Since in nominal-mass GC data m/z values are rounded to whole numbers, in some cases an m/z value may occur multiple times - in that case the mean of the intensities is kept (and the retention times are averaged). removeDoubleMasses takes a list of spectra in the form of a three-column matrix, (mz, I, rt), summing the intensities and averaging the retention times for multiple identical masses. Not meant to be called directly by the user.
A list of spectra, each one consisting of a three-column matrix (mz, I, rt).
The function returns a list of spectra, where all "double" peaks have been averaged.