Enhanced Q1 Mass Segregation in Scanning SWATH

A method of mass spectrometry, comprising:

• during each time cycle of a plurality of t time cycles, stepping a precursor ion transmission window of fixed length l mass-to-charge ratio (m/z) in k overlapping steps that are Δm m/z apart entirely across a mass range r m/z (l<r) from a starting ml m/z of the mass range and n−1 more times starting at n−1 different offsets from ml between ml and ml+Δm, producing n scans of the mass range and a total of k×n steps of the transmission window for each time cycle, and, for each step of the transmission window, fragmenting the transmitted precursor ions and mass analyzing the resulting product ions, producing k×n product ion spectra that are a function of precursor ion m/z for each time cycle, using a mass spectrometer;
• selecting at least one product ion from the k×n×t product ion spectra produced over the t time cycles using a processor;
• and
• for at least one time cycle of the t time cycles, reconstructing an intensity of the at least one product ion as a function of precursor ion m/z with a resolving power greater than Δm by combining intensities of the at least one product ion as a function of precursor ion m/z measured with a resolving power of Δm during each of the n scans for the at least one time cycle using a linear reconstruction algorithm using the processor.

A computer program product, comprising a non-transitory tangible computer-readable storage medium whose contents include a program with instructions being executed on a processor for a mass spectrometry method, comprising:

• providing a system, wherein the system comprises one or more distinct software modules, and wherein the distinct software modules comprise a control module and an analysis module;
• instructing a mass spectrometer to, during each time cycle of a plurality of t time cycles, step a precursor ion transmission window of fixed length l mass-to-charge ratio (m/z) in k overlapping steps that are Δm m/z apart entirely across a mass range r m/z (l<r) from a starting ml m/z of the mass range and n−1 more times starting at n−1 different offsets from ml between ml and ml+Δm, producing n scans of the mass range and a total of k×n steps of the transmission window for each time cycle, and, for each step of the transmission window, fragment the transmitted precursor ions and mass analyze the resulting product ions, producing k×n product ion spectra that are a function of precursor ion m/z for each time cycle, using the control module;
• selecting at least one product ion from the k×n×t product ion spectra produced over the t time cycles using the analysis module;
• and
• for at least one time cycle of the t time cycles, reconstructing an intensity of the at least one product ion as a function of precursor ion m/z with a resolving power greater than Δm by combining intensities of the at least one product ion as a function of precursor ion m/z measured with a resolving power of Δm during each of the n scans for the at least one time cycle using a linear reconstruction algorithm using the analysis module.