elemental composition from exact mass

dear R-listers,

does anyone of you know whether there is any R package that features a
alogarithm to calculate the sum formula from a given exact mass (as
used in mass spectrometry)?

thanks a lot,
lukas

Lukas Kohl
Department of Chemical Ecology and Ecosystem Research
http://www.ecosystem-research.netecosystem-research.net
University of Vienna
Althanstra?e 14, 1090 Vienna, Austr