Automated post-collection concentration for purified preparative fractions via solid phase extraction

Recent advancements in preparative HPLC have improved and streamlined compound purification. However, fraction evaporation remains a bottleneck within the process. An alternative to fraction evaporation is to remove the water and reduce the overall volume of the collection by trapping the fraction onto a solid phase extraction (SPE) cartridge. This method (as opposed to analytical applications involving SPE) works by collecting and then diluting the fraction(s), passing the fraction(s) through a SPE, drying the SPE with nitrogen and ultimately eluting the concentrated fraction(s) in a small amount of 100% organic solvent. An appreciable breakthrough is not observed using this method. In addition, recovery from the SPE for the tested compounds rosmarinic acid and carvacrol, two naturally occurring antioxidants in oregano, was found to be 95–98% for a 100 mg injection via preparative HPLC purification at 50 mg/compound.