Analysis of Four-Way Two-Dimensional Liquid Chromatography-Diode Array Data: Application to Metabolomics

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• 作者：Sarah E. G. Porter ; Dwight R. Stoll ; Sarah C. Rutan ; Peter W. Carr ; Jerry D. Cohen
• 刊名：Analytical Chemistry
• 出版年：2006
• 出版时间：August 1, 2006
• 年：2006
• 卷：78
• 期：15
• 页码：5559 - 5569
• 全文大小：417K
• 年卷期：v.78,no.15(August 1, 2006)
• ISSN：1520-6882

文摘

Two-dimensional liquid chromatography (2D-LC) is rapidly gaining popularity for the analysis of very complexmixtures, including proteomic and metabolomic samples.It provides an effective strategy for separating suchsamples, because the resolving power of 2D-LC is farsuperior to that of traditional single-dimension separations. The present work focuses on the development ofdata analysis methods for the extremely large data sets,on the order of 10 million data points, generated by 2D-LC with diode-array detection (DAD). Specifically, we haveapplied and adapted chemometric methods to the analysisof maize seedling digests, focusing on compounds relatedto the biosynthetic pathways of indole-3-acetic acid, theprimary growth regulator in plants. The chemometric techniques of window target testing factor analysis (WTTFA),along with parallel factor analysis - alternating leastsquares (PARAFAC-ALS) were used to analyze 2D-LC-DAD chromatograms of a sample composed of 26 indolicstandards, 2 extracts of mutant orange pericarp maizeseedlings, 2 extracts of wild-type maize seedlings, and ablank sample. The indolic compounds studied belongedto six spectrally unique groups, and WTTFA was able tospecifically identify the presence or absence of any of the26 indolic standards in the mutant and wild-type samples.A PARAFAC-ALS algorithm and an ALS algorithm withflexible constraints were successfully applied to resolvethe spectrally rank deficient data and to demonstrate thequantitative potential of multivariate curve resolutionmethods. Using this procedure, 95 total peaks wereresolved in the data set analyzed. Of those 95 peaks, 45were found in both the mutant and wild-type maizesamples, 16 peaks were unique to the mutant maizesamples, 13 peaks were unique to the wild-type maizesamples, and 15 peaks were unique to the standardchromatograms. Of the 26 standards included in the dataset, several indole acetic acid conjugates were identifiedand quantified in the maize samples at levels of approximately 0.3-2 ges/entities/mgr.gif">g/g plant material.