The present invention provides a method for producing a mass-coded
combinatorial library comprising a set of compounds having the general
formula X(Y).sub.n, where X is a scaffold, each Y is, independently, a
peripheral moiety, and n is an integer greater than 1. The method
comprises selecting a peripheral moiety precursor subset from a peripheral
moiety precursor set. The subset includes a sufficient number of
peripheral moiety precursors that at least about 50 distinct combinations
of n peripheral moieties derived from the peripheral moiety precursors in
the subset exist. The subset of peripheral moiety precursors is selected
so that at least about 90% of all possible combinations of n peripheral
moieties derived from the subset have a molecular mass sum which is
distinct from the molecular mass sums of all of the other combinations of
n peripheral moieties. The method further comprises contacting the
peripheral moiety precursor subset with a scaffold precursor which has n
reactive groups. Methods of use of the mass-coded combinatorial library
produced by this method for identifying a ligand to a particular
biomolecule are also disclosed.
