Final answer:
The difference between a fluorometer and a spectrophotometer is that a fluorometer measures the emitted fluorescent light from a sample while a spectrophotometer measures light transmission or absorption to determine substances' absorbance properties.
Step-by-step explanation:
The main difference between a fluorometer and a spectrophotometer lies in the type of light measurement each instrument conducts. A fluorometer is specialized for detecting the intensity of fluorescent light emitted by a sample after it has absorbed light. It typically uses filters or monochromators to select the excitation and emission wavelengths and then measures the fluorescent light at a 90-degree angle to reduce background interference. On the other hand, a spectrophotometer measures the amount of light that is transmitted through a sample or, alternatively, the light absorbed by the sample. It provides information about the absorbance properties of a substance by differentiating which wavelengths of light are absorbed, which is essential when determining the types of pigments in photosynthetic organisms, for example.
Additionally, advanced spectrofluorometers allow techniques like synchronous spectroscopy, where the excitation and emission monochromators are synchronized to maintain a constant wavelength difference (A\u03BB). This enables the detection of specific molecules based on their characteristic energy shifts post excitation.