Resprep QR-12 and QR-24 Quick-Replace vacuum manifolds enable analysts using solid phase extraction (SPE) cartridges to simultaneously prepare up to 12 or 24 samples. These manifolds are designed to eliminate the risk of contamination when consecutive samples are extracted in a manifold port. They are equipped with integral flow control valves, and each valve has an inexpensive, disposable PTFE liner/solvent guide running through its length. This guide acts as a liner so that all surfaces that come in contact with a sample can be discarded and replaced following each extraction. A luer hub attached to the PTFE liner fits snugly into a matching slot on the flow control valve stem. As the SPE cartridge is rotated on its axis, the valve pinches or releases the liner, stopping or starting the flow.