OrgMassSpecR (version 0.5-3)

IsotopicDistribution: Isotopic Distribution of an Organic Molecule.

Description

Simulate the isotopic distribution of an organic molecule using the natural abundances of the isotopes.

Usage

IsotopicDistribution(formula = list(), charge = 1)

Arguments

formula

a list describing the charged elemental formula. The allowed elements are C, H, N, O, S, P, Br, Cl, F, Si.

charge

an integer specifying the number of positive or negative charges. A charge of zero is not allowed.

Value

A data frame with the following column names.

mz

the m/z value

intensity

the number of counts at each m/z value. The total is 10000.

percent

the intensity at each m/z value, expressed as a percent of the maximum intensity.

Details

The elemental formula should be that of the charged molecule; i.e, the charge argument does not change the elemental formula.

The algorithm used in this function is based on sample, and will give a slightly different result each time it is run.

This function is intended for simulating the isotopic distributions of small molecules (< approximately 3000 amu and <= 3 charges) as measured on low resolution mass spectrometers.

References

The relative atomic masses of the isotopes are from the NIST Physical Reference Data Website http://physics.nist.gov/PhysRefData/Compositions/.

See Also

IsotopicDistributionN, IsotopicDistributionHDX, sample

Examples

# NOT RUN {
x <- IsotopicDistribution(formula = list(C = 9, H = 4, Br = 5, Cl = 1, N = 2))
library(lattice)
xyplot(percent ~ mz, data = x,
  type = "h",
  xlab = "m/z",
  ylab = "intensity (%)",
  main = "Isotopic Distribution, C9H4Br5ClN2")
# }