Preparative Chromatography - The Maximum Sample Volume > Page 7




The equation indicates that the maximum acceptable sample volume can be calculated from the retention volume of the solute concerned and the efficiency of the column. It is also shows, that the maximum sample volume will increase with the retention volume of the solute, and decrease inversely as the square root of the efficiency.

From the point of view of preparative separations the practical implication is that the sample volume can be increased by adjusting the mobile phase so that the solute pair is eluted later. Apparently, this procedure would also increase the separation time, but this may not always be a disadvantage as for simple separation this may allow more than one sample to be separated in the column at one time. The maximum sample volume is important when the separation ratio of a solute pair is relatively small, and adequate resolution is only just obtainable from the column. If, however, the stationary phase provides good selectivity between the solute pair of interest, and provides a length of base line between the two peaks, then column overload might be justified.