Detectors:

The fluorescence signals for an analyte present at low concentration is weak. It is partly because of low photoluminescence efficiencies and partly since only a small fraction of the fluorescence radiation reaches the detector. Therefore the primary needs for the detector is in which it should be able to detect weak optical signals. Thus, photomultiplier tubes with their high sensitivity and low noise are preferred over easy phototubes. Therefore, the shortcoming of photomultiplier tubes is in which these are single channel detectors. One requires scanning the appropriate monochromator across the whole wavelength range to acquire a spectrum. This does not permit taking the spectra of transient species or short lived analytes. To circumvent this problem we require a multi channel instrument using an array of detectors.  In present past some instruments using charge coupled device (CCD) as detectors have been established and are likely to become common within future.