The GC6890system with HSS8650 HeadSpace Autosampler as a sample preparation method was evaluated in order to perform an easier and quicker analysis of dissolved gases in transformer oil. HeadSpace sample preparation method allows the automation of the ASTM method with the possibility of doing sequences of 32 samples in less than 20 minutes for each analysis. References 1. ASTM Method D 3612-01, "Standard Test Method for analysis of Gases Dissolved in electrical Insulating Oil by Gas Chromatography"