Described is an active check valve that uses electro-magnetic actuation for operation. The valve includes a plunger assembly having a magnet in a sealed internal volume. The plunger assembly further includes a plunger tip that extends from either a plunger assembly housing or a sealing member. Although the plunger assembly is disposed in the solvent flow, the magnet is not exposed to the solvent. When the valve is actuated, the plunger tip moves the sealing member to open or close the valve. Optionally, an arming force may be applied to the sealing member in advance of opening or closing to reduce the subsequent additional force necessary to move the sealing member during opening or closing, thereby improving the accuracy of the solvent composition in liquid chromatography system applications.