改进遗传算法用于未知组分数的重叠色谱峰的解析

按照指数修正的Gauss卷积色谱峰模型，构造了结合模拟退火及变长染色体的改进遗传算法，并结合爬山法，可以方便快捷地进行数目未知的重叠色谱峰的精确解析；此法成功地应用于大鼠脑微透析液氨基酸定量分析中，解析结果良好。     

径向基函数神经网络用于重叠色谱峰解析

 在高斯基径向基函数神经网络 (RBFNN)学习算法中引入了鲁棒性和随机全局寻优的两阶段遗传算法 :结构学习和参数优化。通过两阶段学习算法的交替使用 ,使网络具有结构自学习和参数优化的能力 ,而后将网络应用于组分数未知的重叠色谱峰解析。该方法具有不需人为干预 ,可自动确定网络结构即组分数的优点 ;并且解析精度较高 ,适用于多组分重叠色谱峰的解析 ;对完全重叠色谱峰也具有良好的解析能力。     

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。     

气相色谱-质谱法鉴定二氯丁烷异构体

利用气相色谱-质谱联用仪测试样品得到质谱图，按各峰强度及基峰质荷比等信息对化合物图谱进行解析，确定醚-三氯化铝体系中二氯丁烷异构体的结构。该法综合利用大型分析仪器分析同分异构体，较之利用标准品的传统方法更加省时、省力。     

固相微萃取-气相色谱-质谱法鉴定火场残留物中油漆稀释剂

对采用固相微萃取-气相色谱-质谱法从火场残留物样品中鉴定油漆稀释剂进行了研究。将火场残留物样品放入密闭的金属容器或塑料袋中,置于80℃烘箱加热20~30 min,在固相微萃取装置中用100μm聚二甲基硅氧烷纤维通过针头将密闭容器中的油漆稀释剂成分(此时已成气态)吸附,吸附时间为5~10 min,然后将纤维插入气相色谱进样口中解析进样,解析时间为2 min,按照预定的条件进行气相色谱-质谱分析。对气相色谱-质谱谱图上所得的峰进行分析,并与同条件下获得的油漆稀释剂试验样品气相色谱-质谱谱图进行比较,从而对油漆稀释剂作出定性鉴定。     

高效液相色谱/二极管阵列检测/质谱/质谱(HPLC/DAD/MS2)联用在板蓝根注射液成分鉴定中的应用

用HPLC/DAD/MS2联用仪,鉴定了板蓝根注射液中含有的核苷类物质。色谱条件:Luna C18 色谱柱(250 mm×4.6 mm i.d., 5 μm);甲醇-水梯度洗脱,流量0.8 mL/min; 柱温25 ℃。用二极管阵列检测器记录各个色谱峰的紫外吸收光谱,色谱检测波长254 nm。质谱条件:电喷雾离子源(ESI);正离子检测;扫描范围m/z 50-800。记录质量色谱图和各个色谱峰的一级、二级质谱图,并对质谱结果进行解析,通过与对照品比较,确定板蓝根注射液样品中含有腺苷、鸟苷、尿苷、胞苷及腺     

GC/FTIR数据的计算机解析—煤焦油洗油分析

本文提出了一个可以进行红外光谱解析和谱库检索的计算机程序。该解析程序将红外特征吸收频率、色谱保留指数和谱库检索结果三者结合起来,可迅速而准确地鉴定色谱峰,并能绘制出各色谱馏出物的吸收光谱图和谱库中最近似的参比光谱图,核对方便。当库存光谱数据资料中没有待检索的化合物时,仍能根据特征吸收频率和保留值数据作出较为正确的判断。此法用于分析煤焦油洗油馏份,可得到满意的解析结果。     

气相色谱-质谱法研究低分子量高含氢聚硅氧烷的组成

低分子量高含氢聚硅氧烷应用广泛,但组成复杂。实验建立了高含氢聚硅氧烷组成的分析方法。采用气相色谱质谱联用仪,对高含氢聚硅氧烷进行了分析,通过谱图解析和谱峰的规律性研究,共确定了样品中38个组分,包含有4组同系物:3种链状高含氢聚硅氧烷和1种环状高含氢聚硅氧烷。采用气相色谱方法对各组分进行了定量分析,研究结果对于改进生产工艺和提高低分子量聚硅氧烷的性能具有理论指导意义。     

