Figure 5. Absorbance of retinol extracted from commercial 2 exposed to air for: a) 1 day, b) 3 days, c) 10 days, d) 18 days, e) 25 days and f) 32 days

Figure 5 shows the spectra obtained, in units of AU/mg, for the solid commercial sample (commercial 2) dried in air and exposed to air up for 32 days.