Patent ID: 7662993

Claim:
An isolated labeled compound of the formulae wherein Q is selected from the group consisting of —S(═O)—, and —S(═O) 2 —, Z is an aryl group selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure wherein R 1 , R 2 , R 3 , R 4 and R 5 are each independently selected from the group consisting of hydrogen, a C 1 -C 4 lower alkyl, a halogen, and an amino group selected from the group consisting of NH 2 , NHR and NRR′ where R and R′ are each independently selected from the group consisting of a C 1 -C 4 lower alkyl, an aryl group, and an alkoxy group, and X is selected from the group consisting of hydrogen, a C 1 -C 4 lower alkyl group, and a fully-deuterated C 1 -C 4 lower alkyl group.