*2.2. Acetaldehyde Detection*

### 2.2.1. Reagents

Whatman Filter paper n.1 (thickness 180 μm), methyl red (C15H15N3O2), methyl red sodium salt (C15H14N3NaO2), methanol (CH3OH), Glycerol (C3H8O3) and sodium hydroxide (NaOH) were purchased from Merck.
