Spatially dispersed strategy

Automated synthesis of peptide and oligonucleotide libraries was initiated about 10 years ago [4], Within the last three years, there has been much attention focused on the generation of combinatorial libraries of small molecules. As with biopolymers, the use of solid resin support was central to the advance of this field. In solid-phase synthesis, one of the reactants is covalently bound to the solid support and an excess of the other reactants may be used in each step to drive reactions to completion. Purification of the intermediates and final product is easily achieved through extensive washing of the resin after each chemical step. For the purpose of high throughput synthesis, cleavage of the final 

Recent literature contains a multitude of examples of synthetic organic methodologies which have been optimized and applied to the solid-phase synthesis of combinatorial libraries [2]. In fact, the production of a number of these libraries has been realized on such systems as the Multipin SPOC [8], the DIVERSOMER [9] and the OntoBLOCK [10], All three apparatuses allow the automated production of spatially dispersed combinatorial libraries and facilitate the isolation, identification, screening and archiving of single compounds in distinct physical locations which are crucial factors during lead discovery and optimization. 

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The OntoCODE system effectively combines the advantages of both the spatially dispersed and split and recombine strategies and allows the chemist to build large archiv-able combinatorial libraries with milligram quantities of each compound and without the need for chemical tagging. 

When spatial or time multiplexing is employed as a multidimensional separation strategy with a first dimension based on an electrokinetic separation mode, an inherent difficulty arises from the need for the first dimension separation channel to be intersected by one of more second dimension channels. Regardless of whether the first dimension separation is operated in a transient (e.g., CZE) or steady-state (e.g., lEF) mode, electric field lines extending into the intersecting channels result in dispersion of sample out of the first dimension channel, and ultimately to sample loss as diffusion... 

Some strategies for developing a polyol process capable of generating well-dispersed alloyed PtRu nanoparticles deposited on carbon supports have been also investigated. " Recently, Sau et alf reported how, by careful selection of the polyol, reaction pH, temperature, and modality of combining the reactants, it was possible to control not only the size and dispersion of the bimetallic nanoparticles but also the relative spatial distribution of the two elements. 

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