Detectors:

A detector is an important part of the HPLC instrument and should be chosen very carefully for selective separation and accurate determination. The single most crucial factor is continuous detection based on the progress of separation of a component which may be immediately displayed and then recorded. However, a good detector must have following characteristics:

• It should have linear response to solute concentration in the range 0.1 µg/mL to 1 ng/mL.
• It will respond to solute just and not to the solvent or change in solute to solvent ratio.
• It should be insensitive to change in temperature, pressure and flow rate. Though highly sensitive detectors have been developed for HPLC but there is no universal detector which could be used for all kinds of samples and for all concentration ranges. The selection of a detector depends on the problem at hand though sometimes more than one detector may be used. These are of two primary types.