mass2mz: Calculate mass-to-charge ratio

In rformassspectrometry/MetaboCoreUtils: Core Utils for Metabolomics Data

Calculate mass-to-charge ratio

Description

mass2mz calculates the m/z value from a neutral mass and an adduct definition.

Custom adduct definitions can be passed to the adduct parameter in form of a data.frame. This data.frame is expected to have columns "mass_add" and "mass_multi" defining the additive and multiplicative part of the calculation. See adducts() for examples.

Usage

mass2mz(x, adduct = "[M+H]+")

Arguments

x	numeric neutral mass for which the adduct m/z shall be calculated.
adduct	either a character specifying the name(s) of the adduct(s) for which the m/z should be calculated or a data.frame with the adduct definition. See adductNames() for supported adduct names and the description for more information on the expected format if a data.frame is provided.

Value

numeric matrix with same number of rows than elements in x and number of columns being equal to the length of adduct (adduct names are used as column names). Each column thus represents the m/z of x for each defined adduct.

Author(s)

Michael Witting, Johannes Rainer

See Also

mz2mass() for the reverse calculation, adductNames() for supported adduct definitions.

Examples

exact_mass <- c(100, 200, 250)
adduct <- "[M+H]+"

## Calculate m/z of [M+H]+ adduct from neutral mass
mass2mz(exact_mass, adduct)

exact_mass <- 100
adduct <- "[M+Na]+"

## Calculate m/z of [M+Na]+ adduct from neutral mass
mass2mz(exact_mass, adduct)

## Calculate m/z of multiple adducts from neutral mass
mass2mz(exact_mass, adduct = adductNames())

## Provide a custom adduct definition.
adds <- data.frame(mass_add = c(1, 2, 3), mass_multi = c(1, 2, 0.5))
rownames(adds) <- c("a", "b", "c")
mass2mz(c(100, 200), adds)

rformassspectrometry/MetaboCoreUtils documentation built on Oct. 2, 2024, 5:13 a.m.