Gas chromatographic retention in uncoated fused silica capillaries

Understanding of retention in uncoated fused-silica capillaries is of interest due to increased attention on precolumn backflushing in capillary GC. Uncoated capillaries offer several advantages as precolumns compared to coated precolumns. In order to examine the possibility of predicting elution temperatures of alkanes from uncoated capillaries a priori, several sizes of deactivated but uncoated fused-silica capillaries were evaluated under various operating conditions. Retention was found to depend on dimensionless ramp rate (degrees C/t(M)), sample loading (capacity), flow mode, and column dimensions (probably related to surface area).