Importance of Thermal Parameters in Solid-Phase Micro-Extraction (SPME) Analysis

SPME is a powerful trace analysis technique which involves several thermal processes: fiber cleaning, conditioning, surface analyte adsorption, and desorption in the analytical device. Fiber conditioning is a main operation, since it results in a severe modification of the fiber surface, enhancing its adsorptive properties. The influence and orders of magnitude of the thermal parameters required for desorption are evaluated and discussed. The cooling down due to adsorbate desorption is completely negligible in comparison with the heat transfer capabilities of the system. Thus, the limiting factor is not heat transfer, but desorption activation energy.