中药色谱指纹图谱组分保留时间漂移的校准

基于光谱相关色谱方法判断复杂中药色谱指纹图谱的组分相关性,实现同一中药样本在不同实验条件下所得的色谱指纹图谱的相同组分的色谱保留时间漂移的局部最小二乘校正,为合理评价指纹图谱的品质提供较为实用的工具。     

多组分光谱相关色谱及其在中药色谱指纺图谱分析中的应用

基于正交投影理论和相关色谱方法提出多组分光色谱方法提出多组分光谱相关 色谱。为克服联用色谱仪器的不等性噪声影响，采用目标组分投影前后的光谱夹角 余弦判据，判断不同的中药色谱指纹图谱的相关组分色谱峰簇。该方法为中药指纹 图谱的数据处理、合理评价以及中药谱效学的基本理论研究提供一种实用的工具。     

Quality evaluation of fingerprints of herbal medicine with chromatographic data

In this study, local least squares (LLS) and principal component analysis (PCA) were applied to deal with the disturbances in a data set of chromatographic fingerprints after necessary data transformations. It has been demonstrated that PCA with standard normal variate (SNV) transformation of data led to meaningful classification of 33 different Erigeron breviscapus herbal samples. The result was also corroborated by variance squares discriminant method. The quality of herbal objects was further evaluated, and the causes of this fact have been explained from a chemical point of view. At the same time, it implied an idea for qualitative evaluation of the herbal objects with a common class pattern of chromatographic fingerprints.     

Spectral correlation of high-performance liquid chromatography-diode array detection data from two independent chromatographic runs peak tracking in pharmaceutical impurity profiling

A novel qualitative analytical method for peak tracking in impurity profiling control by the correlation of spectra was established. Two-dimensional (2D) standard spectrochromatographic data produced by high-performance liquid chromatography with diode array detection (HPLC-DAD) were compared with sample data to develop two-dimensional chromatographic spectral correlative maps. Taking full advantage of separation efficiency of HPLC and spectral specificity of the analytes, the method was successfully used to recognize impurities in quinolone antibacterials, when in combination with relative retention times (RRTs). For the comparison of spectra was expanded to three-dimensional space, simultaneous identification of the chromatographic peaks can be obtained rapidly without preparation and injection of a reference solution, even when the mobile phase changed or the peaks of multi-component samples overlapped.     

Alternative moving window factor analysis for comparison analysis between complex chromatographic data

In this investigation, a novel chemometric method is developed for the analysis of five possible relationships of components or spectral features between two correlative but different hyphenated chromatographic systems. It is very helpful for comparison study of components present in different complex systems in both chemistry and systems biology. The proposed method, named alternative moving window factor analysis (AMWFA), could be utilized to determine the number of common components between different samples and then to identify their corresponding spectra half-automatically. AMWFA can alternatively be employed to mind for the selective information hiding in anyone of the two compared data X and Y, and to self-verify the resolution results by changing the extracted target matrices in analysis. From the results of comparison of simulated hyphenated chromatographic data, volatile chemical components in drug pair rhizoma ligustici chuanxiong-radix paeoniae rubra (RLC-RPR) and its single herbal medicines, and analysis of Angelica oral solution and its plasma sample after oral intake to rabbit, powerful ability of the proposed method is shown.     

Modified secured principal component regression for detection of unexpected chromatographic features in herbal fingerprints

Secured principal component regression is modified for the qualitative analysis of chromatographic fingerprint data sets of herbal samples with residual concentrations. After chromatographic shift-correction and autoscaling are performed on the data, this modified secured principal component regression (msPCR) can detect unexpected chromatographic features in various herbal fingerprints. The successful application of msPCR to two real herbal medicines of Erigeron breviscapus from different geographical origins and Ginkgo biloba from various sources or vendors demonstrates that the proposed method can detect reasonably unexpected features differing from the regulars or not being modeled. From a chemical point of view, the causes have also been explained to corroborate the results. Moreover, it presents a viable approach for the qualitative evaluation of diverse herbal objects with a regular class of chromatographic fingerprints.     

