Estimate the m/z resolution of a spectrum
estimateMzResolution estimates the m/z resolution of a profile-mode
Spectrum (or of all spectra in an MSnExp or OnDiskMSnExp object.
The m/z resolution is defined as the most frequent difference between a
spectrum's m/z values.
## S4 method for signature 'MSnExp' estimateMzResolution(object, ...) ## S4 method for signature 'Spectrum' estimateMzResolution(object, ...)
object |
either a |
... |
currently not used. |
numeric(1) with the m/z resolution. If called on a MSnExp or
OnDiskMSnExp a list of m/z resolutions are returned (one for
each spectrum).
This assumes the data to be in profile mode and does not return meaningful results for centroided data.
The estimated m/z resolution depends on the number of ions detected in a spectrum, as some instrument don't measure (or report) signal if below a certain threshold.
Johannes Rainer
## Load a profile mode example file
library(MSnbase)
library(msdata)
f <- proteomics(full.names = TRUE,
pattern = "TMT_Erwinia_1uLSike_Top10HCD_isol2_45stepped_60min_01.mzML.gz")
od <- readMSData(f, mode = "onDisk")
## Estimate the m/z resolution on the 3rd spectrum.
estimateMzResolution(od[[3]])
## Estimate the m/z resolution for each spectrum
mzr <- estimateMzResolution(od)
## plot the distribution of estimated m/z resolutions. The bimodal
## distribution represents the m/z resolution of the MS1 (first peak) and
## MS2 spectra (second peak).
plot(density(unlist(mzr)))Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.