FitPeakByIsotopicRatio {CorrectOverloadedPeaks}R Documentation

Extrapolate a flat top peak using isotopic ratios.

Description

FitPeakByIsotopicRatio will take a data frame containing peak data for retention time ('RT'), as well as mass and intensity information of M0, M+1 and M+2 and extrapolate all points above a certain threshold for Int_M0 based on further parameters using an IsotopicRatio approach.

Usage

FitPeakByIsotopicRatio(cor_df = NULL, idx = NULL, silent = TRUE)

Arguments

cor_df

A data frame containing information about the overloaded area; columns=(Scan, RT, mz0, int0, mz1, int1, mz2, int2, modified).

idx

If not NULL, 'idx' is expected to specify points to correct explicitly (as a numeric-vector within 1:length(x)).

silent

For testing purposes some QC-plot will be generated if silent=FALSE.

Details

Isotopic ratios within ion traces of molecules can be considered stable. If this ratio is changed because one molecule, let's say the M+0, is exceeding the detector range while another (say M+1) is still quantifiable, we therefore may attempt to modify M+0 by multiplying the values of M+1 with a constant (the stable ratio). This constant is determined ideally from the values within the peak front. As this function is mainly used internally (CorrectOverloadedPeaks), it is not very flexible with respect to the input format. Please prepare a dataframe according to the parameter specifications or process a file using CorrectOverloadedPeaks with testing=TRUE, which will generate a list structure of such dataframes.

Value

An annotated plot of the mass spectrum and detailed information within the console. Main result will be returned invisible.


[Package CorrectOverloadedPeaks version 1.2.17 Index]