The invention relates to acquisition techniques for time-of-flight 
mass spectra with 
ionization of the 
analyte substances by matrix assisted 
laser desorption. Generally speaking, these acquisition techniques involve adding together a large number of individual time-of-flight spectra, each with restricted dynamic measuring range, to form a sum spectrum. The invention provides a method that improves, in particular, the reproducibility, the concentration accuracy and therefore the ability to quantify the 
mass spectra. Particular embodiments also increase the 
dynamic range of measurement. For this purpose, multiple series of 
mass spectra are acquired, whereby the 
energy density in the 
laser spot is increased in discrete steps. As a result, many 
ion signals saturate the 
detector and can therefore no longer be evaluated. However, it is possible to employ a technique in which the 
ion beam is increasingly defocused, or, secondly, to replace parts of the spectrum that are subject to saturation by intensity extrapolations from mass spectra acquired with lower 
energy density. In the first case, hundreds or thousands of individual mass spectra must be added together in order to increase the dynamic measuring range. In the second case, the finally acquired 
mass spectrum, with its replacements, forms a 
mass spectrum with a high dynamic measuring range, improved reproducibility and better concentration accuracy. The gradient of the increasing intensities of the 
ion signals, as a function of the 
energy density, supplies additional information about the 
proton affinity of the 
analyte ions. The concentration accuracy is enhanced because the increase in the number of 
proton donors in the 
ionization plasma leads to an increase in the 
ionization of those 
analyte substances that have a lower 
proton affinity.