▎ 摘　　要

Fluorescence quenching of four dyes [acridine orange (AO), rhodamine B (Rd B), rhodamine 110 (Rd 110), and rhodamine 640 (Rd 640)] by colloidal graphene oxide (GO) in phosphate buffer (pH 6.0) was studied. Dynamic and static quenching were analyzed using the Stern-Volmer equation. Static quenching by graphene oxide was observed for AO, Rd 640, and Rd B whereas mixed dynamic and static quenching was characteristic of Rd 110. The Stern-Volmer constant of dynamic quenching was 10 times less than that of static quenching. The measured association constants of the dyes with GO fell in the order 2540 (AO) > 495 (Rd 640) > 260 (Rd 110) > 144 L/g (Rd B). The value of the pi-pi-stacking interaction was strongly influenced by the phthalic fragment oriented perpendicular to the xanthene in the rhodamine dyes and the four alkyl groups of Rd B as a result of their torsional vibrations and rotational motions.