Automated analytical/preparative high-performance liquid chromatography mass spectrometry system for the rapid characterization and purification of compound libraries

A fully automated analytical and preparative HPLC-MS system has been developed and applied to the characterization and purification of compound libraries derived by parallel synthesis. Our automated LC-MS system incorporates fast, reversed-phase C-18 HPLC (5-10 min analyses) and electrospray ionization mass spectrometry (ESI-MS). Post-data acquisition purity assessment of compound libraries is performed automatically using applescripts. Compounds falling below a threshold level of purity (<<90%) are subjected to automated on-line preparative HPLC-MS (i.e., PrepLCMS) purification. PrepLCMS is a method that we developed and is the first mass spectrometry-based system that permits automated and rapid purification of multimilligram quantities of compound libraries using a mass spectrometer to 'signal' fraction collection. The method utilizes real-time mass spectrometric ion signals to trigger fraction collection and only the mass(es) of the compound(s) identified by the user in the data acquisition method are collected. This one-sample-one-fraction format means that 'batches' of compounds can be purified without the need for excessively large fraction collector beds. Further, this eliminates the need for post-purification analysis or pooling of fractions collected, typically associated with other preparative purification techniques. This technique was designed for use by the chemist in an 'open access'-like environment, and has been successfully implemented for automated and unattended batch purifications of large numbers of compound libraries derived by parallel synthetic strategies. The results for several compound libraries, synthesized and purified at the multimilligram level by automated PrepLCMS are presented. (C) 1998 Published by Elsevier Science B.V.