Applications of capillary electrophoresis to environmentally interesting molecules and single-component combinatory libraries

Capillary Electrophoresis (CE) is a powerful analytical tool that has been applied to different areas. In this light, the separation of environmental interesting molecules with a novel type of running buffer additives and the application of CE to combinatorial libraries have been developed. Molecular modeling results are used to interpret the separation behavior. p-Carboxyethyl calix[n]arenes, a series of moderately water soluble, multiple charged macrocyclic compounds that possess a basket shape are added to the running buffer to separate native and substituted polycyclic aromatic hydrocarbons, amino alcohols and vitamers. The separations are based on the differential distribution of analytes between a running buffer phase, which is transported by electroosmotic flow, and an electrophoretically mediated calix[n]arene. The cavity size and geometry of the calix[n]arene are investigated to their separation performance. The influences of pH, organic solvent and field strength on elution range, capacity factors, efficiency, and selectivity are also studied. The potential utility of CE as analysis and biological activity screening method for rapid screening of single component combinatory libraries is demonstrated by mimicking a 5 x 5 drug matrix. Twenty-five compounds that include biotin are selected as the test analytes and avidin is treated as the biological activity screening reagent. Five mixtures of 9 components each are created at the diagonal of the matrix by pooling each component from the same column and row for rapid screening. After obtaining optimum separation conditions, affinity CE produces the locations of the potentially active components based on changes in peak area. Blind tests are conducted that successfully locate the active component(s). High speed, high resolving power and small sample consumption are unique advantages of CE over other analytical tools for this application.