The Concentration Sensitivity of a Chromatographic System

The concentration sensitivity of a chromatographic system is defined as that concentration of solute that will provide a peak height equivalent to twice the noise level. The concentration sensitivity of a chromatographic system can be derived directly from the system mass sensitivity. If the minimum detectable mass is dissolved in the maximum permissible sample volume (that sample volume that will limit the increase in peak variance to a maximum of 10%) (4) then this concentration of the solute will constitute the minimum detectable sample concentration. 

Now the maximum sample volume is l.log, (i.e. Vg), and the mass sensitivity given by equation (7) is 2ocX ). 

It is seen from equation (12) that the system concentration sensitivity is also directly (and this time solely) dependent on the detector sensitivity and is entirely independent of the column dimensions and efficiency. Consequently, in contrast to the system mass sensitivity, the system concentration sensitivity is not dependent on the detector dispersion. It should be noted, however, that the maximum permissible sample volume has to be employed to realize the maximum concentration sensitivity 

The maximum k at which a solute is eluted is also controlled by the detector sensitivity. As the k of an eluted solute increases, the peak becomes more disperse. As a result, the peak becomes smaller and ultimately, the peak will disappear into the detector noise. If it is merely necessary to unambiguously identify the existence of a peak, then the peak maximum would probably have to be five times the noise level. This is also an 

Vg is the volume of stationary phase in a theoretical plate K is the partition coefficient of the solute. 

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