Single bead characterization using analytical constructs: application to quality control of libraries

Analytical construct technology has been successfully applied to the single-bead analysis of a split-mix combinatorial library. Substrates can be released from the resin by conventional cleavage for biological screening. Alternatively, for the purpose of analysis and quality control, cleavage at an orthogonal construct linker produces an analytical fragment incorporating the substrate. This analytical fragmnent is highly sensitized to electrospray mass spectrometry (ESI-MS) and is easily identified by isotope labeling. The construct cleavage rendered readily visible even those compounds that clearly could not be seen by conventional cleavage and mass spectrometry analysis. A 1H NMR control experiment proved that the compounds cleaved conventionally were, however, present in the sample in good yield and purity. In view of the data obtained, we think that this is a significant and important step toward solving our current quality control problems.