R/spectraCreate.R

In adductomicsR: Processing of adductomic mass spectral datasets

#' Deconvolute both MS2 and MS1 levels scans adductomics
#'
#' @param MS2file character vector of mzXML file locations
#' @param TICfilter numeric minimimum total ion current of an MS/MS scan. Any
#' MS/MS scan below this value will be filtered out (default=0).
#' @param DNF dynamic noise filter minimum signal to noise threshold
#' (default = 2), calculated as the ratio between the linear model predicted
#' intensity value and the actual intensity.
#' @param minInt numeric minimum intensity value
#' @param minPeaks minimum number of signal peaks following dynamic
#' noise filtration (default = 5).
#' @examples spectraCreate(MS2file = paste0(system.file("extdata", package =
#' "adductData"),'/ORB35017.mzXML'), TICfilter = 10000, DNF= 2, minInt =
#' 100, minPeaks = 5)
#' @usage spectraCreate(MS2file = NULL, TICfilter = 10000, DNF = 2, minInt =
#' 100, minPeaks = 5)
#' @return list of MS2 spectra
#'@export
spectraCreate <- function(MS2file = NULL,
                          TICfilter = 10000,
                          DNF = 2,
                          minInt = 100,
                          minPeaks = 5) {
    # MS2 file name
    MS2fileName <- basename(MS2file)
    message(paste0("Reading ", MS2fileName, "...\n"))
    
    # read MS2 file
    MS2file <- mzR::openMSfile(MS2file)
    message("...DONE")
    
    message("extracting metaData from MS2 file...\n")
    
    # extract info from MS/MS file
    fileInfoDf <- mzR::header(MS2file)
    message("...DONE\n")
    
    # remove all MS/MS scans where the TIC is less than
    #the minimum TIC threshold set
    # by the user
    message(paste0("Of a total of ",
                   length(which(
                       fileInfoDf$msLevel == 2
                   )), " MS2 spectra...\n"))
    
    # index ms2 scan and above TIC filter
    fileInfoDf$MS2TICfilt <- (fileInfoDf$msLevel == 2 &
                                  fileInfoDf$totIonCurrent >
                                  TICfilter) * 1
    MS2TICfilt.indx <- which(fileInfoDf$MS2TICfilt == 1)
    message(paste0(
        length(MS2TICfilt.indx),
        " MS2 spectra were above the TIC filter of ",
        TICfilter
    ))
    
    if (length(MS2TICfilt.indx) == 0) {
        # cond if no scan above the TIC filter
        warning(
            paste0(
                "No MS2 levels scans above TIC filter of ",
                TICfilter,
                " in ",
                MS2fileName,
                ",  reduce the TIC filter parameter or check that
                the file has been converted
                to the mzXML format correctly."
            ),
            immediate. = TRUE
            )
        
        message("...moving to next MS2 file")
        
    } else {
        # applying loess variable baseline noise removal
        message("applying savitsky-golay baseline subtraction...\n")
        
        
        savGolRemSpectra <- lapply(MS2TICfilt.indx, function(scan) {
            specDfTmp <- mzR::peaks(MS2file, scan)
            savGolTmp <- pracma::savgol(specDfTmp[, 2], 51)
            specDfTmp[, 2] <- specDfTmp[, 2] - savGolTmp
            specDfTmp <-
                specDfTmp[specDfTmp[, 2] > 0, , drop = FALSE]
        })
        
        if (DNF > 0) {
            message("Applying dynamic noise filter...\n")
            
        }
        NoiseFiltSpectra <-
            lapply(savGolRemSpectra, function(spec) {
                dynamicNoiseFilter(spec, DNF, minPeaks, minInt)
            })
        # id all above min/ noise
        aboveMinPeaksIndx <- vapply(NoiseFiltSpectra,
                                    function(spec)
                                        spec$aboveMinPeaks, FUN.VALUE =
                                        logical(1))
        
        if (all(aboveMinPeaksIndx == FALSE)) {
            warning(
                " No composite spectra were found
                above the DNF filter of ",
                DNF,
                " or any peaks above the minimum
                intensity (minInt) ",
                minInt,
                " or minimum peaks setting of ",
                minPeaks,
                " in ",
                MS2fileName,
                " consider reducing one of more of these
                parameter settings and/or",
                " check that the file has been converted
                to the mzXML format correctly.",
                immediate. = TRUE
            )
            
            message("...moving to next MS2 file")
            
        } else {
            # unlist and rbind metaData and add to file.info dataframe
            NoiseFiltSpectra <-
                unlist(NoiseFiltSpectra, recursive =
                           FALSE)
            metaData <- do.call("rbind",
                                NoiseFiltSpectra[which(
                                    names(NoiseFiltSpectra) == "metaData")])
            metaData <- data.frame(metaData,
                                   aboveMinPeaks = aboveMinPeaksIndx * 1)
            fileInfoDf[, colnames(metaData)] <- 0
            fileInfoDf[MS2TICfilt.indx, colnames(metaData)] <-
                metaData
            message("...done")
            # spectra
            specNames <- fileInfoDf$acquisitionNum[fileInfoDf$aboveMinPeaks
                                                   == 1]
            MS2spectra <- NoiseFiltSpectra[which(
                names(NoiseFiltSpectra) == "Above.noise")][aboveMinPeaksIndx]
            names(MS2spectra) <- specNames
            return(list(metaData = fileInfoDf, MS2spectra =
                            MS2spectra))
            close(MS2file)
        }  # cond if no spectra are above noise filter
    }  # cond if no scan above the TIC filter
}  # end func