Abstract: The invention provides gel filtration columns for the purification of an analyte (e.g., a biological macromolecule, such as a peptide, protein or nucleic acid) from a sample solution, as well as methods for making and using such columns. The columns typically include a bed of gel filtration media positioned above a bottom frit or between a bottom and top frit. In some embodiments, the columns employ modified pipette tips as column bodies. In some embodiments, the invention provides methods and devices for desalting and/or buffer exchange of a sample.