. . "A detectable molecule of the formula A3 --(--X--R1 --E--Detb)m where A3 is an oligo- or polynucleotide having at least one modifiable reactive group consisting of amino, hydroxy, cis OH, halide, aryl, imidazoyl, carbonyl, carboxyl, thiol or a residue comprising an activated carbon; --X-- is selected from the group consisting of ##STR54## --R1 -- is ##STR55## a C1 -C10 branched or unbranched alkyl" . .