillary electrophoresis (CE). Heuristic evolving latent projections (HELP) is a chemometric algorithm which is suitable for resolving overlapped peaks from CE and HPLC. In this paper, HELP was applied to resolving the completely overlapped peaks of chloroquine phosphate and promethazine hydrochloride from CE. Mathematical separation and satisfactory quantification results can be achieved easily without too much time involved in the procedure.     

Comparison of the volatile constituents of different parts of Cortex magnolia officinalis by GC‐MS combined with chemometric resolution method

Volatile compositions of different parts (stem, branch and root barks) of Cortex magnolia officinalis, cultivated in China, were investigated for the first time by GC‐MS with the help of heuristic evolving latent projection (HELP). Identification of components was conducted by similarity matching to NIST mass library but also assisted by comparison of temperature‐programmed retention indices (PTRIs) with the data web available. A total of 90, 82 and 76 volatile compounds in the essential oils of the three samples taken from the same batch aforementioned were qualitatively and quantitatively determined, representing 84.03, 83.68 and 83.10% of the total content, respectively. Among the constituents determined, there were 50 components coexisting. Eudesmol and its isomers were shown to be the principal compounds in the studied samples, accounting for 47.66, 36.74 and 36.31%, respectively. The three kinds of isomers (α‐, β‐ and γ‐eudesmol) in houpo volatile oils have been tentatively qualified and quantified simultaneously for the first time. By comparative analysis, significant qualitative and semi‐quantitative differences and similarities were observed among the three samples. The results achieved provide a scientific evidence for further exploitation of Magnolia bark and clinical medication.