Parallel SFC/MS-MUX screening to assess enantiomeric purity.

Enantiomeric excess (ee) was evaluated for two internally synthesized compound libraries using a high-throughput automated, intelligent four-channel parallel supercritical fluid chromatography/mass spectrometry system equipped with a multiplexed ion source interface (SFC/MS-MUX). The two libraries contained compounds spanning a wide range of enantiomeric ratios with structurally diverse chemical scaffolds and stereogenic centers. The system analyzed each sample simultaneously against four chiral columns using up to six organic modifiers. Enhancements to our previously published parallel supercritical fluid chromatography/mass spectrometry system were implemented to address the challenges associated with automated trace enantiomer identification and quantitation. A reversal of enantiomer elution order was observed for several samples across multiple CSPs and modifiers. The relationship between elution order and % ee accuracy is presented for compounds exhibiting high, middle and low % ee values. Despite incidences in which the minor enantiomer eluted prior to the major enantiomer with less than baseline resolution, the overall % ee was in agreement with separations in which full baseline resolution was achieved. The methods presented here demonstrate the value and utility of high-throughput ee determinations to support drug discovery and development programs.

Laskar DB ，Zeng L ，Xu R ，Kassel DB ... -  《-》

Parallel supercritical fluid chromatography/mass spectrometry system for high-throughput enantioselective optimization and separation.

Zeng L ，Xu R ，Laskar DB ，Kassel DB ... -  《JOURNAL OF CHROMATOGRAPHY A》

Two-dimensional supercritical fluid chromatography/mass spectrometry for the enantiomeric analysis and purification of pharmaceutical samples.

A new analytical two-dimensional supercritical fluid chromatography/mass spectrometry system (2D SFC/SFC/MS) has been designed and implemented to enhance the efficiency and quality of analytical support in drug discovery. The system consists of a Berger analytical SFC pump and a modifier pump, a Waters ZQ 2000 mass spectrometer, a set of switching valves, and a custom software program. The system integrates achiral and chiral separations into a single run to perform enantiomeric analysis and separation of a racemic compound from a complex mixture without prior clean up. The achiral chromatography in the first dimension separates the racemate from all other impurities, such as un-reacted starting materials and by-products. Mass-triggered fractionation is used to selectively fractionate the targeted racemic compound based on its molecular weight. The purified racemate from the achiral chromatography in the first dimension is then transferred to the chiral column in the second dimension to conduct the enantiomeric separation and analysis. A control software program, we coined SFC2D, was developed and integrated with MassLynx to retrieve acquisition status, current sample information, and real time mass spectrometric data as they are acquired. The SFC2D program also monitors the target ion signal to carry out mass-triggered fractionation by switching the valve to fractionate the desired peak. The 2D SFC/SFC/MS system uses one CO(2) pump and one modifier pump for both first and second dimension chromatographic separations using either gradient or isocratic elution. Similarly, a preparative 2D SFC/SFC/MS system has been constructed by modifying an existing Waters preparative LC/MS system. All components except the back pressure regulator are from the original LC/MS system. Applications of the 2D SFC/SFC/MS methods to the separation and the analysis of racemic pharmaceutical samples in complex mixtures demonstrated that an achiral separation (in first dimension) and a chiral separation (in second dimension) can be successfully combined into a single, streamlined process both in analytical and preparative scale.

Zeng L ，Xu R ，Zhang Y ，Kassel DB ... -  《-》

Comparison of LC/MS and SFC/MS for screening of a large and diverse library of pharmaceutically relevant compounds.

Pinkston JD ，Wen D ，Morand KL ，Tirey DA ，Stanton DT ... -  《ANALYTICAL CHEMISTRY》

Automated approach for the rapid identification of purification conditions using a unified, walk-up high performance liquid chromatography/supercritical fluid chromatography/mass spectrometry screening system.

Aurigemma CM ，Farrell WP ，Simpkins J ，Bayliss M ，Alimuddin M ，Wang W ... -  《-》