Diisobutyloctadecylchlorosilane CAS NO.162578-86-1 is a widely used surface modifier in chromatographic technology. It is mainly used for stationary phase modification of chromatography columns in reverse phase liquid chromatography (RP-HPLC). With its unique molecular structure and surface chemical properties, it can effectively improve the hydrophobicity, stability, and separation efficiency of the chromatography column. By chemically bonding with the silicone matrix, Diisobutyloctadecylchlorosilane CAS NO.162578-86-1 forms a stable hydrophobic barrier, effectively optimizing the separation performance of the chromatographic column.

1. Molecular structure and surface modification potential

The molecular structure of Diisobutyloctadecylchlorosilane CAS NO.162578-86-1 is divided into three main parts: octadecyl long chain, diisobutyl branched chain, and chlorosilane group. Each part plays a unique role in the surface modification mechanism:

1.1) Octadecyl Chain: Octadecyl chain (C18H37) is the core of hydrophobic structure, and this long-chain hydrocarbon provides strong hydrophobicity, suitable for selective separation of stationary phases in reverse phase chromatography columns. The presence of C18 chains enables it to form a hydrophobic layer on the surface of silica gel, effectively retaining non-polar molecules.

1.2) Diisobutyl Branch: The Diisobutyl structure increases steric hindrance in the molecular structure, reducing non-specific adsorption on the surface of the chromatographic column. This branched structure not only enhances the compactness of the hydrophobic layer arrangement, but also improves the uniformity of the stationary phase, ensuring the reproducibility of separation.

1.3) Chlorosilane group: Chlorosilane group (Si-Cl) is a key group for surface modification. It has strong chemical reactivity and can covalently bond with hydroxyl groups on the surface of silica gel. The chlorosilicon group hydrolyzes in the presence of water to generate active hydroxyl groups (Si-OH), which further form stable silicon oxygen bonds (Si-O-Si) with the substrate surface, thereby forming a durable stationary phase layer on the surface of the chromatographic column.

2. Surface modification mechanism

The surface modification of Diisobutyloctadecylchlorosilane CAS NO.162578-86-1 in chromatographic columns is mainly achieved through chemical reactions with silica gel matrix, with the following reaction steps:

2.1) Surface hydrolysis and activation

The surface of silica gel usually contains hydroxyl groups (Si-OH), which have chemical activity and are the main active sites for surface modification. In the initial stage of hydrolysis and surface activation, the Si-Cl groups in chlorosilanes react with Si-OH on the substrate to remove hydrogen chloride (HCl) and form silicon oxygen bonds (Si-O-Si):

Si-OH+R2Si-Cl→Si-O-Si-R2+HCl

The formation process of this silicon oxygen bond is very stable and can maintain bonding under extreme conditions such as high temperature and high pressure, ensuring the long-term effectiveness of the chromatographic column.

2.2) Formation of hydrophobic barrier

After completing the bonding, the octadecyl long chain of Diisobutyloctadecylchlorosilane CAS NO.162578-86-1 molecules arranges on the surface of the chromatographic column to form a hydrophobic barrier. The tight arrangement of long-chain hydrocarbons effectively shields the polar hydroxyl groups on the surface of the silicone matrix. As a result, the chromatographic column exhibits hydrophobicity as a whole, which is very advantageous for separating non-polar molecules. Meanwhile, the hydrophobic barrier effectively reduces the interaction with polar compounds and avoids the occurrence of peak tailing phenomenon.

2.3) Inhibition of spatial hindrance and non-specific adsorption

The diisobutyl branched structure exhibits significant spatial effects and forms steric hindrance in the surface modification layer. Unlike typical long-chain modifying groups, diisobutyl branched chains reduce intermolecular squeezing effects by increasing steric hindrance, preventing non-specific adsorption of the target analyte. This steric hindrance effect can also optimize the symmetry of chromatographic peaks, improve the separation and column efficiency of chromatographic columns.

2.4) Stability and reproducibility enhancement

The formation of silicon oxygen bonds endows the Diisobutyloctadecylchlorosilane CAS NO.162578-86-1 chromatographic column with extremely high chemical stability, especially in acidic and alkaline environments, which is particularly important for experiments with large changes in sample pH. The strong bonding between chlorosilane groups and the surface of silica gel ensures the chemical stability of the stationary phase, allowing the chromatographic column to maintain consistent performance over prolonged use. In addition, the presence of diisobutyl branches enhances the uniformity of the stationary phase, ensuring the reproducibility of chromatographic column separation

3. Advantages of surface modification

By modifying the surface of the chromatographic column with Diisobutyloctadecylchlorosilane CAS NO.162578-86-1, the performance of the column has been significantly improved, and its main advantages include the following:

3.1) High hydrophobicity and selectivity

The hydrophobic barrier layer formed by surface modification of Diisobutyloctadecylchlorosilane CAS NO.162578-86-1 makes the chromatographic column suitable for separating hydrophobic molecules in reverse phase chromatography. Compared to other surface modifiers, octadecyl has a long chain and strong hydrophobicity, which helps to retain and separate non-polar or moderately polar molecules.

3.2) Reduce tailing and improve peak shape

Due to the steric hindrance effect of diisobutyl groups, the Diisobutyloctadecylchlorosilane CAS NO.162578-86-1 modified surface effectively reduces the non-specific adsorption of analytes, reduces the tailing phenomenon of chromatographic peaks, and thus obtains more symmetrical peak shapes, which is suitable for the needs of high sensitivity and accurate analysis.

3.3) Acid alkali and high temperature performance

The stability of silicon oxygen bonds enables Diisobutyloctadecylchlorosilane CAS NO.162578-86-1 modified chromatography columns to remain durable under high temperature and high pressure conditions, and even work stably for a long time in acidic and alkaline environments. This characteristic is particularly suitable for analytical methods that require operation in complex solvent systems, such as drug analysis and environmental detection.

3.4) High reproducibility and consistency

The uniform Diisobutyloctadecylchlorosilane CAS NO.162578-86-1 modification layer on the surface reduces batch differences between chromatography columns, ensuring good reproducibility of performance across different columns, making it particularly suitable for demanding analytical scenarios such as quality control and regulatory testing.

Diisobutyloctadecylchlorosilane CAS NO.162578-86-1 has become an ideal surface modifier in reverse phase liquid chromatography columns due to its superior hydrophobicity, steric hindrance effect, and silicon oxygen bond stability. By chemically bonding with the surface of the silicone matrix, ODiBCS achieves stability and durability of the stationary phase layer, providing efficient, accurate, and durable separation effects for chromatographic analysis.

Editor : Alan Liu

Email: alan.liu@dakenchem.com