Solute Property Detectors:

These respond to a physical property of the solute that is not exhibited through the pure mobile phase. These are highly sensitive along with a detection signal for a few ng or even lesser amount of sample. For example absorbance, fluorescence, diffusion current and electrochemical detectors are considered in this category.

Besides low detection limit, a HPLC detector must meet following requirements:

• The selective response towards one or more classes of solutes.
• It must be small and compatible with liquid flow.
• It would have good stability and reproducibility.
• It has to be low dead volume to minimize extra-column band broadening.
• It has to be high reliability and ease of use.
• It has to be small response time, at least 10 times less than the peak width of a solute.
• It has to be a linear response to solute that extends over several orders of magnitude.