Material Advantages of Plastic Bottles
In the laboratory, plastic bottles earn their status as "universal containers" thanks to the specific properties of three common materials:
PET: Lightweight and shatter-resistant; suitable for the short-term storage of weak acids and bases (e.g., 5% acetic acid, 10% ethanol).
HDPE: Highly corrosion-resistant; capable of holding strong oxidizers such as 30% hydrogen peroxide.
PP: High-temperature resistant (up to 120°C); capable of withstanding strong acids like concentrated hydrochloric acid (with the exception of hydrofluoric acid).
Keep These Reagents Away from Plastic Bottles
Even the seemingly "universal" plastic bottle will "melt down" or "disintegrate" when exposed to the following reagents:
Organic Solvents: Acetone and chloroform can dissolve the molecular chains of most plastics.
Strong Oxidizers: Concentrated nitric acid (above 68%) may cause the plastic material to become brittle.
Halogen Compounds: Bromine water can cause plastic bottles to swell and rupture.
Specialized Acids: Hydrofluoric acid-known for corroding glass-can penetrate plastic even more readily.
The Golden Rules for Safe Storage
Mastering the safe storage of reagents in plastic bottles comes down to remembering three key points:
Check the Label: The triangular recycling symbol on the bottom of the bottle (numbered 1 through 7) indicates the material type and its corresponding chemical resistance.
Test for Compatibility: When introducing a new reagent, perform a small-scale compatibility test over 24 hours to observe for any adverse reactions.
Replace Periodically: Even with compatible reagents, the storage container should be replaced every six months to ensure safety and integrity.