The solvent-exchange process from toluene was used for preparing aqueous dispersions of C60 and C70 without preconcentration with final concentrations of 180 ± 2 and 62 ± 1 µM, respectively, which exceeds the previously reported maximum concentrations for C60 more than 6-fold; for C70 such an aqueous dispersion is prepared for the first time. The residual quantity of the organic solvent and low-molecular compounds determined by headspace GC-MS was not more than 1 ppb. The procedure for the determination of fullerenes in aqueous dispersions is developed using a total organic carbon analyzer and absorption spectra; LOD, 50 nM, LOQ, 200 nM by TOC. Spectrophotometric determination of fullerenes in their aqueous dispersions was optimized: for C60 at 268 nm: LOD, 0.1 µM, LOQ, 0.3 µM, for C70 at 218 nm: LOD, 0.1 µM, LOQ, 0.3 µM. RSD mixture quantification by Vierordt’s method in the range of 2 – 20 µM does not exceed 0.14 for C60 and 0.09 C70. RSD for toluene fullerene mixtures by Vierordt’s method in the range of 2 – 20 µM does not exceed 0.10 for C60 and 0.06 for C70.