This article reports on a route to synthesizing fluorescent labeled graft copolymers, on the one hand; and on a concept of tracer-compatibilizer for facile build-up of emulsification curves of polymer blends, on the other hand. For these purposes, blends composed of polystyrene (PS) and polyamide 6 (PA6) are chosen. The synthesis of the corresponding tracer-compatibilizer consists of three steps: (1) copolymerization of styrene with 3-isopropenyl-a,a'-dimethybenzyl isocyanate (TMI); (2) conversion of a fraction of the isocyanate moieties of the resulting copolymer into anthracene ones upon reacting with 9-(methylamino-methyl)anthracene (MAMA); and (3) polymerization of e-caprolactam (CL) from the remaining isocyanate moieties. The resulting fluorescent labeled graft copolymer, denoted as PS-g-PA6-Ant, is used to build up emulsification curves of PS/PA6 blends in a twin screw extruder (TSE), showing great usefulness of the concept of tracer-compatibilizer. POLYM. ENG. SCI. 2012. (C) 2011 Society of Plastics Engineers