Topics - Retention Distance

Retention Distance Retention distance is a term, not often used today but was important when the output from the detector was presented on a potentiometric recorder chart as opposed to being processed on a computer. The retention distance is the distance on the chart displaying the chromatogram from the point of injection to the maximum of the peak of interest. This distance can be used for calculating the column efficiency. By subtracting the dead volume distance (the distance on the chart from the injection point to the peak maximum of a completely unretained solute) from the retention distance, the ‘corrected’ retention distance can be obtained. Multiplying the corrected retention distance by the chart speed and the flow rate (corrected for the compressibility of the mobile phase if the mobile phase is a gas) will give the ‘corrected’ retention volume which can be used to help identify the solute and to provide thermodynamic data. Today the computer can automatically calculate the column efficiency and the corrected retention volume of a solute and present the results either on the computer monitor or the printer