Solid supports for on-line selection and concentration in immunoaffinity capillary electrophoresis

VIZIOLI, NM

Cartagena de Indias

Simposio; 21st Latin-American Symposium on Biotechnology, Biomedical, Biopharmaceutical, and Industrial Applications of Capillary Electrophoresis and Microchip Technology; 2015

Preconcentration techniques using solid supports in capillary electrophoresis are based on the coupling of a microcolumn at the inlet of the capillary for selection and concentration of compounds prior to their electrophoretic separation. Such devices, commonly known as ?analyte concentrators?, cannot only be used for concentration enrichment, isolation, or extraction of analytes but also to achieve microreactions, allowing the on-line analysis of reaction products. The selective adsorbents can be immobilized directly on a portion of the inner surface of the capillary wall, a membrane, beads, monolithic structures, or even a multibore capillary. In comparison with off-line solid phase extraction (SPE) columns, concentrators require lower sample volumes, only few microliters of organic solvent or buffers are consumed, the entire process is carried out in the CE instrument, and small quantity of sorbent material is needed, which make on-line SPE cheaper than the off-line one. In addition, sensitivity in CE is increased at least 100-fold, allowing the detection of analytes from 1 ng/mL with UV absorbance detector to 1 pg/mL with a LIF detector, and even femtograms per milliliter. Different examples of on-line concentrators, including those that use antibodies as affinity ligands, will be discussed during this presentation. Special attention will be paid to main factors influencing concentrator performance e.g., the solid support geometry, chemical properties of the sorbent, sample concentration, and volume of elution buffer. Finally, the potential of immunoaffinity CE will be demonstrated through the application of the concentrator device for quantifying a specific protein level in blood.