The Use and Care of Electrodes for pH Meters

When ordering or using a pH meter, you need a pH electrode and at least two pH buffers, one at pH 7 and the other at either pH 4 or 10. Proper care of electrodes is necessary for a ph meter to function well.

Oakton® pH Electrode (Epoxy Body, Sealed, Single-junction, General Purpose, 3-ft (0.9-m) Cable, BNC Connector)

Oakton® pH Electrode (Epoxy Body, Sealed, Single-junction, General Purpose, 3-ft (0.9-m) Cable, BNC Connector)

Electrode deterioration can occur as a result of depletion, contamination, and clogging. The reference electrode’s ions (suspended in liquid, gel, or a polymer) are very slowly depleted with use. Electrolyte depletion occurs with all pH electrodes. Here are some tips on how to handle and maintain your electrodes for optimal use:

Handling—Electrodes should be rinsed between samples with distilled or deionized water and gently blotted (NEVER WIPED) dry with a lab wipe.

Refillable Electrodes—When adding filling solution, fill up to, but not past, the refill hole. When measuring, leave the refill hole open for proper flow through the reference junction.

Calibration—with NIST-traceable pH buffers will align the two half cells of the electrode and pH meter. It is important to use fresh buffer. Use pH 7 (for offset) and at least one other buffer (for slope) to frame the pH range of your samples.

Storage—Always keep your pH electrode moist by storing it in 4 M KCL solution. If 4 M KCl is not available, use a pH 4 or 7 buffer solution. (Note: DO NOT store electrode in distilled or deionized water.) After storage, if you notice white KCl crystals forming outside your electrode, simply rinse the electrode and blot dry with a lab wipe before use.

Protective Bottle—Electrodes are shipped with a protective bottle over the glass bulb. Remove the bottle before using your electrode. For long-term storage just fill the bottle with enough 4 M KCl solution to cover the glass bulb and replenish as needed to keep the bulb moist.

View the video on pH Electrode Maintenance


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