Glutaric Acid: Properties, Preparation & Lab Protocols

Glutaric acid is a straight-chain, five-carbon aliphatic dicarboxylic acid widely used as a building block in polymer chemistry, cross-linking applications, and biochemical research.

Chemical Name

Glutaric acid (pentanedioic acid)

Molecular Formula

C₅H₈O₄

Molecular Weight

132.12 g/mol

CAS Number

110-94-1

Appearance

White crystalline powder

Solubility

Freely soluble in water and ethanol

SKU (Aladdin)

G420610

Physicochemical Properties of Glutaric Acid

Glutaric acid (pentanedioic acid, CAS 110-94-1) is a linear aliphatic dicarboxylic acid with the molecular formula C₅H₈O₄ and a molecular weight of 132.12 g/mol. It appears as a white crystalline solid and is freely soluble in water and polar organic solvents such as ethanol and acetone, making it highly versatile for aqueous and organic reaction systems.

The compound possesses two carboxylic acid functional groups separated by a three-carbon methylene chain, conferring moderate acidity. Its pKa values are reported to be approximately 4.3 (pKa1) and 5.4 (pKa2), which are relevant when preparing buffered solutions or conducting pH-sensitive reactions. The melting point is approximately 97–99 °C, and the compound is stable under standard laboratory storage conditions when kept in a cool, dry environment away from strong oxidizing agents.

Safe Handling and Storage Guidelines

Although glutaric acid is considered to have relatively low acute toxicity, standard laboratory precautions should be observed. Always wear appropriate personal protective equipment (PPE) including nitrile gloves, safety goggles, and a laboratory coat when handling the solid or its solutions. Avoid generating and inhaling dust during weighing operations; use a balance enclosure or fume hood where dust generation is likely.

Store glutaric acid in a tightly sealed container in a cool (15–25 °C), dry location, away from strong oxidizing agents and bases. The compound is not classified as a flammable solid under normal conditions, but fine powders may present a dust-explosion hazard in high concentrations. Consult the current Safety Data Sheet (SDS) for complete hazard information before use. Dispose of waste solutions in accordance with local chemical waste regulations.

Solution Preparation Protocol

Materials required: Glutaric acid (G420610), analytical balance, volumetric flask, appropriate solvent (ultrapure water or ethanol), magnetic stirrer, pH meter (if preparing buffered solutions).

Aqueous stock solution (e.g., 1 M):

1. Calculate the required mass: for 100 mL of 1 M solution, weigh 13.21 g of glutaric acid.
2. Transfer the weighed solid to an appropriately sized beaker containing approximately 70 mL of ultrapure water.
3. Stir on a magnetic stirrer at room temperature until the solid is completely dissolved. Warming to 40–50 °C may accelerate dissolution if required.
4. Transfer the solution quantitatively to a 100 mL volumetric flask and make up to volume with ultrapure water. Mix thoroughly.
5. If a specific pH is required, adjust with 1 M NaOH or 1 M HCl and verify with a calibrated pH meter.
6. Filter through a 0.22 µm membrane filter if sterile or particulate-free solutions are needed.
7. Label with compound name, concentration, date of preparation, and preparer's initials. Store at 4 °C; use within four weeks or as validated by the laboratory.

Common Laboratory Applications

Glutaric acid is employed across multiple research and industrial domains owing to its bifunctional carboxylic acid structure:

• Polymer and materials science: Used as a monomer or co-monomer in the synthesis of polyesters and polyamides, and as a plasticizer precursor.
• Cross-linking agent: Reacts with amine- or hydroxyl-bearing substrates to form stable amide or ester linkages; relevant in hydrogel preparation and surface functionalization.
• Biochemical and metabolic research: Serves as a reference standard or substrate in studies of fatty acid oxidation disorders, including glutaric aciduria type I, and in organic acid profiling by LC-MS or GC-MS.
• Analytical chemistry: Used as a calibration standard for ion chromatography and capillary electrophoresis of organic acids.
• Buffer preparation: The two pKa values of glutaric acid allow preparation of buffered solutions in the pH 3.5–6.5 range, useful for enzyme assays and chromatographic mobile phases.

Troubleshooting and Quality Considerations

Incomplete dissolution: If the solid does not fully dissolve at room temperature, gently warm the solution to 40–50 °C with stirring. Ensure the solvent volume is sufficient relative to the amount of solute.

pH drift: Glutaric acid is a moderately strong diprotic acid; even small residual amounts can significantly lower solution pH. Always verify pH after dissolution and adjust as required for the intended application.

Purity verification: For sensitive analytical applications such as metabolic profiling, confirm purity by HPLC or titrimetric assay before use. Aladdin Scientific provides lot-specific certificates of analysis (CoA) for product G420610.

Moisture uptake: Although glutaric acid is not highly hygroscopic, prolonged exposure to humid air may affect precise weighing. Store in a desiccated environment and allow cold-stored material to equilibrate to room temperature before opening.

Contamination: Use dedicated spatulas and glassware to prevent cross-contamination with other reagents, particularly amines or strong bases that may react with the carboxylic acid groups.

Frequently asked questions

What is the recommended storage condition for glutaric acid (G420610)?

Glutaric acid should be stored in a tightly sealed container at 15–25 °C in a cool, dry location away from strong oxidizing agents and bases. For long-term storage, a desiccated environment is advisable to minimize moisture uptake.

How do I prepare a 1 M aqueous solution of glutaric acid?

Weigh 13.21 g of glutaric acid (MW 132.12 g/mol) and dissolve in approximately 70 mL of ultrapure water with stirring. Transfer quantitatively to a 100 mL volumetric flask and make up to volume. Verify the pH and adjust if required for your application.

Can glutaric acid be used to prepare pH buffers?

Yes. Glutaric acid has two pKa values of approximately 4.3 and 5.4, making it suitable for preparing buffered solutions in the pH 3.5–6.5 range. Adjust the ratio of glutaric acid to its sodium salt with NaOH to achieve the desired pH, and confirm with a calibrated pH meter.

Is glutaric acid suitable for biological or metabolic research applications?

Yes. Glutaric acid is used as a reference standard and substrate in organic acid metabolic profiling by LC-MS and GC-MS, and in research related to fatty acid oxidation disorders such as glutaric aciduria type I. High-purity material such as Aladdin G420610 is recommended for quantitative analytical work.

What precautions should be taken when weighing glutaric acid?

Wear nitrile gloves, safety goggles, and a laboratory coat. Perform weighing in a balance enclosure or fume hood to minimize dust inhalation. Allow cold-stored material to reach room temperature before opening the container to prevent condensation and moisture uptake.

References

1. Lide, D. R. (Ed.). CRC Handbook of Chemistry and Physics, 97th Edition. CRC Press, Boca Raton, FL.
2. Sigma-Aldrich / Merck. Glutaric acid product specification and Safety Data Sheet. Retrieved from the Sigma-Aldrich online catalog.
3. Aladdin Scientific. Certificate of Analysis for Glutaric acid, SKU G420610. Aladdin Scientific, Shanghai.
4. Goodman, S. I.; Frerman, F. E. Organic acidemias due to defects in lysine oxidation: 2-ketoadipic acidemia and glutaric acidemia. In: Scriver et al. (Eds.), The Metabolic and Molecular Bases of Inherited Disease. McGraw-Hill.

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