A separatory funnel with a PTFE (Polytetrafluoroethylene) stopcock is a specialized piece of laboratory glassware used primarily for liquid-liquid extractions. It allows scientists to separate a mixture into two immiscible solvent phases of different densities (typically an aqueous phase and an organic phase)
The abbreviation P.T.F.E specifically indicates that the control valve (stopcock) at the bottom is made of Teflon, a highly chemical-resistant polymer.
Core Anatomy & DesignBody Shape: Typically features a Squibb (pear-shaped) or conical design. This wide top tapers down gradually into a narrow base, which helps clearly isolate and define the boundary layer (interface) between the two liquids.
Material: Built from premium borosilicate glass (such as Pyrex or Boro 3.3). This provides high resistance to thermal shock, structural durability, and inertness against harsh solvents
Top Neck: Outfitted with a ground glass joint socket that hosts an interchangeable plastic (polyethylene) or glass stopper. This ensures a secure, leak-proof seal during rigorous shaking and inversion.

Drip Stem: A narrow tube at the very bottom beneath the stopcock, often cut at an angle to ensure clean, precise dispensing of the liquid layer without dripping.