An improved method for high temperature simulated distillation based upon ASTM D7169 is presented using the Zebron ZB-1XT SimDist column. This column utilizes a Glass Infusion™ Technology that results in more improved efficiency, resolution, and unmatched column-to-column reproducibility. This technology also allows simulated distillation methods, such as ASTM D6352 and D7169, to be extended from C100 to C120 while still meeting all the system suitability requirements.