Calculate Average Molecular Weight from Chemical Formulas

Calculates the average molecular weight of one or more chemical formulas, based on the natural isotopic distribution of elements. The calculation uses the enviPat package to retrieve isotopic masses and abundances, and computes the weighted mean of the isotopic distribution.

Usage

calc_average_molweight(formula)

Arguments

formula

A character vector of one or more chemical formulas to process.

Value

A numeric vector of average molecular weights, one for each formula.

Details

This function calculates the average molecular weight (not monoisotopic mass), which reflects the average of the isotopic distribution found in nature.

Isotopes can be specified explicitly in the formula. Atomic mass numbers for isotopes must be enclosed in square brackets (e.g., [13]C for carbon-13). Deuterium must be written as D instead of [3]H.

The function uses the enviPat package to validate and parse chemical formulas, calculate isotopic patterns, and determine the average molecular weight based on weighted means of isotopic abundances.

References

Loos, M., Gerber, C., Corona, F., Hollender, J., & Singer, H. (2015). Accelerated Isotope Fine Structure Calculation Using Pruned Transition Trees. Analytical Chemistry, 87(11), 5738–5744. doi:10.1021/acs.analchem.5b00941

Examples

calc_average_molweight(c("C6H12O6", "[13]C6H12O6", "C8H10N4O2", "D2O"))
#> [1] 180.15613 186.11184 194.19090  20.02761