Spectrophotometer Design
David A. Harris · Garland Science eBooks · 2020
An ideal spectrophotometer lamp should produce a constant intensity of illumination over a wide range of wavelengths. Quartz–halogen and xenon lamps are commonly pulsed electronically. This has the additional advantage, to the operator, that the photochemical production of ozone is greatly reduced compared with a lamp giving continuous illumination. The cuvette and holder are positioned in a box with a light-tight lid, the sample compartment. Since, in modern instruments, the optical and electronic components are inaccessible, this is the region of the spectrophotometer/fluorometer which is most familiar to the user. Spectrophotometers may be fitted with various devices to handle multiple samples. An alternative route to the facile measurement of multiple samples uses a vertical, rather than horizontal light path. Modern spectrophotometers commonly compensate for differential emission either mechanically, by automatically varying slit width with wavelength, or electronically, by varying the gain on the photo-multiplier with wavelength.