An immune algorithm for resolution of multicomponent overlapping chromatograms

A novel immune algorithm for resolution and quantitative determination of the components in overlapping chromatograms was proposed by imitating biological immune systems. The algorithm takes an overlapping chromatogram as its input and subtracts the chromatograms of standard samples from the input by iteration of a network. When the residual does not change, the network will converge and chromatographic information of the components in overlapping chromatogram will be obtained. Both simulated and experimental data sets were investigated by the method. Results showed that both resolved results and recoveries of quantitative determination are satisfactory. Comparing with conventional least-square method, the immune algorithm is fast in calculation.     

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。     

An improved transmutation method for quantitative determination of the components in multicomponent overlapping chromatograms

An improved method is proposed for the quantitative determination of multicomponent overlapping chromatograms based on a known transmutation method. To overcome the main limitation of the transmutation method caused by the oscillation generated in the transmutation process, two techniques—wavelet transform smoothing and the cubic spline interpolation for reducing data points—were adopted, and a new criterion was also developed. By using the proposed algorithm, the oscillation can be suppressed effectively, and quantitative determination of the components in both the simulated and experimental overlapping chromatograms is successfully obtained.     

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。     

正交投影用于一维重叠色谱峰分辨及背景扣除

对于两组份色谱重叠峰体系,当以小组份色谱峰作为干扰时,本文利用正交投影方法,通过构造正交投影矩阵,利用原始信号及其投影与背景之间的内在关系来确定真实背景,从而将背景干扰予以扣除,使含背景干扰的一维重叠色谱峰得以分辨。模拟研究表明,对于两组份色谱峰重叠体系当以小色谱峰为干扰时本文方法具有很好的分辨效果,对于完全重叠峰,即使其峰分离度为零能得到满意的结果。     

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.     

小波变换用于色谱重叠峰的解析

利用小波变换的时频局部化性质，通过对色谱重叠峰信号小波变换后的某些频率段进行放大，使重叠谱峰得到了分离，并将此方法用于苯和甲苯二组分色谱体系的定量分析，重叠峰中各组分均得到了良好的线性关系及令人满意的定量分析。本文还讨论了不同小波基、分解的次数及放大系数在解析结果的影响。     

直观推导式演进特征投影法在拖尾重叠色谱峰解析中的应用

直观推导式演进特征投影法(HELP)已成功应用于复杂体系的重叠色谱峰解析.当色谱峰拖尾时,演进特征投影图(ELPG)显示的直线段对应的区域中可能含有前面拖尾组分的信息,据此进行HELP解析可能得不到满意结果.选择ELPG上直线段的一部分,即拖尾组分末端,前面组分的信息已基本消失的区域作为选择性区域进行HELP解析.同时,提出一种新的定量方法:用主成分分析法(PCA)分解待测组分标准样品的二维数据,将得到的“标准”色谱引入HELP的定量过程,在色谱峰拖尾或解得谱峰不平滑时,得到更准确的结果.用HELP方法解析了依诺沙星、诺氟沙星和环丙沙星三组分实验体系,结果表明,加入上述措施的HELP可有效改善拖尾重叠色谱峰的解析结果.     

Retention time alignment of LC/MS data by a divide-and-conquer algorithm

Liquid chromatography-mass spectrometry (LC/MS) has become the method of choice for characterizing complex mixtures. These analyses often involve quantitative comparison of components in multiple samples. To achieve automated sample comparison, the components of interest must be detected and identified, and their retention times aligned and peak areas calculated. This article describes a simple pairwise iterative retention time alignment algorithm, based on the divide-and-conquer approach, for alignment of ion features detected in LC/MS experiments. In this iterative algorithm, ion features in the sample run are first aligned with features in the reference run by applying a single constant shift of retention time. The sample chromatogram is then divided into two shorter chromatograms, which are aligned to the reference chromatogram the same way. Each shorter chromatogram is further divided into even shorter chromatograms. This process continues until each chromatogram is sufficiently narrow so that ion features within it have a similar retention time shift. In six pairwise LC/MS alignment examples containing a total of 6507 confirmed true corresponding feature pairs with retention time shifts up to five peak widths, the algorithm successfully aligned these features with an error rate of 0.2%. The alignment algorithm is demonstrated to be fast, robust, fully automatic, and superior to other algorithms. After alignment and gap-filling of detected ion features, their abundances can be tabulated for direct comparison between samples.     

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。     

Resolution of overlapped chromatograms by means of the kalmam filter : Data Processing of Liquid Chromatographic Signals without Solvent Peaks

If several samples are injected successively at short intervals into a liquid chromatograph, overlapped chromatograms of the samples will result. This paper describes an application of this successive-injection method to determination of samples without solvent peaks. Twenty peaks in the overlapped chromatograms resulting from five successive injections of samples with four components (phenetole, biphenyl, pyrene and perylene) were resolved and quantified by a reduced four-dimensional Kalman filter. The period of the single chromatogram of the four components is ca. 14 min, and the period of the five overlapped chromatograms ca. 26 min, for injection intervals of 3 min. The calibration lines for the four components are all straight and satisfactory; the slope, A, of every line was 1.005>A>0.9996 with correlation coefficients better than 0.999992. This successive-injection method with the reduced Kalman filter is time-saving for trivial routine work.     

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.     

