Description

 Acetic acid (CH₃COOH) is a simple carboxylic acid, often recognized as the main component of vinegar (which typically contains about 5–8% acetic acid by volume). It is a colorless, volatile liquid with a pungent odor and a strong acidic taste. Acetic acid is widely used in both industrial and laboratory applications due to its acidic properties, ability to act as a solvent, and its reactivity in organic synthesis.

Common Uses in a Biology Lab

• Buffering agent: Acetic acid is commonly used to prepare buffer solutions, particularly in combination with its conjugate base, acetate. These buffers are essential for maintaining pH stability in biological systems during experiments such as enzyme reactions, electrophoresis, and PCR (Polymerase Chain Reaction).
• Fixative in microscopy: It is often used as a fixative or part of a fixative solution, such as in Carnoy’s fixative, for preserving tissue samples in microscopy and histology studies. Acetic acid helps preserve the structure of biological specimens by crosslinking proteins.
• DNA/RNA extraction: Acetic acid is used in nucleic acid extraction procedures, particularly when working with biological samples such as cells or tissues. It helps in breaking down cellular structures, aiding in the release of nucleic acids like DNA and RNA for further analysis.
• pH adjustment: Acetic acid is used to adjust the pH of solutions, especially in laboratory experiments that require a slightly acidic environment for optimal enzyme activity or chemical reactions.
• Organic synthesis: In synthetic chemistry, acetic acid is used to produce a variety of chemicals, including acetic anhydride, acetate esters, and other organic compounds. It is also involved in esterification reactions in organic chemistry labs.
• Electrophoresis: In gel electrophoresis, acetic acid is used in the preparation of running buffers, such as in the agarose gel electrophoresis of DNA, where it helps control the pH and ensure proper separation.

Safety Hazards

• Corrosive: Acetic acid is a strong acid and can cause severe burns to the skin, eyes, and mucous membranes upon contact. It is essential to wear appropriate protective equipment, such as gloves, goggles, and lab coats, when handling acetic acid.
• Inhalation: Inhalation of acetic acid vapors or mist can irritate the respiratory tract, leading to coughing, difficulty breathing, and other respiratory symptoms. Adequate ventilation is essential, especially when working with larger quantities.
• Ingestion: Ingesting acetic acid can cause serious damage to the mouth, throat, esophagus, and stomach. It is toxic and should never be consumed.
• Environmental hazard: Acetic acid is not highly toxic to aquatic life in small amounts but can cause environmental damage if released in large quantities. It should be disposed of properly to prevent contamination of water sources.

Handling

• PPE: Always wear gloves, safety goggles, and a lab coat when handling acetic acid. Use appropriate respiratory protection, especially when working with concentrated acetic acid or in poorly ventilated areas.
• Ventilation: Work with acetic acid in a well-ventilated area or under a fume hood to avoid inhaling fumes. Avoid prolonged exposure to vapors.
• Storage: Store acetic acid in tightly sealed containers made of materials resistant to corrosion, such as glass or certain plastics. Keep it in a cool, dry location, away from heat sources and incompatible chemicals like strong bases and oxidizers.
• Disposal: Dispose of acetic acid according to local hazardous waste disposal regulations. Small amounts may be neutralized with a base, such as sodium bicarbonate, before disposal, but larger amounts require proper waste disposal methods to prevent harm to the environment.