How to Prepare Coomassie Destaining Solution

1. 1Work in fume hood throughout preparation
2. 2Add 500 mL distilled water to a 1 L graduated cylinder or volumetric flask
3. 3Add 300 mL methanol while swirling gently
4. 4Slowly add 100 mL glacial acetic acid dropwise while stirring continuously to prevent localized heating
5. 5Add distilled water to bring final volume to exactly 1 L
6. 6Mix thoroughly by inversion or gentle stirring
7. 7Allow solution to equilibrate for 10 minutes before use

Filter through 0.22 μm filter if sterile solution is required. Cannot autoclave due to methanol evaporation which would alter composition.

CRITICAL: Work in fume hood throughout preparation. Wear nitrile gloves, lab coat, and safety goggles. Glacial acetic acid vapors cause respiratory irritation. Methanol is toxic by inhalation and skin contact. Add acetic acid slowly to prevent violent bubbling and heat generation.

Store in tightly sealed glass bottle at room temperature away from heat sources. Label with preparation date. Replace if methanol odor weakens significantly, indicating evaporation has altered composition. Stable for 6 months when properly sealed.