Patent ID: 8664406

Claim:
A fluorescence probe compound of formula I: wherein R 1 , R 2 , R 3 and R 4 are each independently selected from the group consisting of H, C 1 - 18 alkyl, C 1 - 18 alkyl substituted phenyl, C 1 - 18 alkyl substituted naphthyl, halogen, OR 9 , N(R 9 ) 2 , CN, (CH 2 CH 2 O) n H, (CH 2 ) m COOM, and (CH 2 ) m SO 3 M; R 5 , R 6 , R 7 and R 8 are each independently selected from the group consisting of H, C 1 - 18 alkyl, C 1 - 18 alkyl substituted phenyl, C 1 - 18 alkyl substituted naphthyl, halogen, hydroxyl, mercapto group, cyano group, nitro group, heterocyclic group, halogenated alkyl, alkyl amino group, acylamino group, OR 9 , N(R 9 ) 2 , (CH 2 CH 2 O) n H, (CH 2 ) m COOM and, (CH 2 ) m SO 3 M; R 9 is selected from the group consisting of H, C 1 - 18 alkyl, C 1 - 18 alkyl substituted phenyl, C 1 - 18 alkyl substituted naphthyl, halogen, CN, (CH 2 CH 2 O) n H, (CH 2 ) m COOM, and (CH 2 ) m SO 3 M; n and m are integers independently selected from 0 to 18; M is selected from the group consisting of H, K, Na, Li, NH 4 , NH 3 R 10 , NH 2 (R 10 ) 2 , NH (R 10 ) 3 , and N(R 10 ) 4 ; and R 10 is selected from the group consisting of H, C 1 - 6 alkyl, and CH 2 CH 2 OH.