Fingerprint developing of coffee flavor by gas chromatography-mass spectrometry and combined chemometrics methods

In this paper, chromatographic fingerprint was firstly used for quality control of tobacco flavors. Based on gas chromatography-mass spectrometry (GC-MS) and combined chemometrics methods, a simple, reliable and reproducible method for developing chromatographic fingerprint of coffee flavor, one of tobacco flavors, was described. Six coffee flavor samples obtained from different locations were used to establish the fingerprint. The qualitative and quantitative analysis of coffee flavor sample from Shenzhen was completed with the help of subwindow factor analysis (SFA). Fifty-two components of 68 separated constituents in coffee flavor sample from Shenzhen, accounting for 88.42% of the total content, were identified and quantified. Then, spectral correlative chromatography (SCC) was used to extract the common peaks from other five studied coffee flavor samples. Thirty-eight components were found to exist in all six samples. Finally, the method validation of fingerprint analysis was performed based on the relative retention time and the relative peak area of common peaks, sample stability and similarity analysis. The similarities of six coffee flavor samples were more than 0.9104 and showed that samples from different locations were consistent to some extent. The developed chromatographic fingerprint was successfully used to differentiate coffee flavor from coco flavor and some little difference sample prepared with coffee flavor and coco flavor by both similarity comparison and principal component projection analysis. The developed method can be used for quality control of coffee flavor.     

Application of combined approach to analyze the constituents of essential oil from Dong quai

A combined approach of sub-window factor analysis and spectral correlative chromatography has been employed to analyze the constituents of essential oils of Dong quai. Essential oils are the main pharmacological active individuals of Dong quai. Some constituents in the main root of Dong quai have been identified by GC-MS with the help of sub-window factor analysis resolving two-dimensional original data into mass spectra and chromatograms. Correlative constituents in another part of the root fiber have been recognized by spectral correlative chromatography. Seventy six of 97 separated constituents in the essential oil of main root were identified and quantified, accounting for about 91.36% of the total content. Sixty seven correlative components in the essential oil of root fiber were recognized. The result proves that the combined approach is powerful enough for the analysis of complex herbal samples.     

Classification of high-speed gas chromatography-mass spectrometry data by principal component analysis coupled with piecewise alignment and feature selection

A useful methodology is introduced for the analysis of data obtained via gas chromatography with mass spectrometry (GC-MS) utilizing a complete mass spectrum at each retention time interval in which a mass spectrum was collected. Principal component analysis (PCA) with preprocessing by both piecewise retention time alignment and analysis of variance (ANOVA) feature selection is applied to all mass channels collected. The methodology involves concatenating all concurrently measured individual m/z chromatograms from m/z 20 to 120 for each GC-MS separation into a row vector. All of the sample row vectors are incorporated into a matrix where each row is a sample vector. This matrix is piecewise aligned and reduced by ANOVA feature selection. Application of the preprocessing steps (retention time alignment and feature selection) to all mass channels collected during the chromatographic separation allows considerably more selective chemical information to be incorporated in the PCA classification, and is the primary novelty of the report. This methodology is objective and requires no knowledge of the specific analytes of interest, as in selective ion monitoring (SIM), and does not restrict the mass spectral data used, as in both SIM and total ion current (TIC) methods. Significantly, the methodology allows for the classification of data with low resolution in the chromatographic dimension because of the added selectivity from the complete mass spectral dimension. This allows for the successful classification of data over significantly decreased chromatographic separation times, since high-speed separations can be employed. The methodology is demonstrated through the analysis of a set of four differing gasoline samples that serve as model complex samples. For comparison, the gasoline samples are analyzed by GC-MS over both 10-min and 10-s separation times. The successfully classified 10-min GC-MS TIC data served as the benchmark analysis to compare to the 10-s data. When only alignment and feature selection was applied to the 10-s gasoline separations using GC-MS TIC data, PCA failed. PCA was successful for 10-s gasoline separations when the methodology was applied with all the m/z information. With ANOVA feature selection, chromatographic regions with Fisher ratios greater than 1500 were retained in a new matrix and subjected to PCA yielding successful classification for the 10-s separations.     

