Since sample is metered by reversal movement of the syringe pump, the injected sample volume can conveniently be optimized. This feature was confirmed in a work where also comparison of SIC with HPLC was carried out (Šatínský 2003).
A Chromolith® Flash RP-18e, 25mm × 4.6mm column (Merck, Germany) was used for separations with a mobile phase of acetonitrile:water (40:70 (v/v)) + 0.05% triethylamine, pH 2.5. A gradient flow rate was applied for separation of methylparaben (MP), propylparaben (PB), and sodium dichlofenac (SD) with a butylparaben (BP) internal standard Comparison of the resulting chromatograms demonstrate that SIC yields separations that are similar to the performance of HPLC.
This finding is likely to apply to isocratic separation of a small number (~5) of components. For a larger number of components, the physical and mechanical limitations of SIC hardware (finite syringe stroke volume, low back pressure tolerance, limited gradient capability) are restricting separation efficiency.