How does the component structure of a fluorometer differ from a spectrophotometer?

• A. Fluorometer uses two filters and can operate with a true zero blank; spectrophotometer requires a blank cuvette
• B. Fluorometer uses a single filter; spectrophotometer uses two filters
• C. Fluorometer does not require filters; spectrophotometer does
• D. Fluorometer uses a prism; spectrophotometer uses a diffraction grating

Answer: (D)

Fluorometers are built with two optical paths: one to excite the sample at a chosen wavelength and another to detect the emitted light at a different wavelength. This dual-path setup often uses dispersion elements that separate wavelengths in each path, and in many classic designs a prism is used to achieve this wavelength separation. Spectrophotometers, on the other hand, measure light that passes through a single path, selecting the measurement wavelength with one dispersive element—commonly a diffraction grating—so you’re looking at how much light at that one wavelength is absorbed.

So, the described difference reflects that dual-path, excitation-and-emission separation in fluorometers versus the single-path, absorption-focused design in spectrophotometers, which is why that option best captures the structural distinction.