Firstly, let us learn something about the adsorption mechanism of reversed-phase extraction and normal phase extraction. Reversed-phase extraction separation mainly uses the non-polar force between C-H bonds on SPE functional groups and C-H bonds of target compounds. In general, non-polar reversed-phase SPE columns are more suitable for extraction and separation of non-polar target compounds or target compounds with moderate polarity from polar matrices. Target compounds adsorbed on nonpolar SPE columns by nonpolar forces can be eluted with nonpolar solvents, such as chloroform, cyclohexane, and ethyl acetate. The target compound can be eluted from the SPE column successfully as long as the solvent elution strength is sufficient to destroy the van der Waals force between the target compound and the non-polar functional group of the adsorbent. Even methanol with strong polarity has sufficient nonpolar force to elute many compounds. Sometimes s...
When you look up the pharmacopoeia method, you may find that it only stipulates the bonding phase of column and the information of other columns is not available. Therefore, you may feel confused about how to choose a suitable column. Welch Materials, as the most professional chromatographic consumables manufacturers in China, would like to share with you some experience as follows. 01 Basic Knowledge of Column Chromatography is a separation analysis method, separation is the core, so the column which can achieve separation is like the heart of the chromatographic system. Common requirements for column are high column efficiency, good selectivity, fast analysis speed, etc. Packing materials for HPLC are mainly all-porous spherical silica gel, organic polymer matrix, core-shell silica gel, etc. The particle size is generally 3,5,7,10 µm, etc. And theoretical number of plates can reach 80,000 / m. 02 Selection of S...
1 Introduction of Column with Polymer Matrix Polymer matrix columns (Sugar-H, Sugar-Ca) may be contaminated, resulting in decreased column efficiency. Thus, flushing and regeneration are required. However, when flushing these columns with strong organic solvent, the column packing materials which exposed to some organic solvents will swell and column bed will be damaged. The swelling degree of the packing materials depends on the cross-linking degree of the polymer. Generally, the polymer whose cross-linking degree is higher than 8-10% has better physical stability. The shrinkage in the aqueous solution and the expansion in the organic solvent are both small, but limitation of using condition still need to be paid attention. 02 Daily Flushing 03 Regeneration and Flushing 04 Precaution 1. There is no need to worry that 85 °C is so high that it will damage the column. Activation and use of polymer matrix column ...
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