Fig 4. Quenching by acrylamide of SP-B analogue tryptophan fluorescence emission in synthetic surfactant.

The ratio of fluorescence emission in the absence (F₀) and in the presence (F) of acrylamide is plotted as a function of quencher concentration (λ_ex = 280 nm, λ_em = 340 nm, 20 ± 0.5°C). Experiments were carried out in triplicate and are reported as average ± SE. The solid line represents the fit to a linear regression, yielding R² > 0.996 and a Stern-Volmer coefficient K_SV = 7.76 ± 0.14 M^-1.