An ion transfer device that includes first and second ion guides, one or more RF voltage sources, and one or more DC voltage sources that produce first and second potential gradients in the first and second ion guides such that the potential gradients push the ions to move toward the outlet of each ion guide such that the one or more DC voltages produce a potential barrier, the potential barrier preventing the ions in the first ion guide from entering the second ion guide, the ions accumulate behind the potential barrier and form an ion packet, and the potential barrier is reduced after a predetermined time period to move the ion packet from the first ion guide to the second ion guide.