Optimization of the high-performance liquid chromatographic separation of fullerenes using 1-methylnaphthalene as the mobile phase on a tetraphenylporphyrin-silica stationary phase

Abstract

The separation of C 60 and C 70 was studied on four different stationary phases. The performance of three commercial products, Buckyclutchers, PYE and PBB and of a new phase, immobilized tetraphenylporphyrin on silica, were investigated. The influence of the surface chemistry on this separation is discussed. On all four phases, good resolution is obtained with pure toluene as the mobile phase. With some of them, this result is obtained with stronger eluents, mixtures of toluene and 1-methylnaphthalene. This allows the injection of much more concentrated and larger samples than on conventional systems and gives considerably improved production rates of purified compounds. The optimization of the temperature, the flow velocity, and the mobile phase composition for the separation of C 60 and C 70 on the tetraphenylporphyrin bonded phase is discussed. The overloading of this stationary phase was studied empirically in mixtures of toluene and 1-methylnaphthalene. The advantage and properties of this latter solvent are illustrated. Fractions of C 60 with 98.5% purity and C 70 with a purity better than 99%% were prepared with near total recovery yield from 5 mg samples.