Determination of relative fluorescence quantum yield

The relative fluorescence quantum yields for TEG-TC-ONOO^–, TEG-TC, DPPC-TC-ONOO^–, and DPPC-TC were determined using a previously reported equation⁷⁸ shown below:

where Q_s is the quantum yield of the unknown, Q_r is the quantum yield of a known dye, m_s and m_r are gradient of the plot of integrated fluorescence intensity against absorbance of the unknown and known dyes, respectively, and lastly, n (s and r) is the index of refraction. Absorbance (405 nm) and fluorescence intensity (λ_ex/em of 405/475 nm) were measured. Coumarin 343 was used as the reference standard for Q_r (0.63) in ethanol which was found directly from Sigma Aldrich. Ethanol was used for both the standard and the samples; the refractive index ratio is equal to 1. The quantum yields for TEG-TC-ONOO^–, TEG-TC, DPPC-TC-ONOO^–, and DPPC-TC were 0.08, 0.66, 0.09, and 0.64, respectively.