Analysis of Non-Oligomeric Compound Libraries

Direct ES-MS characterization of a combinatorial library has been performed on the example of modified xanthene derivatives [30]. To circumvent the analysis of 104 to 10s possible compounds, small representative sublibraries rather than the whole library were synthesized and investigated [31].The results obtained were then extrapolated to the synthesis of the target library. A xanthene library was also used for ES-FT-ICR-MS investigation [32], A more recent contribution deals with the calculation of elemental compositions from FTICR mass spectra. FIowever,the mass accuracy required increases exponentially with the mass of the analyte [33], Therefore, elemental compositions are calculated from the exact measurement of fragment ions performing MS -experiments [34], 

Non-oligomeric compound libraries (200-600 Da) have also been investigated by MALDI [35]. Although the linear TOF analyzer is not well-suited to the measurement in the low mass ranges because of inherent problems with resolving power and interfering matrix effects, this contribution demonstrates the possibility of using MALDI in the analysis of combinatorial compounds. 

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