Pressure Sensitivity

The pressure sensitivity of a detector is one factor that determines the long-term noise. It is defined as the change in detector output for unit change in sensor-cell pressure. This specification is not critical for chiral chromatography as the katharometer (the detector most sensitive to pressure changes) is rarely (if ever) used. The maximum pressure that the detector can tolerate is also important, particularly when multicolumn systems are employed and the detector is at the inlet pressure of the second column.

Flow Sensitivity

Flow sensitivity is defined as the change in detector output for unit change in flow rate through the sensor cell. The response of the FID is virtually unaffected by flow rate changes and, in fact, only responds to the mass of solute passing through it per unit time. In contrast, the katharometer is very sensitive to changes in flow rate and (if used) requires to be operated with a reference cell to compensate for any fluctuations in column rate.

Temperature Sensitivity

All GC detectors are thermostatted in their own oven and, thus, are relatively insensitive to changes in ambient temperature.