Detectors

After separating the components of the mixture it is necessary to detect them. As chromatography is often used as a quantitative technique it is essential to be familiar with the following terms:

• Universal detector: this responds to all compounds eluting from the column, irrespective of their composition.


• Selective/specific detector: this responds to certain elements or functional groups. This is a useful approach if the components of the mixture are known.


• Sensitivity: the ratio of detector signal to sample size (or detector response per amount of sample).


• Minimum detectable level (MDL): the amount of sample in which the peak height is at least twice the noise height.


• Linear dynamic range: the concentration range of the sample that is detectable and where the detector response is linear (between the MDL and detector saturation).