What causes quenching in fluorometry that leads to loss of linearity at high concentrations?

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Multiple Choice

What causes quenching in fluorometry that leads to loss of linearity at high concentrations?

When fluorophore concentration increases, the solution becomes optically dense enough that some of the emitted photons are reabsorbed by nearby molecules before they reach the detector. This self-absorption is a form of the inner filter effect, where the emitted light is attenuated as it travels through the sample. If the emission and absorption spectra overlap, more emitted light is lost with higher concentrations, so the detected fluorescence grows more slowly than concentration, breaking the linear relationship. This is the quenching mechanism described here. Other factors like instrument noise, photobleaching, or temperature changes can influence measurements, but they don’t specifically cause concentration-dependent loss of linearity through emission reabsorption.

When fluorophore concentration increases, the solution becomes optically dense enough that some of the emitted photons are reabsorbed by nearby molecules before they reach the detector. This self-absorption is a form of the inner filter effect, where the emitted light is attenuated as it travels through the sample. If the emission and absorption spectra overlap, more emitted light is lost with higher concentrations, so the detected fluorescence grows more slowly than concentration, breaking the linear relationship. This is the quenching mechanism described here. Other factors like instrument noise, photobleaching, or temperature changes can influence measurements, but they don’t specifically cause concentration-dependent loss of linearity through emission reabsorption.

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