Characterization of peak capacity of microbore liquid chromatography columns using gradient kinetic plots

- Characterization of micro-LC columns in liquid chromatography.
- Peak capacity analysis for 0.3 mm i.d. columns.
- Influence of the extra-column volume contribution.
- Gradient kinetic plots for miniaturized LC columns.

The performance of micro-liquid chromatography columns with an inner diameter of 0.3 mm was investigated on a dedicated micro-LC system for gradient elution. Core-shell as well as fully porous particle packed columns were compared on the basis of peak capacity and gradient kinetic plot limits. The results for peak capacity showed the superior performance of columns packed with sub-2 μm fully porous particles compared to 3.0 μm fully porous and 2.7 μm core-shell particles within a range of different gradient time to column void time ratios. For ultra-fast chromatography a maximum peak capacity of 16 can be obtained using a 30 s gradient for the sub-2 μm fully porous particle packed column. A maximum peak capacity of 121 can be achieved using a 5 min gradient. In addition, the influence of an alternative detector cell on the basis of optical waveguide technology and contributing less to system variance was investigated showing an increased peak capacity for all applied gradient time/column void time ratios. Finally, the influence of pressure was evaluated indicating increased peak capacity for maximum performance whereas a limited benefit for ultra-fast chromatography with gradient times below 30 s was observed.