ABSTRACT
This chapter provides the description of ultraviolet/visible (UV/VIS) analyzers and discusses near-infrared analyzers. It deals with some theoretical discussions of the principles of ultraviolet (UV) radiation, which are followed by the explanation of the different analyzer configurations and of their main components. Ultraviolet, visible, and near-infrared photometers and spectrophotometers are widely used in the process industry. Online UV analyzers have been used since the 1940s. Nanometer units are commonly used in the UV/VIS region, while micrometers or microns are normally used in the near IR region. The UV spectrum of typical absorbers illustrates the characteristic of the spectra shape found for absorbers in this region and is notably different from the spectra of absorbers in the infrared region. The split-beam UV analyzer uses a single-beam optical system relative to the sample cell. Deuterium arc sources provide a broad band of UV radiation at all of the wavelengths in the UV region.