Triterpenoids from swallow roots--a convenient HPLC method for separation

A convenient semi-preparative high-performance liquid chromatography (HPLC) method for separating a mixture of triterpenoids (alpha-amyrin, beta-amyrin, and lupeol) and their corresponding acetates from the swallow roots (Decalepis hamiltonii Wight and Arn), which are known to have potential bioactive properties, is described. The swallow roots are found to be one of the richest natural sources for these compounds. The hexane extract of the dried spent root on column chromatography yields mixtures (i.e., triterpenoids and their acetates) containing at least three compounds in each. These could not be further separated using the routine chromatographic techniques, such as classical column chromatography and preparative thin-layer chromatography using various solvent systems. Therefore, the optimal conditions are determined on reversed-phase HPLC for their separation and are characterized using spectral data, particularly by nuclear magnetic resonance with physical and chemical properties.     

A new algorithm of piecewise automated beam search for peak alignment of chromatographic fingerprints

The alignment of chromatographic signals is an important preprocessing step before further multivariate analysis. This paper presents a method, automated peak alignment by beam search (Auto-PABS), to solve the problem of peak shift in chemical chromatographic fingerprints by piecewise shifting and linearly interpolating. It is characterized by searching an adaptive range for the values of shifting and linearly interpolating of each segment. This search range is estimated by the calculation of fast Fourier transform cross correlation between the sample segment and its corresponding reference segment. Thus, arbitrary peak alignment is avoided when the real peak shifts are unknown in a large data set. Since the maximum of search range is close to the real shift, more accurate beam search is adopted to accomplish the optimization process. Simulated data and herbal medicine fingerprints of HPLC and GC are selected for evaluation. The output matrix of aligned chromatographic profiles is used directly for principal components analysis, yielding satisfactory results on real samples.     

Correction of retention time shifts for chromatographic fingerprints of herbal medicines

In this study, the combination of chemometric resolution and cubic spline data interpolation was investigated as a method to correct the retention time shifts for chromatographic fingerprints of herbal medicines obtained by high-performance liquid chromatography-diode array detection (HPLC-DAD). With the help of the resolution approaches in chemometrics, it was easy to identify the purity of chromatographic peak clusters and then resolve the two-dimensional response matrix into chromatograms and spectra of pure chemical components so as to select multiple mark compounds involved in chromatographic fingerprints. With these mark components determined, the retention time shifts of chromatographic fingerprints might be then corrected effectively. After this correction, the cubic spline interpolation technique was then used to reconstruct new chromatographic fingerprints. The results in this work showed that, the purity identification of the chromatographic peak clusters together with the resolution of overlapping peaks into pure chromatograms and spectra by means of chemometric approaches could provide the sufficient chromatographic and spectral information for selecting multiple mark compounds to correct the retention time shifts. The cubic spline data interpolation technique was user-friendly to the reconstruction of new chromatographic fingerprints with correction. The successful application to the simulated and real chromatographic fingerprints of two Cortex cinnamomi, fifty Rhizoma chuanxiong, ten Radix angelicae and seventeen Herba menthae samples from different sources demonstrated the reliability and applicability of the approach investigated in this work. Pattern recognition based on principal component analysis for identifying inhomogenity in chromatographic fingerprints from real herbal medicines could further interpret it.     

