Combinatorial library gradient

Fig. 1 Illustration of a 2D continuous gradient combinatorial library that exhibits gradual and systematic changes in two variables...

Berry BC, Stafford CM, Pandya M, Lucas LA, Karim A, Fasolka MJ (2007) Versatile platform for creating gradient combinatorial libraries via modulated light exposure. Rev Sci Instrum 78 072202... 

W. K. Goetzinger, and J. N. Kyranos, Fast gradient RP-HPLC for high throughput quality control analysis of spatially addressable combinatorial libraries, Am. Lab. 30 (1998), 27-37. 

Figure 13.5. Mass-directed purification of a combinatorial library. Chromatographic separation was carried out using gradient elution of 10-90%acetonitrile in water for 7 min after an initial hold at 10%acetonitrilefor 1 min. (a)Total ion chromatogram showingdesired product and impurities, (b) Computer-reconstructed ion chromatogram (RIC) corresponding to the expected product, (c) Postpurification analysis of the isolated component with a purity >90%. (Reproduced from Ref 15 by permission of Elsevier Science.)...

Leroy, F., Presle, B., Verillon, F. and Verette, E. Fast generic-gradient reversed-phase high-performance liquid chromatography using short narrow-bore columns packed with small nonporous silica particles for the analysis of combinatorial libraries. ]. Chromatogr. Sci. 39 487-490, 2001. 

TA Berger, WH Wilson. High-speed screening of combinatorial libraries by gradient packed-column supercritical fluid chromatography. J Biochem Biophys Methods 43 127-134, 2000. 

Further improvement of throughput in LC-MS analysis may be achieved by step-gradient elution. This elution format is essentially an on-line solid-phase extraction (SPE) process, where the samples are loaded onto the column, washed with aqueous mobile phase to remove water soluble impurities, and compounds are eluted with a mobile phase of high organic content. The technique combines the simplicity of FIA with the benefit of the removal of impurities and buffer components before mass spectrometry detection. In this case, selectivity is achieved by mass spectrometry alone without chromatographic separation. The technique has been used for compound purity assessment and quantitation. An on-line back-flush SPE-MS technique has been used by Marshall for quality assessment of the combinatorial libraries [112]. This back-flush elution procedure provides a very effective in-line removal method... 

Goetzinger, W.K. Kyranos, J.N. Fast Gradient RP-HPLC for High-throughput Quality Control Analysis of Spatially Addressable Combinatorial Libraries, Am. Lab. 30, 27-37 (1998). 

Tolson, D. Organ, A. Shah, A. Development of a High-pressure Gradient Pumping System for Parallel Liquid Chromatography/Mass Spectrometry for the Analysis of Combinatorial Libraries, Rapid Commun. Mass Spectrom. 15, 1244-1249 (2001). 

Berger, T.A. Wilson, W.H. High-speed Screening of Combinatorial Libraries by Gradient Packed-column Supercritical Fluid Chromatography, J. Biochem. Biophys. Methods 43,77-85 (2000). 

To avoid bottlenecks in the analysis, each step should be automated. Automation of data acquisition is achieved by automated HPLC/UV/MS/ELSD instruments equipped with autosamplers that allow compounds to be batch analyzed in unattended fashion. Recently, fast generic HPLC methods have been implemented for analysis of combinatorial libraries [33-53]. Short columns (5 cm) and fast gradients (typically 3-10 min per sample) allow reaching throughput of 100-200 samples per day per instrument. 

Wilson WH and Berger TA, High-speed screening of combinatorial libraries by gradient packed-column supercritical fluid chtomatography, J. Biochem. and Biophys. Methods , Jan. 2000. J. Biochem. Biophys. Methods, vol. 43, No. s 1-3, E. Heftmann, Special Editor, Elsevier, New York 2000. 

Fig. 7. Composite of optical images of a T-fe combinatorial library of PS (M = 1800 g/mol) on silicon, t = 2 h, 25x magnification. Scale bar = 2.0 0.1 mm. The thickness scale is a power law function (given in text), reflecting the nonlinear thickness gradient deposition procedure. Adapted with permission from Ref 22.

Figure I. Combinatorial library with Pluracol (chain extender) composition and annealing temperature gradient. The oval marked an optimal region, selected for minimized water solubility and generation of microstructures.

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