High-throughput technique with combinatorial sample

Cell migration was assayed by automated time-lapse video microscopy. In this technique, cells are imaged on the surfaces and the individual cell tracks are reconstructed from the position of each cell at successive time points. The automation enables time lapse videos to be taken from multiple locations on the same surface at the same time. Thus, the entire gradient can be imaged at once. This high-throughput technique combined with the combinatorial sample preparation enables the exploration of a relatively large parameter space quickly. 

The application of combinatorial principles in chemical synthesis, particularly in the search for active substances, requires analytical methods with high throughput (von dem Bussche-Hunnefeld et al. [1997]). Screening techniques can be used to analyse a large number of test samples in a short... 

Most of the techniques discussed above are typically used ex situ for catalyst characterization before and after reaction. This is normally the easiest way to carry out the experiments, and is often sufficient to acquire the required information. However, it is known that the reaction environment plays an important role in determining the structure and properties of working catalysts. Consequently, it is desirable to also try to perform catalytic studies under realistic conditions, either in situ [113,114,157, 191-193] or in the so-called operando mode, with simultaneous kinetics measurements [194-196], In addition, advances in high-throughput (also known as combinatorial) catalysis call for the fast and simultaneous analysis of a large number of catalytic samples [197,198], This represents a new direction for further research. 

It is generally accepted that an analysis by LC/UV/MS coupled with a H NMR is sufficient to characteri.se a compound and provide an estimation of purity. The massive increase in sample numbers through combinatorial approaches has led to an urgent need for the above techniques to be available to the chemist on demand. This has cataly.sed the development of high-throughput walk-up open-access LC/UV/MS systems. 

Library analysis becomes more complicated when the formation of stereo- or regio-isomers is possible, as the size of the library is increased by the number of possible isomers. In order to allow a rapid and uncomplicated evaluation, it is therefore important to design the library before synthesis such that the library size is restricted to a maximum of 15 to 20 possible compounds. It must be stressed that the MS investigations presented here have not fully explored the potency of either the mass spectrometric or the chromatographic techniques. The authors are conscious of the wealth of other experiments and possibilities to analyze fully a specific combinatorial library with optimized analytical techniques. Therefore, it is important to realize that in library analysis, compromises have to be made according to the priority of full sample characterization or high throughput. 

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