The images below show the sample compartments of (from the left) a single and a double beam scanning UV-visible spectrophotometer. Note that the single beam instrument features a carousel, where up to nine samples can be mounted and measured in sequence. The double beam instrument features a more conventional arrangement, with a single cell in each of the sample (front) and reference (rear) beams. The image on the right shows a fixed wavelength (i.e. non-scanning) single beam instrument set up with a flow cell in its sample compartment.
The key features of a spectrophotometer sample compartment are: the optical paths through the compartment; the cell holders that locate samples in the optical path; and the lid that blocks out ambient light.
Cell Holders (Mounts)
The cell holders (or mounts) can accomodate different sizes of conventional cells (or cuvettes) for handling liquid and solution samples. The holders are often mounted on interchangeable bases, so that a variety of different accessories can be used. As one example, a heated cell holder can be used so that measurements can be performed at a range of different temperatures; such an arrangement might be used in kinetic studies, for example. Other holders (such as the one shown above right) are specifically designed to accomodate common sizes of test tube.
Cells (Cuvettes)
UV-Vis spectrophotometer: Light Sources | Wavelength Selector | Sample Compartment | Detector