Acquisition strategy for top-down analysis with reduced background and peak overlapping

Abstract

Intensity measurements made by electron multiplier and image-charge detectors are proportional to charge state. These intensities are used to separate detected ions into different data sets and create mass spectra from the different data sets. Ion measurements are separated by charge state using (i) a single electron multiplier detector, (ii) a single image-charge detector, or (iii) multiple electron multiplier ADC detectors. Using (i), the intensity of a peak calculated from each measured pulse is compared to predetermined intensity ranges and each peak is stored in a corresponding data set. Using (ii), each measured transient time-domain signal is converted to frequency-domain peaks, the intensity of each frequency-domain peak is compared to predetermined intensity ranges, and each peak is stored in a corresponding data set. Using (iii), each detector is adapted to measure a predetermined intensity range and store calculated peaks from the measured pulses in corresponding data sets.