Blank measurement based time-alignment in LC-MS

Here are presenting the blank based time-alignment (BBTA) as a strong analytical approach for treatment of non-linear shift in time occurring in HPLC-MS data. Need of such tool in recent large dataset produced by analytical chemistry and so-called omics studies is evident. Proposed approach is based on measurement and comparison of blank and analyzed sample evident features. In the first step of BBTA procedure, the number of compounds is reduced by max-to-mean ratio thresholding, which extensively reduce the computational time. Simple thresholding is followed by selection of time markers defined from blank inflex points which are then used for the transformation function, polynomial of second degree, in the example. BBTA approach was compared on real HPLC-MS measurement with Correlation Optimized Warping (COW) method. It was proved to have distinctively shorter computational time as well as lower level of mathematical presumptions. The BBTA is computationally much easier, quicker (more then 1000×) and accurate in comparison with warping. Moreover, markers selection works efficiently without any peak detection. It is sufficient to analyze only baseline contribution in the analyte measurement with sparse knowledge of blank behavior. Finally, BBTA does not required usage of extra internal standards and due to its simplicity it has a potential to be widespread tool in HPLC-MS data treatment. It is described in details, mathematically and experimentally justify approach for time alignment of LC-MS spectra using blank measurement data as (inherent) internal standards (BBTA). BBTA utilizes solvent contaminants and other important events (inflex points) detectable both in blank run and the compared experiment for alignment of multiple 2D chromatograms. Addition of internal standards may increase number of data points available for calculation but is not necessary for general laboratory practice. Obvious advantage of BBTA is its readiness and essentially low expenditure level of its application. All mathematical descriptions are derived immediately from the system based description of the measurement data sets with respect to the common used definitions.