Matlab data preprocessing

The present authors have implemented a software tool called oplAnalyzer in MATLAB for MALDI-MS data preprocessing. To detect peaks in a mass spectrum, a search is made for locations of maximal value within a local m/z window, the size of which is 11 discrete sampUng points. This method is similar to another peak detection method [35]. For alignment, peak detection is applied to the mean spectra, analogous to the method of Karpievitch and others [34]. Subsequently, the peaks in an individual spectrum are aligned to this set of common peaks. For each common peak, its value in an individual spectrum is that of the closest detected peak in that spectrum if the distance between the common peak and the closest peak (in the m/z axis) is less than Vs Da. (A better choice is based on the actual mass accuracy of the measurement) If there is no such peak, then the m/z of the... 

All data preprocessing was carried out by software written in-house in 64-bit MATLAB (The Mathworks, Natick, MA, USA) for the automatic analysis of an entire data set at one time. The sequence of data processing steps for each of the 409,600 spectra data set is summarized later. A more detailed discussion of all steps involved can be found in the literature [16]. 

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