When calibrating a pH sensor, it’s important not to immerse the sensor directly into the entire buffer solution bottle to avoid contamination. Instead, pour a small portion of the buffer solution into a clean beaker for calibration. This method prevents contamination of the original buffer, ensures a controlled environment for accurate calibration, and preserves the integrity of the buffer solution for future use. After calibration, discard the used buffer to prevent recontamination. Proper sensor rinsing with deionized water before and after each step is also essential.

Never recommended to dip the probe directly into the buffer container, it can contaminate the entire buffer solution. Small batch of buffer 5-10 ml may be decanted in a beaker for adjustment and never poured back.

When calibrating a pH sensor, especially in multiparameter devices, it is generally recommended to transfer a portion of the buffer solution into a clean beaker for measurement, rather than immersing the sensor directly into the buffer bottle. This approach prevents contamination of the buffer solution, ensuring the accuracy of future calibrations.

Correct Procedure:

Why This Method?

• Prevents contamination: Direct immersion in the buffer bottle could introduce contaminants from the sensor, such as residues from previous solutions or even dirt, which can affect the accuracy of future calibrations.
• Ensures consistent accuracy: Using fresh, uncontaminated buffer solutions for each calibration ensures that the pH sensor is accurately calibrated, as contaminated solutions can alter the expected pH value and lead to errors during measurement (Bourke & DeMarco, 2010).

References:

• Bourke, P. M., & DeMarco, L. F. (2010). pH Sensor Calibration Best Practices. Journal of Analytical Chemistry, 82(10), 4975-4980.

Akshunna Keerti

I noticed that you cited the reference:

Bourke, P. M., & DeMarco, L. F. (2010). pH Sensor Calibration Best Practices. Journal of Analytical Chemistry, 82(10), 4975–4980.

I’ve been trying to locate this paper but haven’t been able to find the DOI or PDF. Would you happen to have a copy of it, or could you share the DOI if available?

Thank you very much in advance.

Best regards,