College of Chemistry and Chemical Engineering, Research Center of Modernization of Chinese Medicines, Central South University, Changsha 410083, China.
J Chromatogr A. 2013 Apr 19;1286:175-82. doi: 10.1016/j.chroma.2013.02.063. Epub 2013 Feb 28.
Chromatography has been established as one of the most important analytical methods in the modern analytical laboratory. However, preprocessing of the chromatograms, especially peak alignment, is usually a time-consuming task prior to extracting useful information from the datasets because of the small unavoidable differences in the experimental conditions caused by minor changes and drift. Most of the alignment algorithms are performed on reduced datasets using only the detected peaks in the chromatograms, which means a loss of data and introduces the problem of extraction of peak data from the chromatographic profiles. These disadvantages can be overcome by using the full chromatographic information that is generated from hyphenated chromatographic instruments. A new alignment algorithm called CAMS (Chromatogram Alignment via Mass Spectra) is present here to correct the retention time shifts among chromatograms accurately and rapidly. In this report, peaks of each chromatogram were detected based on Continuous Wavelet Transform (CWT) with Haar wavelet and were aligned against the reference chromatogram via the correlation of mass spectra. The aligning procedure was accelerated by Fast Fourier Transform cross correlation (FFT cross correlation). This approach has been compared with several well-known alignment methods on real chromatographic datasets, which demonstrates that CAMS can preserve the shape of peaks and achieve a high quality alignment result. Furthermore, the CAMS method was implemented in the Matlab language and available as an open source package at http://www.github.com/matchcoder/CAMS.
色谱法已成为现代分析实验室中最重要的分析方法之一。然而，由于实验条件的微小变化和漂移会导致不可避免的差异，因此在从数据集中提取有用信息之前，对色谱图进行预处理，尤其是峰对齐，通常是一项耗时的任务。大多数对齐算法都是在使用仅在色谱图中检测到的峰的简化数据集上执行的，这意味着数据丢失，并引入了从色谱轮廓中提取峰数据的问题。这些缺点可以通过使用来自键合色谱仪器生成的完整色谱信息来克服。这里提出了一种新的对齐算法，称为 CAMS（通过质谱进行色谱对齐），可快速准确地校正色谱图之间的保留时间偏移。在本报告中，基于连续小波变换（CWT）和 Haar 小波检测每个色谱图的峰，并通过质谱相关性将其与参考色谱图对齐。通过快速傅里叶变换互相关（FFT 互相关）加速对齐过程。该方法已在真实色谱数据集上与几种知名对齐方法进行了比较，结果表明 CAMS 可以保持峰的形状并获得高质量的对齐结果。此外，CAMS 方法已在 Matlab 语言中实现，并可在 http://www.github.com/matchcoder/CAMS 上作为开源软件包获得。
