Marcus Kamande, Stian Kogler, Patrik Appelblad, Hanne Røberg-Larsen and Steven Ray Wilson
Section of Chemical Life Science, Department of Chemistry, University of Oslo, Norway
Email: Kamande.marcus@gmail.com
Sample preparation and clean up for biological samples often includes use of high amounts of plastics and solvent. Sample preparation can also be prone to human errors [1]. To minimize this, there is a need for better automation to reduce the usage of resources, limit human errors and increase the throughput. Here we apply on-line Automated Filtration and Filter Backflush (AFFL) with Solid Phase Extraction (SPE) [2] for determination of drugs in cell media with decreased material use and minimizing human error.
The method has been optimized for the detection of 90 different drugs in 10 minutes in both aqueous solutions and cell cultivation medium. Experimental variables, such as column temperature, gradient of the mobile phase and flow rate were optimized to improve analysis time, peak shape and chromatographic resolution.
The AFFL SPE system was found to have good reproducibility for peak shape (4% RSD) and retention time (0.04% RSD) over 50 injections for a 10-drug mixture in cell medium. The system has also been tested with up to 90 drugs in cell cultivation medium, showing good reproducibility for same day testing of analyte area and retention time e.g. shown with Loperamide 0.5% and 2% RSD, respectively. Initial results from 90 drugs in cell medium show the same promising results. The robustness of the system is under investigation and will be stress tested with over 1000 injections.
These initial results support the use of AFFL-SPE as a suitable option for automation to cut down on the use of plastics, solvents and minimize human error.
![the analytes are loaded onto the SPE using a loading mobile phase consisting of v/v 3% Methanol/97% water. Right: when loading is completed, the valve is switched and the mobile phase from the LC pump elutes the analytes of the SPE onto the column for separation. The benefits of using AFFL-SPE over SPE, is that the filter prevents materials that will clog the SPE and it is also backflushed, removing the material trapped on it [2].](https://www.kromatografisymposiet.no/wp-content/uploads/2026/01/P02_img1.gif)
Figure 1. AFFL-SPE using a 10-port switching valve. LEFT: the analytes are loaded onto the SPE using a loading mobile phase consisting of v/v 3% Methanol/97% water. Right: when loading is completed, the valve is switched and the mobile phase from the LC pump elutes the analytes of the SPE onto the column for separation. The benefits of using AFFL-SPE over SPE, is that the filter prevents materials that will clog the SPE and it is also backflushed, removing the material trapped on it [2].
References
[1] More et al. Crit Rev Anal Chem 2025 https://doi.org/10.1080/10408347.2024.2362707.
[2] Kogler et al. Anal Chem 2024 https://doi.org/10.1021/acs.analchem.4c02246