All samples, whether for chiral or achiral purification are screened using both HPLC and SFC.
Supercritical Fluid Chromatography (SFC) increases the rate at which we can both screen and purify. The Supercritical CO2 has a very low viscosity, allowing faster flow rates and therefore quicker run and equilibration times. An organic modifier, typically an alcohol, is mixed with the CO2 at varying percentages to control the retention time and resolution of the peaks.
On a preparative scale, in addition to the increased speed and faster flow rates, SFC offers faster dry down time as the CO2 is removed by the gas-liquid separator, leaving the sample in a reduced volume of alcohol. At Reach there are five preparative SFC systems powering 21 mm I.D columns, able to purify an average of 800 mg of material an hour per system.
We use a wide selection of columns from a variety of different Chiral Stationary Phase (CSP) manufacturers in our chiral screens. This ensures a larger proportion of chiral selectivity space is covered compared to screening methodologies which only employ one brand of column.
The choice of columns and amount of instrumentation in the laboratory allows tactical choices to be made as to which technique is pursued to ensure the fastest possible return to the client.
A UHPLC ensures that the client always receives high quality final purity data. Final compounds are all analysed on a UHPLC-MS system with diode array detection (DAD), allowing us to supply final purity data by UV and UV and MS spectra.