Chemical fingerprint analysis for quality assessment and control of Bansha herbal tea using paper spray mass spectrometry

Chemical fingerprinting methodology is an approach for quality assessment and control of herbal medicines and related products based on the holistic chemical profile obtained by various analytical techniques. This study demonstrates the first application of paper spray mass spectrometry (PS-MS) as a chemical fingerprinting methodology for tracing the origins, establishing the authenticity, and assessing the overall quality of a famous herbal product, Bansha herbal tea (BHT). A negative ion PS-MS spectrum yielded the best chemical profiling information and was most appropriate for fingerprint analysis of BHT. In addition to the identification of active ingredients, various compounds present in BHT were simultaneously detected without any sample pretreatment and chromatographic separation, providing valuable information for the quality assessment and control of this herbal product. According to the principal component analysis of the PS-MS fingerprints, two sources of commercially available BHT products made by different manufacturers were easily differentiated. Qualified and expired products from the two manufacturers were also successfully distinguished, and the consistency of the quality between the manufacturers was assessed. Our experimental data demonstrated that the PS-MS chemical fingerprinting is a simple, rapid, and robust methodology for pharmaceutical analysis, with promising prospects for quality assessment and control of herbal medicines and related products with high-throughput.     

Metabolite Fingerprinting Based on 1H-NMR Spectroscopy and Liquid Chromatography for the Authentication of Herbal Products

Herbal medicines (HMs) are regarded as one of the traditional medicines in health care to prevent and treat some diseases. Some herbal components such as turmeric and ginger are used as HMs, therefore the identification and confirmation of herbal use are very necessary. In addition, the adulteration practice, mainly motivated to gain economical profits, may occur by substituting the high price of HMs with lower-priced ones or by addition of certain chemical constituents known as Bahan Kimia Obat (chemical drug ingredients) in Indonesia. Some analytical methods based on spectroscopic and chromatographic methods are developed for the authenticity and confirmation of the HMs used. Some approaches are explored during HMs authentication including single-component analysis, fingerprinting profiles, and metabolomics studies. The absence of reference standards for certain chemical markers has led to exploring the fingerprinting approach as a tool for the authentication of HMs. During fingerprinting-based spectroscopic and chromatographic methods, the data obtained were big, therefore the use of chemometrics is a must. This review highlights the application of fingerprinting profiles using variables of spectral and chromatogram data for authentication in HMs. Indeed, some chemometrics techniques, mainly pattern recognition either unsupervised or supervised, were applied for this purpose.     

色谱数据可视化及天然植物药指纹特征发现方法

提出一类色谱分析数据可视化方法,并用于发现天然植物药的化学指纹特征。选取中药材川芎作为典型研究对象,采用核主成分分析和空间投影变换法对色谱分析数据进行预处理,提取特征信息,再利用二维灰度映像对变换后的数据进行可视化表达,发现其化学指纹特征,从而直接反映出药材质量类别间的化学模式差异。将该方法用于辨识34个不同产地及等级的川芎样品,结果令人满意,证明其具有视觉模式分辨优点,是表达隐含特征指纹和辨识复杂化学物质体系的有力工具。     

t检验法用于评价中药色谱指纹图谱的相似度

本文采用t检验法评价中药色谱指纹图谱的相似度。利用来自六个不同厂家的三黄片样品的高效液相色谱指纹图谱数据来验证t检验法的适用性,并用主成分分析(PCA)进一步验证方法的可行性。在PCA的聚类图上,t检验无显著性差异的样品聚为一类,t检验有显著性差异的样品各为一类。结果表明:用t检验法能客观地反映中药样品间的相似性和差异性。     

Simultaneous determination of psoralen and isopsoralen in plasma and Chinese medicine Xian Ling Gu Bao capsule by using HPLC-DAD coupled with alternating trilinear decomposition algorithm

