Synchronous coefficient of drag alteration (SCODA) is a biotechnology method for purifying, separating and/or concentrating bio-molecules. SCODA has the ability to separate molecules whose mobility (or drag) can be altered in sync with a driving field. This technique has been primarily used for concentrating and purifying DNA, where DNA mobility changes with an applied electrophoretic field. Electrophoretic SCODA has also been demonstrated with RNA and proteins.