Temperature control in large-internal-diameter scaffolded monolithic columns operated at ultra-high pressures

• Highly robust organic-monolithic columns were prepared in a large titanium scaffold.
• Columns were prepared repeatedly and the metal scaffold could be recycled easily.
• Columns were sustainably used for separations at ultra-high pressures.
• Columns were efficiently used to reduce viscous heating under ultra-high pressures.

Scaffolding makes it feasible to create organic-polymer monoliths in large confinements, such as wide-bore columns. By creating the scaffold from a metal good heat conductivity inside the column is obtained, which renders the relatively large columns (comparable with 4.6 mm i.d.) suitable for application under ultra-high-pressure LC conditions. It was anticipated that the metal scaffold would allow accurate control of the temperature within the columns, but the temperature profiles within the columns could not be characterized using the previously available small-internal-diameter scaffolded columns. In the current study the internal diameter of the scaffolded columns was increased up to square conduits of 4 × 4 mm. Prior to the formation of the stationary phase the heating efficiency in the empty scaffolded conduits was addressed. The performance of stationary phases created in the large scaffolds was investigated using the kinetic performance approach and the results were compared to those of the previous studies. Finally, scaffolded columns were tested under ultra-high-pressure LC conditions, where good temperature control is essential.