# Amino Silica Gel > modified silica gel used in chromatography **Wikidata**: [Q115221787](https://www.wikidata.org/wiki/Q115221787) **Source**: https://4ort.xyz/entity/amino-silica-gel ## Summary Amino Silica Gel is a modified silica gel specifically designed for use as a column-packing material in chromatography. It is a chemical substance and subclass of silica gel, which is a granular, vitreous, and porous form of synthetic amorphous silicon dioxide. ## Key Facts - **Primary Application:** Modified silica gel used in chromatography to separate chemical mixtures. - **Classification:** Instance of a chemical substance; subclass of column-packing material and silica gel. - **Aliases:** Also known as Amino Silica. - **Base Material:** Derived from silica gel, a synthetic amorphous form of silicon dioxide (SiO₂) with a cross-linked, porous network. - **Density:** 2.20 g · cm⁻³ (measured at 20 °C) for the base silica gel material. - **Thermal Stability:** The base material has a melting point of 3 110 °F and a boiling point of 4 046 °F at 760 mm Hg. - **Volatility:** Possesses a vapor pressure of 0 mm Hg, making it practically non-volatile. - **Safety Limits:** NIOSH sets a Time-Weighted Average (TWA) exposure limit of 6 mg · m⁻³ and an Immediately Dangerous to Life or Health (IDLH) limit of 3 000 mg · m⁻³ for the base material. - **Related Variants:** Part of a group of modified silica gels for chromatography that includes C18, C8, Cyano, and Phenyl silica gels. - **Key Identifiers (Base Material):** KEGG D06521; EC 272-489-0; NIOSH Pocket Guide ID 0552; UMLS C0074530. - **CAS Registry Numbers (Base Material):** 68855‑54‑9 (silica gel) and 112926‑00‑8 (silicon dioxide). ## FAQs ### What is Amino Silica Gel used for? Amino Silica Gel is used as a stationary phase in chromatography, specifically as a column-packing material to separate complex chemical mixtures. ### How does Amino Silica Gel differ from standard silica gel? While standard silica gel is widely used as a desiccant or absorbent, Amino Silica Gel is a modified form tailored for analytical chemistry to enhance selectivity in separating compounds. ### What are the physical properties of the material? As a form of silica gel, it is characterized by a granular, porous structure with a density of 2.20 g · cm⁻³, a melting point of 3 110 °F, and negligible volatility (0 mm Hg vapor pressure). ### Is Amino Silica Gel hazardous? Exposure to fine particles of the base silica gel material can be hazardous; NIOSH establishes a TWA exposure limit of 6 mg · m⁻³ and an IDLH limit of 3 000 mg · m⁻³. ### What other modified forms of silica gel exist? Amino Silica Gel is part of a family of modified gels that includes C18, C8, Cyano, and Phenyl silica gels, all used in chromatography. ## Why It Matters Amino Silica Gel plays a vital role in analytical chemistry by serving as a specialized stationary phase that enables the precise separation of complex mixtures. Its modification from standard silica gel allows for tailored selectivity, which is essential for accurate chemical analysis in research and industry. The material inherits the robust properties of silica gel—such as chemical inertness, high thermal stability (withstanding temperatures over 3 000 °F), and extremely low vapor pressure—making it safe and effective for use across a wide range of laboratory conditions. By facilitating high-performance liquid chromatography, Amino Silica Gel contributes to advancements in pharmaceuticals, environmental testing, and biochemical research. However, its utility is balanced by the need for safety protocols, as the inhalation of fine silica particles requires adherence to strict occupational exposure limits to protect health. ## Notable For - **Chromatography Specialization:** Modified specifically for use as a column-packing material in chromatography. - **Thermal Resilience:** Based on a material with a melting point of 3 110 °F and a boiling point of 4 046 °F. - **Non-Volatility:** Inherits a vapor pressure of 0 mm Hg, ensuring it does not evaporate under normal conditions. - **Functional Group Variants:** Distinguished as one of the key modified forms of silica gel, alongside C18, C8, Cyano, and Phenyl variants. - **Safety Regulation:** Subject to specific NIOSH exposure limits (TWA 6 mg · m⁻³, IDLH 3 000 mg · m⁻³) due to inhalation hazards associated with fine particles. ## Body ### Composition and Structure Amino Silica Gel is a chemical substance belonging to the class of synthetic amorphous silica. It is a subclass of silica gel, which is composed of a cross-linked network of silicon dioxide (SiO₂). This structure creates a granular, vitreous, and highly porous matrix. The "Amino" designation indicates that the base silica gel has been modified to introduce specific functional groups, altering its surface chemistry for chromatographic applications. ### Physical Properties The physical characteristics of Amino Silica Gel are derived from its parent material, silica gel. The base material has a density of 2.20 g · cm⁻³ when measured at 20 °C. It exhibits high thermal stability, with a melting point of 3 110 °F and a boiling point of 4 046 °F at a standard pressure of 760 mm Hg. Additionally, the material is practically non-volatile, with a vapor pressure of 0 mm Hg. The molecular mass of the base silica is reported as 60.1 Da. ### Classification and Related Materials Amino Silica Gel is classified as an instance of a chemical substance. It falls under the broader categories of gels, column-packing materials, and absorbents. It is specifically categorized as a modified form of silica gel. Other notable modified silica gels used in chromatography include C18, C8, Cyano, and Phenyl silica gels, all of which share the same base silica structure but differ in their surface functionalization. ### Applications The primary application of Amino Silica Gel is in chromatography, where it functions as a stationary phase to separate chemical mixtures. This modification allows for the precise analysis of complex compounds in analytical chemistry. The parent material, silica gel, is also widely used as a hygroscopic desiccant to absorb moisture and as an absorbent for gases and liquids in industrial processes. While unmodified silica gel is often found in packaging to protect moisture-sensitive goods like electronics and food, the Amino variant is specialized for scientific separation techniques. ### Safety and Exposure Limits Handling Amino Silica Gel requires attention to the safety guidelines associated with its parent material, silica gel. While the substance is chemically inert, exposure to fine particles can pose inhalation hazards. The National Institute for Occupational Safety and Health (NIOSH) has established a Time-Weighted Average (TWA) exposure limit of 6 mg · m⁻³ for an 8-hour workday. The Immediately Dangerous to Life or Health (IDLH) limit is set at 3 000 mg · m⁻³. These limits highlight the importance of proper ventilation and protective equipment when handling the material in particulate form. ### Identifiers and References Amino Silica Gel and its parent material are tracked by various international identifiers. The base silica gel is associated with CAS Registry Numbers 68855‑54‑9 and 112926‑00‑8. Other key identifiers include: - **KEGG:** D06521 - **EC Number:** 272-489-0 (also listed as 601-214-2) - **NIOSH Pocket Guide ID:** 0552 - **UMLS CUI:** C0074530 - **ECHA infocard:** 100.065.880 (for 68855‑54‑9) and 100.128.559 (for 112926‑00‑8) ### Visual Resources Visual representations of the base material typically illustrate its granular and porous nature. An example of silica gel in use is available via the following image: ![Silica gel indicator](https://commons.wikimedia.org/wiki/Special:FilePath/Indicating-silica-gel.png).