Graphene oxide (GO) is the high-biocompatible, good aqueous dispersible and low-cost material. Fluorescence quenching and adsorption capacity of GO, different affinity of single-stranded and double-stranded DNA molecules to GO are used to design GO-based fluorescent sensors to detect complementary single stranded DNA. In this work, in the framework of the development of graphene oxide-based test systems for the diagnosis of point mutations in DNA, we study fluorescence quenching efficiency of GO. The graphene oxides were prepared by the modified Hummers method at different synthesis conditions and were characterized. During the study, it was found that the reaction temperature is the most dominant parameter to control GO properties. GO suspension synthesized at 75 0 C of the reaction mixture showed the most high fluorescence quenching efficiency. Basing on XPS O1s, FT- IR spectra analysis, on data of the fluorescence emission spectra of dye-labeled DNA in the presence of various concentrations of GO it is found the effect of oxygen functional groups such as carboxyl, phenol, carbonyl, and epoxy on the efficiency of fluorescence quenching by GO. These results will be useful for in-depth studies of oligonucleotides and GO interaction and opens new opportunities for sensitive detection of biorecognition events.