高效液相色谱-质谱法分析菊芋叶中的绿原酸类化合物

建立了菊芋叶中绿原酸类化合物的高效液相色谱-紫外检测-质谱(HPLC-UV-MS)定性分析方法。液相色谱条件:Inertsil ODS-3色谱柱(250 mm×4.6 mm,5 μm);甲醇和水(含1%乙酸)梯度洗脱,流量1.0 mL/min;柱温35 ℃;检测波长327 nm。质谱条件:Thermo公司TSQ三级四极杆质谱仪;电喷雾电离(ESI)接口;负离子检出模式。采用该方法得到了菊芋叶提取物的紫外检测的色谱图、负离子监测的总离子流图以及相应色谱峰的紫外光谱图和一级、二级质谱图,对其进行解析,鉴别出菊芋叶中的7个绿原酸类成分。该方法简便、快速、灵敏度高,可以很好地对菊芋叶中的绿原酸类化合物进行定性分析。     

一种基于光谱分析的二元不完全重叠色谱峰的分离解析方法

基于二极管阵列检测器获得的色谱-光谱数据,建立了一种二元不完全重叠液相色谱峰的解析方法: 色谱数据经过去噪、归一化处理后,计算各时间点的光谱差异并进行系统聚类分析,提取特征光谱后,利用非负最小二乘法对色谱-光谱矩阵进行解析,得到基于特征光谱的流出曲线,进而得到分离后的色谱峰。将解析结果和纯标样的色谱峰进行比较,解析后的光谱图和纯标样的光谱图无显著差异,保留时间相差小于0.01 min。实验结果表明,该方法在二元不完全重叠液相色谱峰的解析方面能取得良好的效果。     

Application of chemometrics in homolog-specific analysis of polychlorinated biphenyls

A principal components multivariable statistical method based on SIMCA 3B (Soft Independent Method of Class Analogy) algorithms was evaluated and applied to interpretation of homolog-specific analysis of polychlorinated biphenyls by high resolution gas chromatography. High resolution gas chromatograms can be evaluated in high resolution separations of individual PCB isomers and grouped into the homologous series. The chromatograms show distinct differences between PCB compositions with different contents of chlorine atoms in technical mixtures (Aroclors). The objective of utilizing SIMCA 3B was its evaluation for a possible identification, classification, and categorization of Aroclors in environmental samples.     

Resolution of Overlapping Chromatographic Peaks Using a Genetic Algorithm

ABSTRACT

A genetic algorithm for resolution of overlapping chromatographic peaks (GAROCP) using real-number coding, non-uniform mutation and arithmetical crossover methods is described in this paper. It was applied to resolution of highly overlapped multicomponent high-performance liquid chromatographic peaks by fitting experimental chromatogram to the exponentially modified Gaussian (EMG) model. The genetic algorithm was used to find the minimum of fitting error to optimize the parameters in the EMG functions which determine the shape and area of each peak. The applicability of the method was investigated with both simulated signals calculated by EMG functions and experimental multicomponent overlapping chromatograms.     

Monolithic silica columns for high-efficiency chromatographic separations

A deconvolution methodology for overlapped chromatographic signals is proposed. Several single-wavelength chromatograms of binary mixtures, obtained in different runs at diverse concentration ratios of the individual components, were simultaneously processed (multi-batch approach), after being arranged as two-way data. The chromatograms were modelled as linear combinations of forced peak profiles according to a polynomially modified Gaussian equation. The fitting was performed with a previously reported hybrid genetic algorithm with local search, leaving all model parameters free. The approach yielded more accurate solutions than those found when each experimental chromatogram was fitted independently to the peak model (single-batch approach). The improvement was especially significant for those chromatograms where the peaks were severely affected by the tails of the preceding compounds. Peak shifts among chromatograms, which are a usual source of non-bilinearity, were modelled in a continuous domain instead of in a discrete way, which avoided some drawbacks associated with latent variable methods. An experimental design involving simulated chromatograms was applied to check the method performance. Five main factors affecting the deconvolution were examined: concentration pattern, chromatographic resolution, number of batches and replicates, and noise level, which were evaluated using first- and second-order figures of merit. The method was also tested on three real samples containing compounds showing different overlap. Four multi-batch deconvolution methods were considered differing in the nature of the processed information and kind of peak matching among chromatograms. In all cases, the multi-batch deconvolution yielded better performance than the single-batch approach.     

