pH-meter at 4°C, how to calibrate it? - pH of Tris depends on temperature (Sep/09/2005 )
I have a problem - I want to know exactly, what pH have my Tris-HCl buffer solutions at 4°C, as I will utilise them for the proteins, and I want the pH be away from the isoelectric point of protein.
I know, that with the lowering of the tempereture to every 10°, the pH of Tris solutions go up to 0.3.
It is no difficulties for me to transfer the pH -metr in the coldroom, but the question is the calibration of the pH metr. Should the standard solutions for the calibration be also chilled? Have they the same pH (7 or 4) chilled, as they have in the room temperature?
The standard buffers used to calibrate the pH meter (pH 7 and 4) are also only pH7 or 4 at 20 degrees. So you can not simply move everything to the coldroom.
It is an interesting question, but I have never heard of commercial available buffers that can be used to calibrate your pH meter at 4 degrees.
For this kind of things we have a pH meter with a temperature probe. So we can calibrate at room temperature a measure pH at 4ºC without problems.
Other wise I found a table of errors of pH depending on temperature here.
Hope this maybe of some help