Parallel Chiral Column Screening with SFC

In chiral column screening, it is essential that the conditions for separating chiral substances are found quickly and effectively. As a result, many large pharmaceutical companies have recently decided to equip their chiral column screening departments with an 8x Sepmatix system. The 8x Sepmatix system for chiral column screening can separate a substance on eight different chiral separation columns simultaneously. This significantly increases sample throughput.

The standard system consists of three modules: an 8x FlowControl low-viscosity version with flow rates of between 0.25 to 1.50 ml/min; an autosampler with syringe pump which injects samples from standard microtiter plates or deep-well microtiter plates onto eight columns (also suitable for vial racks); and an 8x diode array detector with eight analytical flow cells applicable for the spectral range of 200 to 600 nanometers. The required space for the 8x Sepmatix system for chiral column screening is only 55 x 55 x 90 centimeters (W x d x h). The 8x Sepmatix system for chiral column screening can be fitted with the Sepmatix EluentRack, which is designed for a maximum of four solvent selection valves (each with six positions) and up to 24 solvent bottles (1 liter) or 18 fl asks (2.5 liters). the required space for the sepmatix eluentrack is 55 x 55 x 90 centimeters (W x d x h).

The demand for shorter runtime and reduction of solvents has rekindled the interest in the use of Supercritical Fluid Chromatography (SFC) for chiral separations. The goal was therefore to develop a parallel system for SFC screening based on the same proven parallel approach of the parallel LC screening system. The Chiral Screening Wizard Software that eases the evaluation of the screening process considerably should also be
applicable for the SFC screening results.

The following modifications allow the Sepmatix System to be used for SFC applications:

• a high pressure gradient system with a CO pump and a modifier pump
• increase of the temperature of the FlowControl to 40°C and optimization of the sealing material
• additional back pressure regulator (0-250 bar)

The separation of trans-Stilbene oxide was screened on eight columns (250 x 4.6 mm), using eight different solvent mixtures. Seven polysaccharide based chiral stationary phases (CSP) and one brush-type CSP were used. Particle size varied between 3 µm and 20 µm. With an equilibration time of 15 minutes and a runtime of 15 minutes, these 64 separations were done in four hours in the parallel mode. (Click image for larger picture)

With a few modifications the parallel LC system Sepmatix can also be used for Supercritical Fluid Chromatography. This new 8x parallel SFC system combines the advantages of SFC with its shorter runtimes and lesser use of solvents with the remarkably time saving of the parallel approach. Using the same detector and data format of the Sepmatix system, the Chiral Screening Wizard Software can be used for evaluation leading to a rapid finding of the optimal separation parameters. By the implementation of the 8x parallel Sepmatix LC system (Sepiatec, 2004) Chiral Column Screening could be carried through 8 times faster compared with conventional HPLC systems. The 8x parallel Sepmatix SFC System shown here increases the speed again - by a factor of 4-5.