Why is the repeatability of melting point measurement with melting point meter poor? What caused it? Please know the friend to analyze it?

The principle of melting point instrument is very simple, that is, put the sample in a capillary tube, then raise the temperature, and see the sample melt under the microscope, and the reading temperature is the melting point ~

The value obtained can only be an approximate range ~

Because you don't know its actual melting point when you set it, you can only set a slightly higher temperature, and then the instrument will gradually heat up under the control of programmed heating, and there is no feedback mechanism, so it doesn't matter whether your sample melts or not; If the temperature you set is much higher than your melting point, all the samples may become liquid at once, and I don't know where the temperature soared at first sight ~

Secondly, the melting process is not very beautiful. The number, compactness or looseness of your samples have a great influence on your observation, so the repeatability may not be very good ~

I hope I can help you ~