Skip to main content
Chemistry LibreTexts

7. Pressure Assembly

See the Custom Built CE Schematic for a diagram.

This section describes the assembly of the pressure injection system (See Custom-built CE Schematic) used to introduce sample plugs into the bare-fused silica capillary. It is important to note that copper and Teflon tubing should be installed and used according to the manufacturer’s specifications and recommendations.

  1. A tank of compressed helium should be strapped safely to the cabinet. A pressure regulator should already be connected to the gas tank.

    Pressure Regulator.

  2. Copper tubing should connect the pressure regulator to the pressure valve using a quick connector.
  3. The pressure valve is then connected to a 1/8” union T.
  4. The union T is then connected to the 3-way valve by copper tubing. The 3-way valve controls the flow of pressure to the sample vial (“ON/OFF” switch).

    Three-Way Valve.

  5. The 3-way valve is then connected to the solenoid valve by copper tubing.

    Bottom: Pressure Assembly

  6. The black and red wires from the Solenoid valve connect to an electronic timer.

    Pressure Assembly and Timer

  7. The solenoid valve is then connected back to the union T by copper tubing.
  8. The 3-way valve also connects to the plastic pressure tubing. The pressure tubing should go through a hole in the plexi-glass box and pierce the septa and be placed right above the sample. The plastic tubing SHOULD NOT be submerged in the sample.