Related Experiment Video
Updated: Sep 5, 2025

Analysis of Organochlorine Pesticides in a Soil Sample by a Modified QuEChERS Approach Using Ammonium Formate
Published on: January 20, 2023
Impregnation of preparative high-performance solid phase extraction chromatography columns by organophosphorus acid
Meher G Sanku1, Kerstin Forsberg1, Michael Svärd1
1Department of Chemical Engineering, KTH Royal Institute of Technology, Teknikringen 42, SE-11428 Stockholm, Sweden.
Abstract:
The flexible and reversible preparation of columns for use in high-performance solid phase extraction chromatography by physisorption of organophosphorus acid extractants has been investigated in detail. Two extractants have been evaluated, bis (2-ethyl-1-hexyl) phosphoric acid (HDEHP) and 2-ethyl-1-hexyl (2-ethyl-1-hexyl) phosphonic acid (HEHEHP), but the developed procedure should be broadly applicable to other extractants. The liquid-liquid solubility of the extractants in feed solvents consisting of aqueous ethanol solutions of varying composition has been determined. The total amount of adsorbed extractant has been quantified by complete desorption and elution with ethanol followed by acid-base titrimetry. Column impregnation with feed solutions of varying concentration in the undersaturated region has been systematically evaluated, and the influence of a subsequent water wash step has been explored. It is shown that to achieve a robust and reproducible physisorption, the adsorbed amount of extractant should be determined after the wash step, and care must be taken when using indirect methods of measurement. Equilibrium Langmuir-type adsorption isotherms as a function of the extractant concentration in the feed solution have been determined. Adsorption of HEHEHP is higher than HDEHP for equal feed compositions, but the solubility of HEHEHP is lower, resulting in approximately identical maximum coverage levels. The ability of the resulting columns to separate rare earth elements have been verified for a mixture of eight metals using a combined isocratic and gradient elution of nitric acid.
More Related Videos
Related Concept Videos
Gas Chromatography: Types of Columns and Stationary Phases
For an analyte to remain on the column for a sufficient amount of time, it must exhibit some level of compatibility (or...
Ion Exchange
High-Performance Liquid Chromatography: Elution Process
High-Performance Liquid Chromatography: Introduction
In HPLC, two phases play a critical role in the separation process:
Principles Of Column Chromatography
Analyte Adsorption and Distribution

