Circular Geometry in Molecular Stream Separation to Facilitate Non-Orthogonal Field-to-Flow Orientation

Molecular stream separation (MSS) is a promising complement for continuous-flow synthesis. MSS is driven by forces exerted on molecules by a field applied at an angle to the stream-carrying flow. MSS has only been performed with a 90 field-to-flow angle because of a rectangular geometry of canonic MSS; the second-order rotational symmetry of a rectangle prevents any other angle. Here, we propose a non-canonic circular geometry for MSS, which allows changing the field-to-flow angle. We conducted in silico and experimental studies of circular geometry for continuous-flow electrophoresis (CFE, an MSS method). Counterintuitively, circular CFE was found to support better flow and electric-field uniformity than rectangular CFE. We proved that the nonorthogonal field-to-flow orientation can result in a higher stream resolution than the orthogonal one. We foresee that circular CFE will serve as a new testbed for the investigation and creation of new CFE modalities.