When comparing silica gel there are chromatographic parameters that are important to consider. These parameters are retention factor (k), selectivity (α), and efficiency (N). These factors combined are responsible for the overall peak resolution (Rs). While these can very on a case by case basis with specific compounds, the separation of acetophenone and 4-methoxyacetophenone is well documented.
Retention Factor (k) – Related to the interaction of the silica and the compound, a larger k value typically indicates the compound spent longer interacting with the silica.
Selectivity (α) – The ability of the chromatographic system to separate or chemically distinguish different compounds in a sample. The higher the value the more selective the system is. If α is equal to 1, the compounds co-elute.
Efficiency (N) – The theoretical plate number or efficiency is a measure of the peak dispersion on the column, the higher the N, the more efficient the column is.
Resolution (Rs) – The resolution relates all three of the above parameters (retention factor, selectivity, and efficiency) to describe the separation of two identified peaks.
The following chromatograms were obtained using a 40-gram chromatography column packed with the specific media of choice. The flow rate was maintained at 30mL/min for the equilibration step and the chromatography separation. The sample tested was 100mg/mL of acetophenone and 100mg/mL of 4’-methoxyacetophenone for a total concentration of 200mg/mL for the test sample. For the 1% loading testing, 2mL of the test sample or 400mg is loaded onto the column, for 5% loading 10mL or 2g of sample is loaded.