Fluorescence emission spectra of retinyl palmitate and all-trans-retinal. Structures and electronic transition assignments () for retinyl palmitate (A) and all-trans-retinal (B). Emission of retinyl palmitate (C) and all-trans-retinal (D-F, H, I, K, L, N, O) recorded in methanol (MeOH) ↔ and phosphate buffered saline (PBS), both with 0.6-1.2% DMSO; excitation wavelengths (λex) and concentrations (μM) are indicated. Recordings with MeOH (F) or PBS (G, J, M) alone are also presented. Bandpass slit: 6 nm for retinyl palmitate and all-trans-retinal in MeOH (λex 380 nm) and in PBS; 10 nm for all-trans-retinal (in MeOH λex 430 nm).