Improved peak analysis of signals based on counting systems: Illustrated for proton-transfer-reaction time-of-flight mass spectrometry

Statistical analysis of measured signals from counting systems is a common method to increase the accuracy and precision of peak position and peak area. The most common approach to analyze data gained from counting systems is to fit the data peak by peak using an appropriate probability density function (PDF) like a Gaussian function. Since a counting system creates histograms, the counted data do not represent data points of the anticipated PDF. Therefore, one should not fit any PDF directly to the histogram data. Here we present a solution to this problem by fitting distributions instead of densities. A simple formula allows to correct for Poisson statistics and dead-time effects. The improved peak analysis method is applied to mass spectra obtained from a recently developed proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF) enhancing the mass accuracy and peak quantification. (C) 2010 Elsevier B.V. All rights reserved.