An amphoteric dissociation ion exchange separation medium, the surface of which is an amphoteric dissociationcovalently-modified layer. When an environmental pH value is lower than the isoelectric point, pIm, of the covalently-modified layer, the type of net charges on the surface of the covalently-modified layer is positive and the separation medium has the properties of an anion exchanger; when the environmental pH value is higher than the pIm, the type of net charges on the covalently-modified layer surface is negative and the separation medium has the properties of acation exchanger. The separation medium has the properties of an anion exchanger and a cation exchanger at both sides of the pIm, respectively. The pH of an eluent can be adjusted to allow the separation medium surface and the target substance to have the same type of net charges, so that the target substance can be released by electrostatic repulsion.

The present disclosure provides methods of improving the resolution of analytes by in electrophoretic separations using a gel by incorporating into the gel an effective amount of one or more tri- or tetra-hydroxyl quaternary ammonium compounds, or a mixture of such compounds.

Methods and apparatus for separating, concentrating and/or detecting molecules based on differences in binding affinity to a probe are provided. The molecules may be differentially modified. The molecules may be differentially methylated nucleic acids. The methods can be used in fields such as epigenetics or oncology to selectively concentrate or detect the presence of specific biomolecules or differentially modified biomolecules, to provide diagnostics for disorders such as fetal genetic disorders, to detect biomarkers in cancer, organ failure, disease states, infection or the like.

Aspects of the disclosure relate to liquid chromatography (e.g., HPLC) methods which enable high resolution separations of polynucleotides of various lengths, sequences, and/or base compositions in a highly tunable manner. In some embodiments, the disclosure describes liquid chromatographic methods for separating a nucleic acid (e.g., a polyadenylated nucleic acid, such as an mRNA) from a complex mixture by using multiple ion pairing agents in the same mobile phase system. Accordingly, in some embodiments methods described by the disclosure are useful for assessing the quality of pharmaceutical preparations comprising nucleic acids.

The present disclosure relates to fluidic systems and devices for processing, extracting, or purifying one or more analytes. These systems and devices can be used for processing samples and extracting nucleic acids, for example by isotachophoresis. In particular, the systems and related methods can allow for extraction of nucleic acids, including non-crosslinked nucleic acids, from samples such as tissue or cells. The systems and devices can also be used for multiplex parallel sample processing.

The present disclosure relates to fluidic systems and devices for processing, extracting, or purifying one or more analytes. These systems and devices can be used for processing samples and extracting nucleic acids, for example by isotachophoresis. In particular, the systems and related methods can allow for extraction of nucleic acids, including non-crosslinked nucleic acids, from samples such as tissue or cells. The systems and devices can also be used for multiplex parallel sample processing.

Aspects of the disclosure include methods for the preparation of a polynucleotide. In some embodiments, the method includes contacting a first polynucleotide composition including: a polynucleotide having a sequence of 7 or more nucleoside subunits and at least two of the nucleoside subunits are joined by a N3.fwdarw.P5 thiophosphoramidate inter-subunit linkage; and non-target synthetic products and reagents; with a multivalent cation salt to precipitate a polynucleotide salt including at least one multivalent cation counterion; and separating the polynucleotide salt from the contacted first polynucleotide composition to produce a second polynucleotide composition including the polynucleotide salt. In certain embodiments, the method further includes contacting the polynucleotide salt with a reverse phase chromatography support; and eluting from the chromatography support a third polynucleotide composition including the polynucleotide. Also provided are compositions including a salt of the polynucleotide including at least one multivalent cation counterion.

The present disclosure relates to multifunctional verification molecules, including molecules according to formula (I): G-L-(B).sub.K-Q-U, wherein G, L, B, K, Q, and U are defined herein. The present disclosure also relates to methods of preparing and using such multifunctional verification molecules to remove defective multifunctional molecules and to quantify synthetic yield.

The present invention relates to methods for purifying RNA by chromatography under high salt conditions, e.g. by hydrophobic interaction chromatography.

The invention inter alia pertains to an electrophoresis assisted method for purifying at least one charged target molecule, preferably a nucleic acid, from a sample. Moreover, a device for use in a method for purifying a charged target molecule by electrophoresis is provided.