Analyte detection

Analyte detection - context
Detection techniques - purpose
Chromatography - detector system
Detectors ... ?
Coupling chromatography & detectors
     Flame ionization detector (FID)
           General description of FID
           Illustration of FID
           Detailled description of FID
     Electron Capture Detector (ECD)
           General description of ECD
           Illustration of ECD
           Detailled description of ECD
     Comparison FID and ECD
           Type of detector
     UV-visible absorption detector
           General description of UV-vis-AD
                 UV frequency range
                 Principles of light absorption
                       Jablonski scheme
                 Chromophores
           Illustration of the UV-vis-AD
           Detailed description of UV-vis-AD
     Fluorescence detector (FD)
           General description of FD
                 Fluorescent light
           Illustration of FD
           Detailled description of FD
     Mass spectrometric detection (MSD)
           Brief description of MSD
End of lesson


Terminology

General description of UV-vis-D

 

operating principle:

  • measures the intensity of a monochromatic light-beam in the UV-visible frequency range that passes through a flow cell
  • the intensity decreases with increasing concentrations of the analyte that absorbs light at the given wavelength

for further information: principles of light absorption

well suited to detect analytes that contain 'chromophores'

 

advantages:

       • low limit of detection
and high selectivity		 Terminology
       • absorption spectra is analyte specific
and may be used for analyte identification
       • analyte is not destroyed

disadvantage:

       • background signal is 100% light transmission
(i.e., slight decreases in light intensity may be hard to detect)