Translation Modification Iteration for Resolution and Quantification of Overlapping Chromatographic Peaks

A novel algorithm, translation modification iteration (TMI), is proposed for resolving overlapping chromatographic peaks. By this method, a series of similar peaks are obtained from the initial construction of single component peaks and approach the profiles of real single component peaks by iteration. Both simulated and experimental data are investigated with TMI, consequently overlapping peaks can be resolved into reasonable single component peaks easily and efficiently. Quantitative analysis is also successfully achieved in both simulated and experimental data, and the quantitative results obtained from TMI are superior to those obtained from perpendicular drop (PD) and tangent skim (TS) methods. Without too much time devoted to the procedure, TMI is a simple and practicable method for resolution and quantification of overlapping chromatographic peaks.

     

免疫算法: 一种新的多组分重叠色谱信号的解析方法

色谱及其联用技术的快速发展使其成为复杂样品分析的重要手段,但在复杂样品分析中仍难以避免多组分色谱信号的重叠。化学计量学利用数学方法对复杂重叠信号进行解析,为复杂样品的色谱分析提供了新的手段。本文对免疫算法研究的近期进展进行了总结,并以具体的实例介绍了其在多组分重叠色谱信号解析方面的应用。     

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。     

Resolution of the Embedded Chromatographic Peaks by Modified Orthogonal Projection Resolution and Entropy Maximization Method

ABSTRACT

The embedded chromatographic peaks usually can not be completely resolved by conventional multivariate resolution methods. The resolution condition of a certain component in two-way data is first reviewed. A modified orthogonal projection resolution (OPR) algorithm and new entropy maximization (EM) method are then proposed to resolve embedded chromatographic peaks in this paper. The modified OPR algorithm performs more precisely than conventional orthogonal projection resolution algorithm in resolving the chromatography of minor peak. The entropy criterion defined on the differential chromatography could obtain an approximate solution in resolution of the major chromatographic peak. Simulated and real data show that the modified OPR and entropy maximization (EM) methods perform well in solving the embedded problem.     

遗传算法在色谱谱图解析中的应用

将遗传算法引入色谱峰解析程序 ,结合色谱峰EMG模型及峰形经验公式 ,实现了恒温色谱谱图的全自动解析。对模拟谱图和实验谱图进行了解析 ,取得了满意的结果。本文对遗传算法的运算控制及运算效率进行了研究和讨论     

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。     

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。     

三元重叠色谱峰面积的定量方法

本从色谱峰的ＥＭＧ模型出发，通过对重叠色谱峰的模拟和回归分析，提出了一种三元重叠色谱峰的面积的定量方法，三元重叠色谱峰的每一个峰面积可以由峰面积比和总面积求得，此法所需的数据都由实验色谱图上测得，峰面积计算结果的相对误差小于±５％，适用于相对峰谷为５０％－９５％的三元重叠色谱峰面积的定量。     

A novel strategy on the spectrochromatographic analysis of a quaternary mixture by parallel factor analysis model

Poor chromatographic resolution is one of the main challenges in chromatographic analysis. Partially separated chromatographic peaks frequently occur, due to the nature of analytes and the demand for fast analysis using high flow rates and shorter columns. Modeling of chromatographic three-way data using suitable chemometric tools enables determining co-eluted peaks without using additional experimental efforts. In this paper, parallel factor analysis (PARAFAC) was applied to chromatographic data for the quantitative resolution of a quaternary mixture at the co-elution condition of acetaminophen, aspirin, ascorbic acid, and guaifenesin in a spectrochromatogram. The spectrochromatograms of the calibration set, validation set, and real samples were arranged as a three-way array. In the next step, the PARAFAC model was implemented to decompose the spectrochromatographic array into trilinear components, corresponding to spectral, chromatographic, and relative concentration profiles of the analytes. The chromatographic and spectral modes were used for the qualitative analysis of components, whereas the analytes in commercial tablets were quantified from their individual profiles in their concentration mode. This study indicated that the application of the PARAFAC model provided a novel strategy for determining overlapping peaks in a chromatogram to perform the analysis of multicomponent mixtures with reduced runtime and without additional efforts.     

