Dual functionality of Obelisc N column allows to retain and provide efficient peaks of strong carboxylic acids such as TFA. Simple UV quantitation and identification method became possible due to the unique properties of this stationary phase. In case of an RP separation poor retention and peak symmetry was obtained at a very low concentration of ACN. Sulfuric acid was used to suppress ionization of TFA to increase the hydrophobicity. In case of a typical HILIC column the phosphoric acid was used to increase ionization to make TFA more polar to enhance polar retention. The types of columns that do not have the mixed mode nature of Obelisc N can't provide significant retention and efficiency.