Final answer:
Quartz is the best material for a UV spectroscopy sample cell because it does not absorb UV light, allowing for accurate measurements.
Step-by-step explanation:
The best material for the sample cell for ultraviolet (UV) spectroscopy among the options given would be a. quartz. Quartz is preferred because it is transparent to UV light, meaning it does not absorb light in the UV range, which allows for accurate spectroscopic measurements.
Materials like glass and plastic can absorb UV light and therefore are not suitable for UV spectroscopy. While salts like KBr and NaCl can be used for infrared spectroscopy, they are not optimal for UV spectroscopy as they do not transmit UV light well. It is important to choose the correct material for the cell to ensure the accuracy of the spectroscopic analysis and to prevent interference from the cell itself.