Gas Chromatography Detectors - Some Less Common GC Detectors > The Surface Potential Detector > Page 94

The Surface Potential Detector

The surface potential detector was developed by Griffiths and Phillips [47,48] in the early 1950s and consisted of a cell containing two parallel metal plates between which flowed the column eluent. One plate was mechanically attached to an oscillator that vibrated the plate at about 10 kHz. If the plates are identical, the surface charge on each plate is the same and so no potential is induced into the second plate by the vibrating plate. If however the surfaces are dissimilar, then the surface charge on each plate will differ and the vibrating plate will induce a potential on the other plate. A diagram of the detector is shown in figure 62.



Figure 62 The Surface Potential Detector