An extraction cell cap assembly allows for toolless disassembly. The assembly includes a cap body having a threaded base releasably engaged with a cell vessel, a support member extending axially upward from the base, and a bore axially extending through the support member. The assembly also includes a locking cap having a plunger slidably received within the bore, a recess disposed within the plunger, and a locking portion that releasably engages the support member. Rotation of the locking cap in a first direction engages the locking portion with the support member, and rotation in an opposite direction disengages the locking portion. A filter is received in the recess and a seal member received in the bore, wherein the seal member forms a fluid-tight seal between the cell vessel and the assembly when the locking portion and the support member are engaged and the assembly is secured to the cell vessel.