Get the selected isotopologues at certain MS data
Arguments
- formula
the molecular formula. 'C6H11O6' as default
- charge
the charge of that molecular. 1 in EI mode as default
- width
the width of the peak width on mass spectrum. 0.3 as default for low resolution mass spectrum.
- cutoff
numeric, minimum relative abundance (fraction of base peak) to consider, default 0.05 (5%).