Figure 5.

UHPLC with UV–vis detection at λ = 210 nm for extracted films of (A) syringaldehyde, (B) vanillin, and (C) 4-hydroxybenzaldehyde (gray) before and (brown) after 3 h of exposure to 207 ppmv O₃(g) at 74% RH. Films extracted in isopropanol were dried and reconstituted in water before injection. Peaks labeled in each panel are listed in Table 1. The insets show the absorbance (Abs.) of each peak vs wavelength (λ) with colors matching the peak numbers in the corresponding panels.