Lab on Diffusion and Membranes

Equipment List

• Conductivity Probe: For measuring conductivity.
• Rinse Beaker and Bottle: Filled with deionized (DI) water for cleaning the probe.
• 600ml Beaker and Stir Station: For containing and stirring solutions.
• Glass Dish: For soaking strips of membrane tubing.
• Scissors and Ruler: For cutting the membrane tubing to the correct length.
• Dry Uncut Tubing: Material for creating artificial cells.
• Tubing Clamps: Two clamps for sealing the ends of the membrane tubing.
• 10ml Graduated Cylinder and Dropper: For measuring and transferring liquids.

Procedure

Preparation

1. Locate DI Water Tap: Use only DI water.
2. Cut Membrane Tubing: Measure and cut two strips of P32 membrane tubing.
3. Soak Tubing: Place the tubing in a dish filled with DI water for about 5 minutes.

Setting Up the Beaker

1. Fill Beaker with DI Water: Place on the stir station.
2. Insert Stir Bar: Drop a magnetic stir bar into the beaker.
3. Adjust Stir Station: Set to its lowest setting where the stir bar just begins to spin.

Preparing Test Solution

1. Retrieve Test Solution: Use the 10ml graduated cylinder and dropper to obtain test solutions from the back lab bench.
2. Keep Track of Solutions: Ensure solutions are not mixed.

Assembling the Artificial Cell

1. Remove and Open Tubing: After softening, clamp one end and open the other.
2. Fill Tubing: Use the dropper to transfer the test liquid into the tubing.
3. Clamp Tubing: Seal the top with a clamp.
4. Rinse Assembled Cell: Hold over rinse beaker and clean with DI bottle.

Conductivity Testing

1. Set Up Logger Pro Software: Prepare for data recording.
2. Place Conductivity Probe: Insert into the beaker without disturbing the stir.
3. Submerge Tubing Cell: Carefully place in beaker and start data recording immediately.

Post-Trial Procedure

1. End Trial: Remove the beaker from the stir station.
2. Clean Probe: Rinse with DI water and store in the rinse beaker.
3. Empty and Clean Cell: Unfasten clamps and pour contents back into the beaker.
4. Remove Stir Bar: Use fingers or retriever.
5. Store Equipment: Keep track of clamps and stir bar.
6. Clean Beaker: Rinse with DI water and pour out at the sink.