Molecular Libraries Screening Instrumentation

FIA-MS-MS in parent or neutral loss mode on triple quad instruments can also be applied to screen mixtures of unknown compounds quite rapidly, so that compound classes can be recognised. Yet despite the information about molecular weight and the structural information by product ions, MS-data systems in their commercial form up to the mid-1990s provided no structural information for identification purposes in the form of libraries comparable with the NIST-library of El spectra in GC-MS analysis. It can be hoped that troubles arising out of the lack of computer-searchable library data for identification will be overcome with the gradual increase in trap applications in MS-MS mode. The situation in identification is set to change [36]. 

Furthermore, it is possible today to enter the field of combinatorial chemistry relatively easily, and achieve the immense economies of scale shown in Table 24.1. For example, it is possible to buy ready-made combinatorial libraries built around specific molecular themes and consisting of many thousands of compounds, and it is also possible to create a high-throughput screening system for that library using automated, off-the-shelf instrumentation. This may enable one to be using combinatorial chemistry very quickly, and is one of the key characteristics of the field today it can be considered a commodity, available to anyone for a modest capital cost. 

Although automated solid-phase instruments are increasingly being used to construct biopolymers, manual synthesis is still used extensively with methods that are used to create molecular diversity (see Chapter 15). The libraries of molecules produced by these methods are often used for screening against biological targets. 

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