Quote:
Originally Posted by Naja002
... Is there anything around the house that's good for cleaning a probe? Wouldn't happen to have a link handy, would ya? I'd like to try to clean this one before I toss it......  |
Quote:
Originally Posted by Left C
I believe that you can soak it in a warm 4 pH buffer solution to clean it, but let me check around first.
I'll check around this afternoon. I don't have time right now. I'm going to have lunch with this 80 years young lady today. She's a blast to talk too.
I remember seeing some articles a while back and I'll check out my biotechnology books too.
|
This comes from the book:
Basic Laboratory Methods for Biotechnology: Textbook and Laboratory Reference by Seidman and Moore. Pages 357 and 358
Cleaning the Junction of a Reference Electrode
These methods are suitable for combination electrodes or individual reference electrodes. The first methods are least drastic and should be tried first. Continue to the next step only if the previous one has failed.
-
For gel-filled and calomel references, soak the electrode tip in warm water (about 60°C or 140°F) for 5 – 10 minutes. Be careful not to heat the water much above 60°C.
-
Dissolve crystals from the end of the electrode by soaking in a solution of 10% KCl and 90% distilled water for between 20 minutes and 3 hours. Warm the solution to about 50°C or 122°F. Immerse the electrode about 2” into the solution.
-
Use a commercially available junction cleaner.
-
Remove any proteins that coat the outside of electrodes or penetrate into the junction. Recommendations for removing protein deposits include rinsing in enzyme detergent like
Tergazyme (from Alconox) or using pepsin/HCl cleaners like
Oakton Electrode Cleaner.
Cleaning the Measuring Electrode Bulb
Use a soft tooth brush, Q-tip or tissue to clean the bulb. Gently wipe or pat the bulb; do not rub.
-
Remove dirt with warm soapy water. A mild dish washing detergent without hand lotion can be used.
-
Remove protein contaminants by washing in warm water with an enzyme detergent like Tergazyme or Oakton’s Electrode Cleaner followed by rinsing in water.
-
Remove inorganic deposits by washing with EDTA, ammonia or 0.1 N HCl. Rinse the bulb with water and soak it in dilute KCl.
-
Remove grease and oil with methanol or acetone. Rinse the bulb with water and soak it in dilute KCl.
-
To remove fingerprints, wipe the bulb gently with a 50/50 mixture of acetone and isopropyl alcohol. Soak the electrode in a commercial soaking solution or pH 4 buffer for 1 hour.
Rejuvenating a Measuring Electrode Bulb
Note that solutions used for soaking and conditioning a pH measuring electrode are usually slightly acidic. This is because H+ ions from the soaking solutions replace contaminates in the glass of the bulb.
Some manufactures recommend the following steps when the linearity of the system is poor or the system response is sluggish. The first methods are least drastic and should be tried first. Continue to the next step only if the previous one has failed.
-
Soak the bulb in pH 4 calibration buffer overnight.
-
Soak the bulb in 1 M HCl for 30 minutes.
-
Immerse the bulb in 0.1 M HCl for about 15 seconds, rinse with water, then immerse in 0.1 M KOH (or 0.1 M NaOH) for 15 seconds. Repeat several times and rinse. Soak the electrode in pH 4 buffer overnight.
Here are some additional sources of information:
http://www.phadjustment.com/pH_Probe_Service.htm
http://home.comcast.net/~mzapx1/FAQ/pHProbes.pdf
http://home.comcast.net/~mzapx1/FAQ/pHProbes.pdf