Minerals leached into drinking water from rubber stoppers.

Area of Science:

• Laboratory animal science
• Analytical chemistry
• Materials science

Background:

• Drinking water systems in animal research can introduce variability.
• Rubber stoppers are a potential source of mineral contamination in laboratory animal water.
• Leaching of minerals from stoppers into water requires investigation for experimental accuracy.

Purpose of the Study:

• To investigate mineral leaching from different rubber stoppers into drinking water.
• To determine the effect of water pH on mineral leaching from stoppers.
• To assess the suitability of commonly used stoppers for animal research.

Main Methods:

• Six types of rubber stoppers were tested with deionized and acidified deionized water.
• Water samples were analyzed for copper, magnesium, iron, manganese, zinc, chromium, and selenium using atomic absorption spectroscopy.
• Stopper compositions were also analyzed for mineral content.

Main Results:

• Minerals were detected in both the rubber stoppers and the water samples.
• Acidified water (pH 2.5) generally caused greater mineral leaching from stoppers compared to neutral water (pH 4.5).
• The commonly used black stopper leached measurable mineral levels but is deemed acceptable for general use.

Conclusions:

• Rubber stoppers can be a source of mineral contamination in animal research water.
• Water acidity significantly influences the extent of mineral leaching from stoppers.
• While common black stoppers are generally suitable, alternative stopper types may be preferred for specific nutritional or toxicological studies.