Abstract: The invention provides uncharged water-soluble silica-adsorbing polymers for suppressing electroendoosmotic flow and to reduce analyte-wall interactions in capillary electrophoresis. In one aspect of the invention, one or more of such polymers are employed as components of a separation medium for the separation of biomolecules, such as polynucleotides, polysaccharides, proteins, and the like, by capillary electrophoresis. Generally, such polymers are characterized by (i) water solubility over the temperature range between about 20.degree. C. to about 50.degree. C., (ii) concentration in a separation medium in the range between about 0.001% to about 10% (weight/volume), (iii) molecular weight in the range of about 5.times.10.sup.3 to about 1.times.10.sup.6 daltons, and (iv) absence of charged groups in an aqueous medium having pH in the range of about 6 to about 9.

Abstract: A method is provided for capping failure sequences in oligonucleotide synthesis by phosphitylation. A phosphite monoester is reacted with the 5' or 3' hydroxyl of the failure sequence between successive condensation steps in a synthesis procedure to form a 5' or 3' phosphite diester with the failure sequence. The phosphite diester substituent is inert with respect to subsequent reaction steps in the synthesis of the desired oligonucleotide product.