Chromatographic silica gel 300-400 mesh is an adsorption and separation material widely used in chemical, pharmaceutical, petroleum, and other fields. Its core characteristics and applications are as follows:

I. Basic Characteristics

Physical Properties

1. Appearance: White powder or granular form with good fluidity.

2. Composition: Main component is silicon dioxide (SiO?·nH?O), with stable chemical properties.

3. Thermal Stability: Withstands temperatures up to 500–600°C, with a heating loss (150°C) of less than 5%.

Structural Parameters

1. Pore Type: Mostly coarse-pore silica gel, with a pore size of about 80–100 ? (8–10 nm) and a pore volume of 0.8–1 ml/g.

2. Specific Surface Area: 300–500 m2/g, providing high adsorption capacity.

II. Core Functions and Separation Principles

· Adsorption Mechanism: Based on the difference in interaction forces between the polarity of substances and the hydroxyl groups on the silica gel surface. Polar substances adsorb strongly with long retention times, while non-polar substances elute quickly.

· Separation Advantages: High separation efficiency and clear bands, suitable for fine purification of trace components.

III. Main Application Areas

1. Chemical and Petroleum Industries

o Dearomatization of petroleum products, selective separation of organic gases/liquids.

o Catalyst support and chromatographic carrier.

2. Pharmaceutical and Biological Fields

o Purification of active ingredients in Chinese herbal medicine, preparation of high-purity drugs.

o Separation of biological macromolecules such as proteins and nucleic acids.

3. Laboratory Analysis: Used as a stationary phase in column chromatography for qualitative and quantitative analysis of organic compounds or intermediates.

IV. Key Points for Product Selection

· Type Selection:

o Industrial Grade: Focuses on cost and large-scale separation, typically packaged in 20 kg/bags.

o Reagent Grade: Higher purity, suitable for scientific research experiments, commonly packaged in 500 g/bottles.

· Key Indicators: Pay attention to particle size uniformity (affects flow rate), moisture content (≤5% is ideal), and pore size matching the target molecule size.

V. Storage and Usage Precautions

· Storage: Store sealed in a dry place to avoid moisture absorption, which may reduce performance. Shelf life is typically 12 months.

· Regeneration: Can be reactivated by high-temperature drying (150°C) for multiple cycles of use.