Spectrophotometers are often used with accessories such as cuvettes, which are rectangular or cylindrical containers designed for holding samples in optical analysis equipment. These containers may be made of transparent quartz, glass, or plastic. A quartz cuvette provides superior transmission properties, allowing efficient passage of light wavelengths for optimum measurement results. It is generally used for testing in the ultraviolet light range where glass and plastic become opaque. Glass and plastic are used for measurements in the visible light range.
Certain instruments use prisms to deviate light projected by the light source. Since the prism is a key optical component, the prism glass should be free from impurities and cracks. Most are triangular prisms, rather than rectangular or cube-shaped ones, such as a Wollaston prism.