分解色谱重叠峰的参数契合法

本文研究了色谱重叠峰一阶导数曲线中各极值点的相对位置与重叠子峰面积比之间的关系，提出了一种模式参数契合的色谱重叠峰分解方法，它在准确性方面优于传统的垂线法，在速度方面优于模型拟合法，可用于实时快速处理。     

Rapid analysis of multicomponent pesticide mixture by GC-MS with the aid of chemometric resolution

Applications of hyphenated chromatographic techniques, especially GC-MS technique, have been reported in chemical, biological, environmental, agricultural and medical analysis. The complexity of the samples in these fields is still an obstacle for the technique to be practical and the overlapping of the multicomponent signals induces chemometric methods widely employed. In this work, taking the rapid analysis of pesticide mixture as an example, a chemometric approach was proposed for resolution of multicomponent overlapping GC-MS signal. In the method, a mass spectral library of pesticides was organized at first, then target factor analysis (TFA) was employed for testing the existence of a specific pesticide in the multicomponent overlapping GC-MS signal, and finally the chromatographic information of the pesticide was extracted by a non-negative immune algorithm (IA). A GC-MS signal of a 40-component pesticide mixture eluted within 9 min was analyzed by the method. It was found that the mass spectra and chromatographic profiles of almost all the pesticides can be obtained.     

基于高通量解析算法的复杂样品重叠气相色谱-质谱信号的快速分析

化学计量学算法为重叠气相色谱-质谱(GC-MS)信号的解析提供了有效手段,但其在计算过程中一般需要将数据进行分段处理,然后只对信号的某些区间进行解析,难以实现真正意义上的高通量分析。该文结合移动窗口目标转换因子分析(MWTTFA)和非负免疫算法(NNIA),建立了一种高通量解析方法。首先,根据所有可能存在的目标组分的标准质谱信息,利用MWTTFA检验复杂信号中存在的组分,并确定目标组分的质谱信息和洗脱时间区域。以得到的质谱信息作为后续计算的输入值,利用NNIA解析得到相应的色谱信息。采用快速升温程序对17种和42种农药混合标准样品的GC-MS信号进行分析,利用所建立的方法可在10 min内得到全部组分的色谱和质谱信息。     

Nested genetic algorithm for resolving overlapping spectra

A nested genetic algorithm, including a genetic parameter level and a genetic implemented level, has been proposed and applied for resolving simulated overlapping spectra. Parameters of genetic algorithms (GA) were optimized by use of the genetic parameter level. The number of overlapping peaks was, moreover, detected simultaneously. Parameters of individual peaks in multiplets were computed by use of the genetic implemented level. It is obvious that the parameters of GA can be optimized and the number of overlapping peaks can be detected by itself. The optimization results are less affected than in traditional curve-fitting by the initial values of the parameters of the overlapping bands. Consequently, the nested genetic algorithm is superior to the curve-fitting technique for resolution of overlapping peaks.     

Application of time-domain differentiation of chromatographic peaks in liquid chromatography

The differentiation of chromatographic bands with respect to time is useful for improving the resolution of overlapping peaks owing to the reduced band widths of derivatives in comparison with the original bands. An IBM XT 286 microcomputer was interfaced to a Perkin-Elmer liquid chromatographic system and software was developped to allow the acquisition and digitization of chromatographic data for subsequent manipulation, storage and graphical representation. Smoothing and differentiation of chromatographic bands with respect to time were done by the Savitzky-Golay method. The method was applied to the determination of a mixture of antioxidants used as additives in nutrition. The overlapping peaks corresponding to propyl gallate and tert-butylhydroquinone were resolved by time-domain differentiation.     

小波包分析用于重叠分析化学信号的处理

对小波包分析的算法进行了改进,并将此算法成功地应用于多组分重叠色谱信号的解析.结果表明,本文提出的算法解决了MRSD算法的不足,更适合处理分析化学信号,用于重叠信号的解析时不需重构(逆变换),简化了数据处理步骤,加快了数据解析速度,具有较强的解析能力.对于重叠色谱信号的解析,小波包分析比小波分析具有更强的解析能力.     

