Which technique is more sensitive than fluorometry?

• A. Chemiluminescence
• B. Ultraviolet spectroscopy
• C. Infrared spectroscopy
• D. Mass spectrometry

Answer: (A)

Sensitivity in detection methods depends on how much background noise affects the signal. Chemiluminescence emits light from a chemical reaction without needing external excitation light, so there’s very little background from the sample itself. That leads to an excellent signal-to-noise ratio and much lower detection limits, making it more sensitive than fluorometry, which requires exciting the sample and collecting emitted fluorescence. In fluorometry, autofluorescence, scattering, and other background signals can obscure faint signals, reducing sensitivity. Ultraviolet and infrared spectroscopy rely on absorption or vibrational signals that typically require higher analyte concentrations and thus are less sensitive. Mass spectrometry can be extremely sensitive in many cases, but for this comparison, chemiluminescence is the more sensitive option relative to fluorometry.