Topics - Mass Sensitivity
Chromatography detectors are in general are either mass sensitive
or concentration sensitive
. A mass sensitive detector responds to the mass of solute passing through it per unity time and a concentration sensitive detector responds to the mass of the solute per unit volume of mobile phase passing through it. The flame ionization detector (FID) is mass sensitive whereas the UV detector is concentration sensitive. The advantage of the mass sensitive detector is that the column eluent can be diluted without affecting the detector response. This characteristic is particularly useful when using a capillary column as, for example, the mobile phase can pass directly into the hydrogen flow to the FID and although the column eluent is extensively diluted, because the FID is mass sensitive, the response of the detector is unaffected.