Resolving batch chromatographic overlapping peaks of flavoring essence using stepwise key spectrum selection

Stepwise key spectrum selection (SKSS) was introduced to resolve batch overlapping peaks from gas chromatography-mass spectrometry (GC-MS) analysis of ten batch tobacco flavoring samples in different storage times. Resolution was implemented on a software platform that embedded the SKSS method. The data from GC-MS analysis of the samples were saved and prepared in ASCII files and then were inputted into the software platform for visual inspections. The data segment with overlapping peaks was precut for subsequent analysis. Spectral background in the data was removed using a linear fitting of the baseline. Four components in the overlapping peaks were automatically detected by the SKSS method. The resolution of the concentration profiles and spectra of the four components was conducted by setting only one parameter, the negative area ratio, as 0.01. The fixed size moving window evolving factor analysis and evolving factor analysis were applied to validate the resolved concentration profiles. The resolved mass spectra were validated by the searched standard through library search at the pure component regions revealed by the resolved concentration profiles. The results showed that the SKSS method could be a simple but powerful tool in resolving batch chromatographic overlapping peaks.     

High-throughput approach for analysis of multicomponent gas chromatographic–mass spectrometric signals

Hyphenated techniques such as gas chromatography–mass spectrometry (GC–MS) or high-performance liquid chromatography–mass spectrometry (LC–MS) produce a large amount of data in a form of two-way data matrix. It has been a great challenge to furthest extract the useful information from the data. In this work, a chemometric approach based on a modification of adaptive immune algorithm (AIA) was proposed for a high-throughput analysis of the multicomponent overlapping GC–MS signals. With the proposed method, the chromatographic profile of each component in an overlapping signal can be extracted independently and sequentially along the retention time. In order to show the efficiency of the method, a stimulated GC–MS data of six components with background and an experimental GC–MS data of 40 pesticides were investigated. It was found that the multicomponent overlapping GC–MS signals could be fast and accurately resolved. Furthermore, the quantitative property of the extracted information was also investigated. The correlation coefficients (r) between the peak area and the added volumes of the sample are in the range 0.9658–0.9953.     

Linear Modulated Stochastic Resonance Algorithm Applied to Determination of Thidiazuron Residue in Water Using Stochastic Resonance

Abstract

The newly proposed linear modulated stochastic resonance algorithm (LSRA) was used to amplify and detect the weak chromatographic peaks of thidiazuron. The output chromatographic peak is often distorted when using the traditional stochastic resonance algorithm because of the existence of strong noise. In LSRA, the distortion of the output peak can be corrected by introducing a linear force into the nonlinear system. A two‐step optimization method was proposed to give attention to both the signal‐to‐noise ratio and the peak shape of output signal. The weak chromatographic peaks of thidiazuron can be amplified significantly and the distortion of the output peaks can be corrected using LSRA. The algorithm was used to detect thidiazuron residue in water with solid phase extraction‐high performance liquid chromatography. The limit of detection and limit of quantification were improved to 2.5 ng/l and 10 ng/l, respectively.     

Direct Chiral Liquid Chromatographic Separation of Tocainide Enantiomers on a Crownpak (Cr) Column and its Application to Pharmaceutical Formulations and Biological Fluids

Abstract

Direct chiral liquid chromatographic resolution of racemic tocainide was accomplished without any derivatization using a crownpak CR(+) column as a chiral stationary phase. The stereochemical resolution (R) with symmetrical peaks was 0.97 and a separation factor (α) of 1.44 were obtained. Optimization of separation was achieved using different concentrations of perchloric acid.     

正交投影用于多波长色谱重叠峰分析

 将正交投影分辨 (OPR)技术用于多波长色谱重叠峰分辨 ,当色谱峰中最大重叠度小于或等于波长数时 ,用这一方法能从多波长色谱重叠峰中获得完全真解。基于双波长色谱分析 ,提出了一种新的色谱重叠峰中背景校正、组分数和纯组分信号区确定以及各组分重叠情况的分析方法 ,即双波长特征信息分析 (DWCI)。该法被成功的用于三组分双峰和双组分单峰重叠色谱的分析。