Liquid Chromatography Detectors - The UV Detectors > The Fixed Wavelength UV Detector > Page 41
The zinc lamp has a major emission line at 213.9 but the emission line at 307.6 is of comparable intensity and a suitable filter would be needed if detection was required to be exclusively at the lower wavelength. The cadmium lamp has a major emission line at 228.8 but light is emitted at both lower wavelengths and at substantially higher wavelengths and so an appropriate filter would again be desirable. Suitable interference filters can be quite expensive to construct, which may account for the unpopularity of these two lamps. They do, however, emit light at wavelengths which would give an increased sensitivity to substances such as proteins and peptides, which might make their use worthwhile in the biotechnology field.
Figure 24 Emission Spectra for Three Discharge Lamps