小波变换用于重叠色谱峰组分信息的提取

提出了一个小波变换用于提取重叠色谱中组分信息的理论公式，并将它应用于三组分和五组分重叠色谱实验数据的解析。结果表明：在定定分离度范围内，当相邻色谱峰峰宽相近时，根据此公式的计算结果，可以将各组分的信息从重叠色谱峰信号中提取出来。洒工作对小波变换用于重叠峰的解析具有重要意义。     

An algorithm for overlapped chromatogram separation

Non-negative matrix factorization (NMF) is a recently developed method for real time data analysis. In the past it has been used for facial recognition and spectral data analysis. Most of the NMF algorithms do not converge to a stable limit point and uniqueness in results is also a problem in NMF. To improve the convergence, a new NMF algorithm with modified multiplicative update (ML-NMFmse) has been proposed in this work for strongly overlapped and embedded chromatograms separation. To get same results for all the runs, instead of random initialization, three different initialization methods have been used namely, ALS–NMF (robust initialization), NNDSVD based initialization and EFA based initializations. The proposed ML-NMFmse algorithm is applied on the simulated and experimental overlapped chromatograms obtained for acetone and acrolein mixture, using Gas Chromatography–Flame Ionization Detector. Before applying NMF, Principal Component Analysis (PCA) was applied to determine number of components in the mixture taken. The result of proposed ML-NMFmse is compared with that of existing Multivariate Curve Resolution-Alternating Least Squares method in optimal conditions for both the algorithms. In the case of embedded chromatogram, the proposed ML-NMFmse with Robust method (ALS-NMF) of initialization performs better than all other methods. For a resolution of severely overlapped chromatograms, the proposed ML-NMFmse with NNDSVD method of initialization outperforms all other methods.     

一种新型的信号拟合方法--免疫算法

通过对免疫系统免疫机制的模拟,提出了一种新型的信号拟合算法。该算法根据所提供的标样信息对重叠分析化学信号进行拟合,从重叠信号中提取单一组分的信息,从而实现了多组分混合信号的解析。对模拟信号的实验信号的处理结果表明,该方法可方便地用于多组分重叠色谱信号的解析。     

一种新型的信号拟合方法─—免疫算法

通过对免疫系统免疫机制的模拟,提出了一种新型的信号拟合算法。该算法根据所提供的标样信息对重叠分析化学信号进行拟合,从重叠信号中提取单一组分的信息,从而实现了多组分混合信号的解析。对模拟信号和实验信号的处理结果表明,该方法可方便地用于多组分重叠色谱信号的解析。     

Longest distance shifting: A simple and efficient approach for the alignment of shifted chromatographic peaks

The preprocessing of chromatograms, such as the alignment of retention time shifts, is often a crucial step in the proper data analysis chain. Here, an efficient approach to align shifted chromatographic signals, longest distance shifting, is presented and highlighted. The performance of this novel strategy was demonstrated by using both simulated chromatograms that covered the different kinds of retention time shifts and the real experimental chromatograms of Pudilan Xiaoyan Tablets obtained by high‐performance liquid chromatography with photodiode array detection. The averaged correlation coefficient for experimental chromatograms were in the range of 0.9517–0.9840 and the peak factor was 0.9989. As a comparison, all the chromatograms have also been aligned using correlation optimized warping and Interval Correlation Optimized Shifting algorithms. The obtained results indicate that the longest distance shifting algorithm is simpler, faster and more effective, and will be potentially suitable for the alignment of other types of signals.     

The Short and Long of it: Shorter Chromatographic Analysis Suffice for Sample Classification During UHPLC-MS-Based Metabolic Fingerprinting

Ultra high-performance liquid chromatography hyphenated to mass spectrometry (UHPLC-MS) technologies has been widely applied in metabolomics, and the high resolution and peak capacity thereof are only some of the key aspects that are exploited in such and related fields. In the current study, we investigated if low resolution chromatography, with the aid of multivariate data analyses, could be sufficient for a metabolic fingerprinting study that aims at discriminating between samples of different biological status or origin. UHPLC-MS data from chemically-treated Arabidopsis thaliana plants were used and chromatograms with different gradient lengths were compared. MarkerLynx? technology was employed for data mining, followed by principal component analysis (PCA) and orthogonal projections to latent structure discriminant analysis (OPLS-DA) as multivariate statistical interpretations. The results showed that, despite the congestion in low resolution chromatograms (of 5 and 10 min), samples could be classified based on their respective biological background in a similar manner as when using chromatograms with better resolution (of 20 and 40 min). This paper thus underlines that, in a metabolic fingerprinting study, low resolution chromatography together with multivariate data analyses suffice for biological classification of samples. The results also suggest that, depending on the initial objective of the undertaken study, optimisation in chromatographic resolution prior to full scale metabolomics studies is mandatory.     

免疫算法用于多组分二维色谱数据的解析

通过对免疫系统抗体对抗原消除作用及其记忆功能的模拟,提出了解析二维数据矩阵的新方法。采用模拟的EMG公式作为抗体输入,对二维信号逐行进行迭代消除,从重叠峰中提取单一组分的色谱信息和光谱信息。通过对二维色谱数据的解析,结果表明,该方法可方便地用于多组分重叠二维色谱的解析。