pH Electrode Tips for Successful Analysis
Upon original receipt, inspect for damage in shipping or any visible defects. Initiate first use procedure per manufacturer’s instructions. Perform a calibration, check electrode slope (if required), and continue use. Fresh pH calibration buffers are recommended for each calibration.
For back-up electrodes, store per manufacturer’s recommendations and check performance monthly. Most electrode sensing ends should be kept hydrated between samples and during storage in solution recommended by the manufacturer.
Rinse with water and blot with Kimwipes® or other soft tissue between calibration buffers and samples. Avoid wiping the sensing end of electrodes. For refillable style electrodes, ensure the fill aperture remains exposed to air during calibration and sampling. Electrodes, especially low-maintenance, non-refillable styles should be placed in an upright position to keep internal reference solution in contact with the sensing end.
For analysis of hot or cold product, place an automatic temperature compensator (ATC) simultaneously with the pH electrode in the sample. Many 3-in-1 electrodes with built-in ATC are available. A higher degree of accuracy is achieved if calibration buffers and samples are virtually the same temperature.
Samples for pH analysis should be the best representation of product to ensure the highest accuracy possible. Product should be blended or mixed to avoid areas or pockets of high/low salt or dilution. Product needs to surround the electrode sensing end to create a ‘bridge’ between the electrode and sample.
At the very minimum, pH electrodes should be cleaned once daily to keep them working properly.
Soak the electrode tip in a solution of fat solvent or diluted Dawn detergent for up to 10 minutes. Rinse and blot electrode and swirl tip in electrode cleaner following manufacturer instructions.
Rinse and blot again, and place in storage solution for at least one hour. Electrode should be ready for use.
Electrode cleaner, protein cleaner, and other electrode cleaning agents are available. Follow manufacturer instructions for use of these cleaners. Electrodes have a fixed usable life, and may require replacement if electrode does not perform adequately following cleaning procedures.
A more detailed pH Measurement and Troubleshooting Guide from Nelson-Jameson is available upon request.