For UV and IR spectral measurements, which material is commonly used for sample cells?

• A. Fused silica
• B. Plastic
• C. Borosilicate Glass
• D. Quartz

Answer: (A)

The ability to measure across UV and IR hinges on the cell material being transparent over those wavelengths and chemically stable. Fused silica provides broad transmission from the deep UV through the visible and into the near‑infrared, with minimal absorption in that range. It can be made into thin, optically polished windows and resists many solvents, making it a versatile and reliable choice for UV–Vis and near‑IR sample cells. Plastics tend to absorb UV light and can degrade or contaminate samples, while borosilicate glass blocks much of the UV and doesn’t transmit well in the IR. For measurements that extend into the far IR, other window materials such as CaF2 or ZnSe are preferred, but for UV and near‑IR applications fused silica is commonly used.