Liquid Chromatography Detectors - Dispersion in Detector Sensors > Dispersion in the Detector Sensor Volume > Apparent Dispersion from Detector Sensor Volume > Page 14

 

 

Figure 8 The Effect of Detector Sensor Volume on the Resolution of Two Solutes

 

The example given, is, by far, not the worst case scenario, but is a condition where the detector sensing volume has a very serious effect on the peak profile and, consequently, the resolution. The small bore column produces peaks having relatively small volumes and which are commensurate with the volume of the sensing cell. From figure 8, it is seen that even a sensor volume as small as 1 ml will have a significant effect on the peak width and the maximum resolution will not be obtained from the column. It is clear that the sensor cell volume must be no greater than 2 ml if the column performance is not to be denigrated to a significant extent. To emphasize the effect of cell volume, it should be noted that the results from a sensor cell having a volume of 5 ml are virtually useless. Unfortunately, many commercially available detectors have sensor volumes as great as, if not greater than 5 ml. If small bore columns are to be employed, such sensor volumes must be carefully avoided.