The same oblique connection is employed at the exit end of the cell. The fluid flow along the cell axis must again change by nearly 360˚ and reverse its direction in order to pass out of the exit to waste. This type of cell design (with optimized geometry determined by experiment) dispersion resulting from Newtonian flow through the sensor cell can be practically eliminated. There remains, however, the dispersion that arises from the effect of the finite volume of the sensor relative to the volume of the eluted peak.
Apparent Dispersion from Detector Sensor Volume
Ideally the detector should monitor the instantaneous concentration of the solute as it laves the column. However, when monitoring an actual chromatographic separation, the sensor does not respond to the instantaneous concentration of solute in the column eluent but to the average concentration of solute in the sensing volume of the cell. This situation is depicted in figure 20.
Figure 20. Effect of Sensor Volume on Detector Output