A method using high performance liquid chromatography with photodiode-array detection (HPLC-DAD) coupled with alternating trilinear decomposition (ATLD) algorithm was proposed for simultaneous determination of psoralen and isopsoralen in plasma and Chinese medicine “Xian Ling Gu Bao” capsule (XLGBC). In this paper, the application of ATLD algorithm into traditional chromatographic method can handle this problem that the chromatographic and spectral peaks are heavily overlapped among the analytes and even between the analytes and interferences from the background matrices. A simple improvement of chromatographic condition like mobile phase is not enough to realize effective separation for the two isomeric compounds, especially in the presence of interferences. However, the ATLD algorithm utilized “mathematical separation” instead of partial “physical or chemical separation” to directly determine the spectral profiles of the analytes of interests in complex system. The satisfactory quantification results have been gained with simple mobile phase. In the analysis of real Chinese medicine samples, the accuracy of the concentrations which were obtained by ATLD was also validated by HPLC-MS method.     

Information theory applied to chromatographic fingerprint of herbal medicine for quality control

At present, the construction of chromatographic fingerprints plays an important role in the quality control of complex herbal medicines. In this work, information theory was applied to obtain chromatographic fingerprints with good performance. Moreover, according to the characteristics of the chromatographic fingerprints obtained, some modifications of the calculation of the information content were conducted. In comparison with the information content from several chromatographic fingerprints obtained, reliable chromatographic fingerprints with a high separation degree and uniform concentration distribution of chemical components could be determined. The successful application of information theory with modification to simulated chromatographic fingerprints together with real herbal medicines such as Rhizoma chuanxiong and Ginkgo biloba from different sources demonstrated clearly that the proposed method to determine chromatographic fingerprints was reasonable and reliable and it was user-friendly. Chromatographic fingerprints determined with high separation degrees and uniform concentration distribution of chemical ingredients might also chemically represent characteristic components of herbal medicines for quality control.     

Établissement du profil chromatographique liquide non aqueux des métabolites phytochimiques apolaires des phytomédicaments

Chromatographic profiling of plant metabolites is therefore a good tool for quality control of such herbal medicinal products. Our objective was to propose a protocol for sample preparation and liquid chromatographic profiling of non-polar metabolites for quality assessment of African herbal medicinal products. The methodology is based on the chemometric assessment of liquid chromatographic profiles of non-polar metabolites issued from several batches of leaves of Combretum micranthum and Mitracarpus scaber. Metabolic profiling is carried out by non-aqueous liquid chromatography on porous carbon graphite, coupled with mass spectrometry, after extraction with dichloromethane and removal of chlorophyll. Our method using liquid chromatography, coupled to mass spectrometry can detect non-polar metabolites already identified in the two herbal drugs. Chemometric data analysis of chromatographic profiles using the PLS-discriminant analysis with or without orthogonal signal correction, allowed a distinction between the two herbal drugs.     

Enhanced chromatographic fingerprinting of herb materials by multi-wavelength selection and chemometrics

A strategy for multi-wavelength chromatographic fingerprinting of herbal materials, using high performance liquid chromatography with a UV–Vis diode array detector is presented. Valeriana officinalis was selected to show the proposed methodology since it is a widely used commercially available herbal drug, and because misfit with other valerian species is a current issue. The enhanced fingerprints were constructed by compiling into a single data vector the chromatograms from four wavelengths (226, 254, 280 and 326 nm), at which characteristic chemical constituents of studied herbs presented maximum absorbance. Chromatographic data pretreatment included baseline correction, normalization and correlation optimized warping. A simplex optimization was performed to retrieve the optimal values of the parameters used in the warping. General success rates of a classification above 90% were achieved by soft independent modeling of class analogy (SIMCA) and partial least squares discriminant analysis (PLS-DA). The sensitivity and specificity of constructed models were above 94%. Tests on laboratory-made mixtures showed that it is possible to detect adulterations or counterfeits with 5% foreign herbal material, even if it is from the Valerianaceae family. The results suggest that the proposed enhanced fingerprinting approach can be used to authenticate herb materials with complex chromatographic profiles.