ABSTRACT
The lack of a sensitive, linear detector was probably the greatest single impediment to the evolution of LC in the years past. The development of LC detectors has proved to be far more difficult than the development of GC detectors. This is because the presence of very low concentrations of solute vapor in a gas modify the physical properties of the gas to a far greater extent than the same concentration of solute will modify the physical properties of a liquid. Nevertheless, despite the sensitivity problems, many LC detectors have been developed over the past thirty years based on a variety of different sensing principles. However, only about twelve of them can be used effectively for LC analyses and, of those twelve, only four are in general use. The four prevailing detectors are the UV detector (fixed and variable wavelength), the electrical conductivity detector, the fluorescence detector and the refractive index detector; they are employed in over 95% of all LC analytical applications. In this chapter only these four detectors will be described. For those readers requiring more information on detectors, two books are recommended (1,2). Both books are dedicated to the subject of LC detectors.
