Abstract: The present invention is directed to a method of isolating a target species (e.g., target nucleic acid species) from a mixture. In the methods of the present invention, the mixture is combined with solid phase carriers having a surface comprising multiple functional groups one of which reversibly and selectively binds the target species. In a particular embodiment, the mixture is combined with solid phase carriers having a first functional group which reversibly binds nucleic acids and a second functional group which selectively and reversibly binds the target nucleic acid species, thereby producing a first combination. The first combination is maintained under conditions appropriate for binding of the nucleic acids to the first functional group and binding of the target nucleic acid species to the second functional group. The solid phase carriers are separated from the first combination, and combined with an agent (e.g., buffer) that selectively removes (e.g.

Abstract: A method and device for introducing a sample, such as a nucleic acid sample, into an electrophoretic apparatus is provided in which the sample is introduced into the electrophoretic apparatus in the presence of a magnetic field. In a particular embodiment, the electrophoretic apparatus can include a nucleic acid sequencer. The sample can be introduced into the electrophoretic apparatus electrokinetically. The magnetic field attracts one or more magnetic microparticles that can be suspended or otherwise provided in the sample. The nucleic acid sample can be bound to one or more magnetic microparticles. In particular embodiments, the microparticles can be used to purify dye terminator sequencing reactions. The magnetic field can be formed by a rare earth magnet, such as neodymium, or by an electromagnet, or other suitable means. In particular embodiments, the sample can be injected into a nucleic acid sequencer by capillary electrophoresis and sequenced by the sequencer.