Temperature influences sample and buffer pH and electrode characteristics. Temperature dependency for all common buffers is known and is usually stated on the buffer bottle or on a separate form sent with the buffers from reputable manufacturers. Temperature has a minimal effect on inorganic acid buffers. It has a significant effect, however, on alkaline buffers and on some organic buffers. Please check the buffer tables in Appendix B. Compensation can be made for the influence of temperature on the slope of the electrodes, though no compensation can be made for pH shifts caused by altered reference potentials or a change of the pH in the inner solution in the glass bulb. In addition, almost nothing is known about the influence of temperature on a sample's pH. The temperature of the sample should be recorded along with the pH of the sample.
In summary, electrodes, buffers, and samples should all be at the same temperature. Though some compensation is possible, it is not possible to calculate the pH of a sample measured at one temperature back to the sample pH at another temperature, for example, a reference temperature. A temperature difference, however, of 2 - 5¡Æ C will be acceptable in most cases.
When pH vs. mV at a number of different temperatures is plotted for most electrodes, note that the lines intersect at almost the same point.