• A widely used aminosilane coupling agent: 3-Aminopropyltriethoxysilane, almost always abbreviated APTES, is one of the most widely used aminofunctional silanes in surface chemistry. It works as a coupling agent and surface-modifying reagent, bridging inorganic surfaces and organic chemistry. In practice it is used to functionalize glass, silica, and metal-oxide surfaces with reactive amine groups, creating an attachment point for dyes, polymers, proteins, and other molecules in applications ranging from adhesion promotion to biosensor and diagnostic surface preparation.
• How it works: The molecule has two reactive ends. The triethoxysilyl group hydrolyzes and condenses onto hydroxyl-bearing inorganic surfaces, anchoring the molecule firmly, while the primary amine at the other end remains available for further reaction. This gives a well-defined, amine-terminated surface that chemists can build on, which is why APTES is a standard starting point for silanization protocols in both research and manufacturing settings.
• Verified identity and purity: This TCI product (catalog A0439) is supplied at a minimum purity of 98.0% by GC, with molecular formula C9H23NO3Si and molecular weight 221.37, CAS number 919-30-2. It is a colorless liquid with a refractive index of about 1.42. These verified specifications let users confirm they are working with the correct, high-purity reagent, which matters because silanization results are sensitive to reagent quality and consistency.
• Storage and safe handling: APTES is moisture sensitive: exposure to atmospheric humidity can cause premature hydrolysis that reduces its coupling performance, so containers should be kept tightly closed and protected from moisture during storage. It ships as a corrosive amine liquid under DOT guidance and should be handled with appropriate protective equipment and ventilation. The Safety Data Sheet should be reviewed before use, and the product carries a California Prop 65 warning that should be noted.

Recommended For

• Silanizing glass, silica, and metal-oxide surfaces
• Adhesion promotion and coupling
• Surface functionalization with amine groups
• Research and industrial silane chemistry

Product Details

• Chemical name: 3-Aminopropyltriethoxysilane (APTES)
• Purity: Min. 98.0% (GC)
• CAS number: 919-30-2
• Molecular formula / weight: C9H23NO3Si / 221.37
• Physical state / color: Liquid / colorless
• Refractive index: ~1.42
• Condition to avoid: Moisture sensitive
• Manufacturer: TCI (catalog A0439)

Available Variants

• A0439-25G — 3-Aminopropyltriethoxysilane, 25 g
• A0439-100G — 3-Aminopropyltriethoxysilane, 100 g
• A0439-500G — 3-Aminopropyltriethoxysilane, 500 g
• The variants are the same reagent in different pack sizes, 25 g, 100 g, and 500 g, so you can match the quantity to your usage.

Primary Industries

• Materials science and surface chemistry
• Life science and diagnostics
• Adhesives and coatings
• Research laboratories

Standards and Certifications

• TSCA listed (per manufacturer data); California Prop 65 warning applies