GC047 Inlet Temperature

The inlet must be hot enough to produce a fast vaporization of the sample without loss of efficiency from the injection technique. At the same time, very high inlet temperatures should be avoided, because thermal decomposition or chemical rearrangement can be produced. A general rule for flash vaporization is to have an inlet temperature 50ºC above the boiling point of the sample. Tests of the inlet temperature can be performed. If increasing the temperature produce better peak shapes or improves efficiency, the temperature was too low. If drastic changes are observed in retention times, peak areas or peak shapes, the temperature was too high, probably leading to thermal decomposition or rearrangements. On the other hand, in on-column injections, the inlet temperature can be lower.

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