The present invention is based on the observation that radio frequency (RF) electric fields in multi-pole lenses with small rod diameters in the range of 1 mm enables strongly concentrating ions suspended in a gas at pressures much higher than previously used for ion manipulation, including atmospheric pressure. Other lens configurations are described, including one based on the funnels of U.S. Pat. No. 6,107,628, and another on the coiled wire system of Hutchins et al. (1999). The finding provides a method to increase the concentration of ions transmitted to mass spectrometers and other analyzers, both from volatile or involatile species in solution, hence increasing their analytical sensitivity. It also enables improved charging efficiencies of neutral volatile species existing in the gas phase.