Recycling chromatography is a powerful technique that allows the separation of two closely eluting peaks by increasing the column bed length. The technique allows the eluted substances to be recycled after passing through the column. Thereby, critical peak pairs that elute together can be separated further with each cycle. A previously presented recycling system was upgraded by adding, two additional valves. This optimization enables 1) peak parking for removal of impurities from the target compounds and 2) re-injection of the peak pair back into the system for peak recycling. The versatility of the recycling system is greatly enhanced by this upgrade. In this application, the optimized recycling system was used to remove matrix components from CBG-rich cannabis extract, allowing subsequent separation of CBG (cannabigerol) and CBD (cannabidiol) for purification of CBG. By combining two separation techniques in one system, CBG was purified to a high degree of purity, increasing from 81 % to 100 %.
Chromatogram from recycling system; green dash line: switching peak trap valve; blue: UV1; red: UV2; orange dash line: threshold 5 mAU for the UV2; 4 ml/min; wavelength 228 nm; 100 µl injection of cannabis extract 10 mg/ml.
Extended setup for the recycling system
PurityChrom® 6 visualization of new set-up for recycling system. Red rectangle: system upgrade.
Structural formula of CBG
Structural formula of CBD
Method | Preparative HPLC |
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Mode | RP |
Substances | Cannabigerol (CBG), Cannabidiol (CBD) |
Key words | HPLC, Semi-preparative chromatography, preparative chromatography, RP, peak recycling, peak parking, matrix removal, cannabinoids, Cannabigerol (CBG), Cannabidiol (CBD) |
CAS number | 25654-31-3, 13956-29-1 |
Version | Version 1/ 11/2023 |
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