What should you do to avoid faulty pH meter calibrations?

• A. Use fresh buffer solution for each calibration.
• B. Calibrate at a consistent temperature with old buffers.
• C. Submerge the sensor for an extended period before calibration.
• D. Replace the meter probe after every calibration.

Answer: (A)

Using fresh buffer solutions for calibration ensures the pH values you reference are accurate and reflect the electrode’s response at the calibration temperature. Buffers age and can drift due to CO2 absorption, evaporation, or contamination, making old solutions unreliable as standards. Fresh buffers minimize these shifts, giving you a reliable reference point to set the electrode’s slope and offset. Temperature matters in pH measurements, but even at a steady calibration temperature, old buffers can lead to incorrect calibration values. Submerging the sensor longer than needed before calibration doesn’t reliably improve accuracy and can introduce surface contamination, while replacing the probe after every calibration is unnecessary and wasteful.