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。     

Rapid Determination of Amino Acids in Ginseng by High Performance Liquid Chromatography and Chemometric Resolution

Ginseng is one of the most important traditional Chinese medicines and functional foods.A method for the fast determination of amino acids in ginseng samples using high performance liquid chromatography（HPLC） was developed,in which strong isocratic elution was employed for simplifying the separation and speeding up the analysis.All amino acids were eluted within 3 min with the chromatogram composed of overlapped peaks from the interferences.Then,non-negative immune algorithm（NNIA） was adopted to resolve the chromatographic signals of the components from the chromatogram measured.The results show that the signals of the amino acids can be correctly extracted by NNIA and the signal extracted can be used for the quantitative analysis.The method was validated via determining six amino acids of four different samples of ginseng.The recoveries of the spiked samples are in a range of 96.6％-106.3％.     

The use of simplex optimiztion in evaluating complex chromatograms of mixtures

The application of simplex optimization to the qualitative and quantitative evaluation of chromatograms of complex mixtures is outlined. The chromatogram is considered as a linear combination of pure component chromatograms (assuming no interactions are present); if suitable components are selected and the coefficients of the linear combination are properly evaluated, the experimental chromatogram can be reproduced numerically. The simplex method is then used to evaluate the solution with minimal error. The quantitation of polychlorobiphenyls from Aroclor mixtures in marine sediments and fish, and the identification of essential oils in a perfume base extract are outlined. Errors of ≤19% (25% in environmental samples) between the experimental and reconstructed chromatograms were achieved.     

Chemometric approach for fast analysis of prometryn in human hair by GC–MS

A method for the fast analysis of a specific component in complex samples by GC–MS was developed and used for the quantitative determination of prometryn in hair samples. In this method, the tedious and time‐consuming sample pretreatment for purification was avoided, and a short capillary column and fast temperature program were employed to speed up the analysis. Although the measured total ion chromatogram is composed of overlapping peaks with interference and background noise, the signal of prometryn can be extracted by chemometric methods. Window‐independent component analysis was used to extract the mass spectrum and a non‐negative immune algorithm was employed to obtain the chromatographic profile of the interesting component from the measured data. Due to the complexity of the matrix, a standard addition method was adopted for the quantification. The applicability of the method was validated with spiked samples, and the recoveries were in the range of 99–105%.     

离子色谱不对称色谱峰的处理

介绍了通过微分处理分辨离子色谱中不对称峰的方法。实验将Ｆ＾－、Ｃｌ＾－、Ａｃ＾－、ＮＯ２＾－、ＮＯ３＾－、ＰｈＣＯＯ＾－、ＳＣＮ＾－、柠檬酸根、水杨酸根、山梨酸根和葡萄糖酸根等常见离子按一定比例配合混合液,对出现的不对称峰进行微分处理,得到的导数谱图可进行峰高定量,收到了较好的效果。     

Software for Microprocessor Controlled HPLC: Peak Area Integration

Abstract

Programs are described for determination of peak areas and peak retention times from the chromatographic data obtained by a dual-microprocessor data handling microcomputer (DHC). The programs provide the necessary equipment testing and calibration routines for an accurate reproduction of a recorded chromatogram, and they are written to be merged with the data acquisition programs to provide a true “real-time” integrator. The integration is performed with baseline stabilization and automatic peak splitting. These features make the integrator applicable to gradient elution chromatography, as well as for the integration of complex chromatograms with overlapping peaks. The integrated chromatogram can be displayed with the limits of integration for each peak. Results of peak area integration of simple and complex chromatograms demonstrate satisfactorily accurate and consistant results that are independent of chromatographic conditions and shape of the peaks.     

Identification of Africanized honeybees

Gas chromatography and pattern recognition methods were used to develop a potential method for differentiating European honeybees from Africanized honeybees. The test data consisted of 237 gas chromatograms of hydrocarbon extracts obtained from the wax glands, cuticle, and exocrine glands of European and Africanized honeybees. Each gas chromatogram contained 65 peaks corresponding to a set of standardized retention time windows. A genetic algorithm (GA) for pattern recognition was used to identify features in the gas chromatograms characteristic of the genotype. The pattern recognition GA searched for features in the chromatograms that optimized the separation of the European and Africanized honeybees in a plot of the two or three largest principal components of the data. Because the largest principal components capture the bulk of the variance in the data, the peaks identified by the pattern recognition GA primarily contained information about differences between gas chromatograms of European and Africanized honeybees. The principal component analysis routine embedded in the fitness function of the pattern recognition GA acted as an information filter, significantly reducing the size of the search space since it restricted the search to feature sets whose principal component plots showed clustering on the basis of the bees' genotype. In addition, the algorithm focused on those classes and/or samples that were difficult to classify as it trained using a form of boosting. Samples that consistently classify correctly are not as heavily weighted as samples that are difficult to classify. Over time, the algorithm learns its optimal parameters in a manner similar to a neural network. The pattern recognition GA integrates aspects of artificial intelligence and evolutionary computations to yield a "smart" one-pass procedure for feature selection and classification.     

A novel determination of peak areas for application on large computers

Summary A computer program with some new algorithms for the determination of peak areas of gas chromatograms has been developed which has been used for several years with a satellite computer system. In contrast to most gc-programs the first and second derivatives of the curve are not used for peak detection. The maximum of a peak is defined by ordinates of the sample points alone; the base line is constructed by drawing curves of higher order through those parts of the chromatogram which are defined to be base line by special criteria. Consequently, the peak areas on the tailing of a solvent are determined more correctly than with skimming and, furthermore, the calculated base line of chromatograms with temperature program and subsequent isothermal run can be approximated to the real base line. The base line divides the chromatogram into several peak groups which are further separated by the democratic distribution method. This program is best suited for nonroutine analysis in research laboratories, because only a few input parameters are necessary for peak area determination with unknown chromatograms.