Citric Acid Monohydrate

CAS Number:

5949-29-1

Chemical / IUPAC Name:

2-hydroxypropane-1,2,3-tricarboxylic acid hydrate

INCI Name:

Citric Acid

EC Number:

201-069-1 (for anhydrous, monohydrate is derivative)

Molecular Formula:

C6H8O7·H2O

Molecular Weight:

210.14 g/mol

Other Names:

Citric acid monohydrate, 2-Hydroxy-1,2,3-propanetricarboxylic acid monohydrate

Uses:

Citric acid monohydrate is a weak organic acid that occurs naturally in citrus fruits . It is a white crystalline powder with a sour taste and is widely used across the food, cosmetic, and pharmaceutical industries .

· Cosmetics & Personal Care: Functions as a pH adjuster, chelating agent, and antioxidant. It helps maintain the desired acidity in creams, lotions, shampoos, and other formulations. It also binds metal ions that could otherwise destabilize products .

· Pharmaceuticals: Used as a pH-control agent, anticoagulant (through citrate salts), osmotic laxative, and in the treatment of dry mouth. It is also used to alkalinize urine and dissolve kidney stones. It is a component of some vaginal non-hormonal contraceptives .

· Food Industry: Widely used as a preservative, flavoring agent, and acidifier (food additive E330) in beverages, jams, jellies, and other food products .

· Laboratory & Research: Used in the preparation of citrate buffers for various applications including intravital microscopy and antigen/epitope unmasking. It also serves as an iron chelator in biochemical research .

· Industrial Applications: Used in textile, metal, and chemical industries for its chelating and pH-adjusting properties .

Origin

Citric acid monohydrate is a naturally-derived or synthetically produced compound. It is found naturally in citrus fruits such as lemons and limes . Commercial production typically involves fermentation of carbohydrates (such as molasses or corn) by the fungus Aspergillus niger, followed by purification and crystallization to form the monohydrate .

What does Citric Acid Monohydrate do in a formulation?

• pH Adjuster / Buffer: Controls and maintains the acidity of formulations. The pKa values are 3.13, 4.76, and 6.4 .
• Chelating Agent: Binds to metal ions (iron, copper, calcium), preventing them from catalyzing oxidation reactions or causing instability .
• Antioxidant Synergist: Works with other antioxidants to enhance their effectiveness by chelating pro-oxidant metals .
• Flavoring Agent: Imparts a characteristic sour, tart taste .
• Preservative: Inhibits microbial growth, particularly in acidic environments .
• Exfoliant: In skincare, provides mild chemical exfoliation (AHA) at appropriate concentrations .

Safety Profile:

· General Hazard Classification: Classified with GHS hazard statements H319 (Causes serious eye irritation) . Signal word: Warning .

· GRAS Status: Generally Recognized as Safe (GRAS) by the FDA for use in food when used in normal quantities .

· Concentration Limits: No specific regulatory limits for most applications, but typical use levels range from 0.1-5% depending on application .

· Irritation & Sensitization: Causes serious eye irritation. May cause mild skin irritation in sensitive individuals. Considered non-sensitizing .

· Toxicity: Low acute toxicity. Oral LD50 (rat): 3,000 mg/kg .

· Inhalation: Dust may cause respiratory tract irritation. Use of N95 dust mask recommended when handling powder .

· Breastfeeding Safety: Considered compatible with breastfeeding. It is a normal component of blood plasma and breast milk, and is rapidly metabolized .

· Handling & Storage: Store in a cool, dry place. Protect from moisture as it is efflorescent (may lose water of hydration) . Avoid contact with oxidizing agents, bases, and reducing agents .

· Regulatory Status: GRAS in the US. EU approved as food additive E330. Meets USP, Ph.Eur., and ACS specifications . EINECS-listed (201-069-1) .

Technical profile: