Amicon Microcon and Centri concentrifugal devices are efficient laboratory tools for removing small molecules from solutions of proteins ornucleic acids. Often, the molecule tobe removed is one of a number ofcommonly used protein solubilizing agents, or detergents. The chemical nature of most deter-gents allows for micelle formation above a critical concentration limit(Critical Micelle Concentration,CMC). Micelle formation results inaggregation of the detergent andleads to gross changes in molecular structure. This affects the amount ofthe detergent that can be removed from a solution by Microcon andCentricon devices with specific molecular weight cut-off (MWCO)membranes.