What's the difference between temperature compensation and temperature correction? (pH verses Conductivity temperature adjustments)

Document ID

Document ID TE6094

Published Date

Published Date 04/04/2019
Question
What's the difference between temperature compensation and temperature correction? (pH verses Conductivity temperature adjustments)
Summary
Temperature compensation vs correction.
Answer
Temperature compensation is a term most common to pH measurement. This refers to using the measured temperature in the calculation of the final result instead of using a reference temperature of 25 °C. This way the result is the pH of the solution at that temperature, instead of pH of a solution at 25 °C with the measured mV.

Temperature correction is a term most common to conductivity. This refers to the measured conductivity being converted by a factor based on the measured temperature to display an estimated conductivity if the sample were to be at reference temperature (usually 25 °C) instead of the measured temperature. This can be linear (a factor of x% per °C from the reference temperature) or non-linear where the percentage factor varies depending on the difference between the measured temperature and reference temperature. Non-linear temperature correction curves are exclusively based on a standard, and can be different depending on the standard that the curve is based on. With conductivity temperature correction, there can be a different correction for the calibration than there is for measurement. Calibrations are commonly non-linear corrections, whereas the measurement corrections can be either. This is because the relationship between conductivity and temperature is more clearly defined on a standard, but can vary on samples based on sample matrix. The IntelliCAL™ CDC401 as an example will use a non-linear temperature correction curve specific to the selected standard if one of the preset standards is used for calibration. If a custom standard is used it will use and adjustable linear correction factor defaulting to 2%/°C. For measurement it uses the Non-linear NaCL standard based temperature correction curve by default, but can be changed to either non-linear natural water curve based on 442-30 natural water standards or linear with an adjustable factor.

 

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