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RaMS (version 1.4.3)

grabMzmlMS2: Extract the MS2 data from an mzML nodeset

Description

Extract the MS2 data from an mzML nodeset

Usage

grabMzmlMS2(xml_data, rtrange, file_metadata, incl_polarity)

Value

A `data.table` with columns for retention time (rt), precursor m/z (premz), fragment m/z (fragmz), collision energy (voltage), and intensity (int).

Arguments

xml_data

An `xml2` nodeset, usually created by applying `read_xml` to an mzML file.

rtrange

A vector of length 2 containing an upper and lower bound on retention times of interest. Providing a range here can speed up load times (although not enormously, as the entire file must still be read) and reduce the final object's size.

file_metadata

Information about the file used to decode the binary arrays containing m/z and intensity information.

incl_polarity

Boolean determining whether the polarity of the scan should be returned as a column in the table (positive mode = 1, negative mode = -1)