Gas Chromatography Detectors - Summary of Detector Criteria > Page 21

 

It must be emphasized that detectors can not be compared on the basis of their noise or response. They can only be compared on the basis of their sensitivity or signal-to-noise ratio at a specific solute concentration.

 

6. Detector Sensitivity Minimum Detectable Concentration (MDC) (XD)-Detector sensitivity can also be defined as that concentration that will produce a signal equivalent to twice the noise or, as that change in the physical property being measured that will provide a signal equivalent to twice the noise. The sensitivity defined in concentration units is, in general, more useful to the analyst.

 

7.Detector Dispersion () This is generally not significant in GC detectors

 

8. Detector Time Constant (Dt) The overall time constant of the sensor and electronics is given in milliseconds. It is of interest in high speed chromatography.

 

9. Pressure Sensitivity - (DP) The pressure sensitivity of a detector is the output that results from unit change in pressure. It is usually specified in V/p.s.i. or V/kg/m2 . It is important in detector design.

10. Flow Sensitivity (DQ) The flow sensitivity is the output that results from unit change in flow rate. It is specified in V/ml/min. It is important in detector design.

11. Temperature Sensitivity (DT) Thetemperaturesensitivityisdefined as the output that results from 1oC change in temperature. It is given in V/oC.