TITLE: Care and Cleaning of pH Probes
AUTHORS: francesca.galdi

[DESCRIPTION]
This is the protocol we use to clean the probes used with the OGI Bio pH Module.  

[BEFORE_START]
Ensure sterile conditions are maintained all through the protocol.

[GUIDELINES]
The probes should be cleaned immediately after an experiment to prevent contamination.
The protocol steps should be carried out in quick succession to prevent the probe tip from drying out.
pH probes should always be stored wet, with the tip soaked in Sentek electrode storage solution.

[STEPS]
SECTION: Prior to Running an Experiment
1. Prior to removing the storage sleeve, visually inspect the probe for trapped air bubbles within the electrolyte solution.  If bubbles are present, shake probe in a downward motion to remove them.
SECTION: Prior to Running an Experiment
2. Unwrap the parafilm and remove the storage sleeve from the probe.
SECTION: Prior to Running an Experiment
3. Rinse the storage sleeve with ultrapure water and shake to remove any residues of water.
SECTION: Prior to Running an Experiment
4. Rinse the probe by spraying ultrapure water on the thicker portion and allowing it to run down the lower shaft.
SECTION: Prior to Running an Experiment
6. Gently dab dry the probe with a paper towel.
SECTION: Prior to Running an Experiment
5. Repeat Step 4 with 70% ethanol.
SECTION: Prior to Running an Experiment
7. Insert the pH probe through the flask bung.
SECTION: Prior to Running an Experiment
8. Spray the lower protruding glass portion of the probe with 70% ethanol.
SECTION: Prior to Running an Experiment
9. Fill the storage sleeve with 70% ethanol.
SECTION: Prior to Running an Experiment
10. Pinch the top of the sleeve to temporarily deform it, such that air cannot be trapped inside the sleeve when it is slid onto the electrode's tip.
SECTION: Prior to Running an Experiment
11. Slide the deformed sleeve onto the electrode's tip and remove after 1 minute.
SECTION: Prior to Running an Experiment
12. Rinse the sleeve with ultrapure water and set aside to dry.
SECTION: Prior to Running an Experiment
13. Rinse the lower portion of the pH probe with ultrapure water.  It is now ready for an experiment.
SECTION: After an Experiment
14. Remove the probe from the bung.
SECTION: After an Experiment
15. Spray ultrapure water on the thicker portion and allowing it to run down the lower shaft.  Perform this and other washes over a designated waste bottle.
SECTION: After an Experiment
16. Repeat Step 15 with 70% ethanol.
SECTION: After an Experiment
17. Rinse the storage sleeve with ultrapure water and shake to remove excess liquid.
SECTION: After an Experiment
18. Repeat Steps 9 through 11.
SECTION: After an Experiment
19. Repeat Steps 15 and 17.
SECTION: After an Experiment
21. Pipette 100 μL of Sentek electrode storage solution into the sleeve.
SECTION: After an Experiment
22. Pinching the top of the sleeve as in Step 10, slide the sleeve over the end of the pH probe.
SECTION: After an Experiment
20. Gently dab the probe dry with a paper towel.
SECTION: After an Experiment
23. Dab away any excess fluid with a paper towel.
SECTION: After an Experiment
24. Wrap the sleeve with parafilm such that the film secures the end of the sleeve to the glass of the probe.  Store upright to prevent the formation of bubbles within the electrolyte solution.