Patent ID: 8227621
Filing Date: 2012-07-24
Classification: C09B,G01N

Abstract:
1. An essentially non-fluorescent compound of formula Ib: wherein: R  group to which they are bonded form a 5- to 7-membered ring, said ring being optionally substituted with 1 to 4 substituents selected from the group consisting of halogen, cyano, sulfonate, (C R or alternatively the substituents R 3 and R 4 are replaced with the group wherein B is (C 1 -C 6 )alkyl; or B and R 9a together with the carbon atoms to which they are attached join to form a 5- or 6-membered ring optionally having 1 or 2 heteroatoms and optionally having up to 3double bonds; R R R a is an integer from 0-3; b is an integer from 0-2; and A is selected from the group consisting of hydrogen, halogen, cyano, optionally substituted (C wherein R wherein said compound contains at least one linking group; wherein said compound has at least one —NR wherein R wherein said compound is essentially non-fluorescent and is charge neutral.