Patent ID: 7642344

Claim:
A compound of the formula: T ms —L—X wherein a) T ms is an organic group detectable by mass spectrometry, and has the formula: wherein G is (CH 2 ) 1-6 wherein a hydrogen on one and only one of the CH 2 groups of each G is replaced with —(CH 2 ) c -Amide-T 4 ; T 2 and T 4 are organic of and are moieties the formula C 1-25 N 0-9 O 0-9 S 0-3 P 0-3 H α F β I δ wherein the sum of α, β and δ is sufficient to satisfy the otherwise unsatisfied valencies of the C, N, O, S and P atoms; R 1 is hydrogen or C 1-10 alkyl; c is an integer ranging from 0 to 4; and n is an integer ranging from 1 to 50 such that when n is greater than 1, G, c, Amide, R 1 and T 4 are independently selected; b) L is an organic group which allows a T ms -containing moiety to be cleaved from the remainder of the compound, and has the formula L 1 —L 2 —L 3 , wherein L 2 is a molecular fragment that absorbs actinic radiation to promote the cleavage of T ms from X, L 1 and L 3 are independently a direct bond or an organic moiety, where L 1 separates L 2 from T ms and L 3 separates L 2 from X, and neither L 1 nor L 3 undergoes bond cleavage when L 2 absorbs the actinic radiation, L 2 has the formula: with one carbon atom at positions a, b, c, d or e being substituted with —L 3 — X and optionally one or more of positions b, c, d or e being substituted with alkyl, alkoxy, fluoride, chloride, hydroxyl, carboxylate or amide; and R 1 is hydrogen or hydrocarbyl; and c) X is a nucleic acid fragment attached to L at other than the 3′ end of the nucleic acid fragment; with the provisos that the compound is not bonded to a solid support through X nor has a mass of less than 250 daltons.