Which material is used for sample cells in the visible light region?

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

Answer: (C)

In visible light measurements, the sample cell must be transparent across the visible wavelengths and not introduce extra absorption or background signals. Borosilicate glass fits this need well: it offers high transmittance throughout the visible spectrum, good chemical resistance to many solvents, and is inexpensive and easy to manufacture into precise cuvettes with a defined path length. Fused silica and quartz are excellent for ultraviolet transmission and still work in the visible, but they’re more costly and often reserved for UV-visible applications where UV transmission is required. Plastics can be used in some cases, but they tend to have higher background absorbance or autofluorescence and can be less chemically stable, which can compromise accuracy. So, borosilicate glass is the practical standard for sample cells in the visible region.