Preparation of two amide‐bonded stationary phases and comparative evaluation under mixed‐mode chromatography

Abstract

In this work, the conventional reactions were used to functionalize the silica surface with amide and hydrocarbon chain groups affording two different mixed‐mode stationary phases (Sil‐amide‐C11 and Sil‐C12‐amide). The prepared stationary phases were analyzed by elemental analysis and thermogravimetric analysis. The retention of benzene, phenol, pyridine, and aniline was investigated and compared with synthesized and commercial columns, and this led to prove the existence of different interactions on the synthesized stationary phases. The mixed‐mode stationary phases showed multiple interactions, and different chromatography modes were found under distinct chromatographic conditions. According to the type of amide group (either free or within the hydrocarbon chain), different interactions can be made on the columns. The alkylbenzenes and polycyclic aromatic hydrocarbons, as nonpolar hydrocarbons, were chromatographed under reversed‐phase liquid chromatography modes, in which amide groups on the silica could efficiently separate polar analytes under hydrophilic interaction liquid chromatography mode in both prepared stationary phases. The performance of the columns was compared by the separation of the carboxylic acid group and biological samples. The bonding method and the type of amide group showed different interactions leading to different separation and performance.

Recent Developments of Liquid Chromatography Stationary Phases for Compound Separation: From Proteins to Small Organic Compounds

“…Larger charge density compounds elute faster than the low ones. Mixed-mode chromatography (MMC) [ 8 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ] is a system that can be used for at least two types of chromatography depending on the measurement conditions, especially in the mobile phase. Multi-column chromatography (MCC) is used to separate compounds from complex matrices utilizing a combination of the three separation principles above.…”

Preparation and chromatographic evaluation of a mixed polymer brush–silica stationary phase with temperature-sensitive property

“…Nowadays, mixed-mode chromatography with multiple retention and excellent separation efficiency has been achieved in one column to separate various types of substances. 10–14…”

“…Nowadays, mixed-mode chromatography with multiple retention and excellent separation efficiency has been achieved in one column to separate various types of substances. [10][11][12][13][14] Also in HPLC, the conventional liquid column usually relies on changing the composition of the mobile phase to modulate separation efficiency, but this method is tedious and requires a lot of time to balance the column in the separation process. At present, temperature-sensitive polymers are known as intelligent systems because they can reversibly become hydrated or dehydrated below or above their lower critical solution temperature (LCST).…”