Having residues stuck to your electrode is the number one cause for inaccurate measurements. Here are some steps you can take for keeping your electrode clean.
Even if you are rinsing your electrode with water (deionized or distilled), you can still have residues coating the pH sensing glass and junction. DO NOT wipe your electrode with a cloth, paper towel, or even a kimwipe. Wiping the electrode can damage the pH sensing glass. Instead, use application specific cleaning solutions. In this article we will be talking primarily about four of the available cleaning solutions: general purpose, protein, inorganic, and oil and grease.
The following are Hanna's cleaning solutions (in 500 mL bottles).
- General Purpose pH Electrode Cleaning Solution (500 mL)
- Electrode Cleaning Solution for Oil and Fats (500 mL)
- Cleaning Solution for Proteins (500 mL)
- Cleaning Solution for Wine Deposits (500 mL)
- Grease and Fats Acid Cleaning Solution (500 mL)
- GroLine General Purpose Cleaning Solution (500 mL)
- Cleaning Solution for Salt Deposits (500 mL)
- Cleaning & Disinfection Solution for Dairy Products (500 mL)
- Cleaning Solution for Milk Deposits (500 mL)
- Cleaning Solution for Cheese Deposits (500 mL)
- Cleaning Solution for Skin Grease and Sebum (500 mL)
- Electrode Cleaning Solution for Inorganic Substances (500 mL)
- Cleaning Solution for Ink Stains (500 mL)
- Cleaning Solution for Wine Stains (500 mL)
- Cleaning Solution for Yogurt Deposits (500 mL)
- Cleaning Solution for Oil and Fats in FDA Bottle (500 mL)
- Cleaning Solution for Proteins in FDA Bottle (500 mL)
- Grease and Fats Alkaline Cleaning Solution (500 mL)
- Cleaning & Disinfection Solution for Algae, Fungi and Bacteria (500 mL)
- Cleaning Solution for Humus Deposits (500 mL)
- Cleaning Solution for Soil Deposits (500 mL)
- Cleaning & Disinfection Solution for Blood Products (500 mL)
- General Purpose Cleaning Solution in FDA Bottle (500 mL)
General Cleaning Procedure
For general cleaning, soak your pH electrode in the HI7061L General Purpose Cleaning Solution for at least 15 minutes. Then rinse the electrode with water before allowing it to rehydrate in HI70300L storage solution for at least one hour (overnight for best results).
Protein Coating
Soak your electrode in the HI7073L Protein Cleaning Solution for at least 15 minutes to enzymatically dissolve protein deposits. Then rinse the electrode with water before allowing it to rehydrate in HI70300L storage solution for at least one hour (overnight for best results).
Inorganic Soak
Soak the electrode in HI7074L Inorganic Cleaning Solution for at least 15 minutes. This cleaner is very effective at removing precipitates caused by a reaction with the silver in the filling solution that may form in a ceramic junction. Then rinse the electrode with water before allowing it to rehydrate in HI70300L storage solution for at least one hour (overnight for best results).
Oil and Grease
Oil and grease residues are tricky - they love to stick to glass. Their removal requires the correct chemicals to dissolve the coating, but they need to be mild enough to leave the electrode unaffected. Use the HI7077L Oil and Fat Cleaning Solution and soak for at least 15 minutes. Then rinse the electrode with water before allowing it to rehydrate in HI70300L storage solution for at least one hour (overnight for best results).