Optimization of steady state recycling parameters utilizing polarimetry in chiral separations.

Processing gram to kilogram quantities of target analytes has led to the exploration of several high-throughput separation techniques. Among those investigated is steady state recycling (SSR). Similar to simulated moving bed (SMB) fractions are collected from the leading and trailing edges of a chromatographic profile while sample material is injected into the interior. Purifying large amounts of sample in the semi-preparative stage is ideal for these groups. SSR allows for development of methods capable of separating 50 g to kilograms and even greater amounts of product efficiently. Using polarimetry to optimize the SSR method further improves the efficiency of method development, providing comprehensive data leading to incisive development decisions. Accurate sample injection allowed continual 99% enantiomer separation after polarimetry optimization. We have developed an efficient SSR optimization methodology that offers rapid development of chiral separation by SSR.

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 100mg injection via preparative HPLC purification at 50mg/compound.