MAIT (version 1.6.0)

peakAnnotation: Spectra constructor and peak annotator

Description

peakAnnotation function performs spectra building and peak annotation using the CAMERA package on a MAIT-class object, after applying the sampleProcessing function. The resultant xsAnnotate object is stored in a MAIT-class object.

Usage

peakAnnotation(MAIT.object = NULL,  corrWithSamp = 0.7,  perfwhm = 0.6,  sigma = 6,  adductTable = NULL,  printSpectraTable = TRUE,  corrBetSamp = 0.75, pval = 0.05,  calcIso = TRUE, calcCiS = TRUE,  calcCaS = TRUE, graphMethod = "hcs",  annotateAdducts = TRUE)

Arguments

MAIT.object

A MAIT-class object where function sampleProcessing has already been applied. The output of the function is going to be an update of the same MAIT-class object.

corrWithSamp

Correlation threshold value within samples

perfwhm

This parameter is used to group two peaks depending on their retention time. Two peaks are considered to be coeluted if their retention time falls in a range defined as Rt_med +/- FWHM * perfwhm. Where Rt_med is the retention time median and FWHM is the Full Width at Half Maximum. Defined this way, perfwhm is the percentage of the width of the FWHM (Full Width at Half Maximum)

sigma

Defining the coelution range as defined in the perfwhm variable, the FWHM is obtained by the expression FWHM=SD*sigma, where SD is calculated considering the peak as normally distributed.

adductTable

User-defined input table to annotate the peaks. If it is set to NULL, the default MAIT table for adducts in positive polarization is selected. If its value is "negAdducts", the default MAIT table for fragments in negative polarization is chosen. By default it is set to NULL.

printSpectraTable

If it is set to TRUE, a three-column table is build as a csv file, where the first column shows the peak mass, the second column its retention time and the third one shows its spectral ID number. This file is saved under the project directory, in the subfolder named Tables.

corrBetSamp

Correlation threshold value between samples

pval

See groupCorr function in the CAMERA package

calcIso

See groupCorr function in the CAMERA package

calcCiS

See groupCorr function in the CAMERA package

calcCaS

See groupCorr function in the CAMERA package

graphMethod

See groupCorr function in the CAMERA package

annotateAdducts

If it is set to TRUE, the function will perform an adduct annotation stage.

Value

A MAIT-class object containing the xsAnnotate-class in the rawData slot.

See Also

xsAnnotate,xsAnnotate-class

Examples

#Provided that the data files are saved accordingly 
#in subfolders under a folder named "data" (see vignette):
#MAIT<-sampleProcessing(dataDir = "data", project = "Results", snThres=2,rtStep=0.02)
#MAIT<-peakAnnotation(MAIT.object = MAIT,corrWithSamp = 0.7, corrBetSamp = 0.7,perfwhm = 0.6)