I'd like to increase the source temperature of Scion GC-MS to 280 Celsius. The company's recommendation is 200 Celsius. However, when analyzing the target compound, the source temperature is too low. Why is it 200 Celsius? And I wonder what the characteristics of Scion's equipment are.
When an ion source temperature is high, reactions that may not occur in lower temperatures such as dehydration of tertiary or allylic alcohols can happen. This could lead misidentication of compounds observed, when NIST or other libraries are used for search. As Noel mentioned, keeping the transfer line at a high temperature (250 or above) is a good idea, instead of keeping the ion source at the high temperature.
I do not know that instrument, but going beyong manufactorers specs is usually not a good idea. with EU sources, I would expect rapid buring of filaments and rapid oxidation of surfaces with so high temperatures.
What is the elution temperature of the target compound?
This is related to boiling point of the compound and mainly column oven - inlet temperature should be well operated to make the compound volatile sufficiently to be analyzed at GC system. Other than these, as suggested above, transfer line should be at the temperature at which the compounds must remained as volatile and not to be condensed during the column effluent introduced to EI chamber. Between 250 to 300 is generally works for most of the compounds.
For EI ionization source, higher temperature is not needed and the set temperature is not related to boiling point of your target molecule...
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