Cation exchange nucleoside separation

Dowex 50W-X4 1.1 0.80 Strongly acidic cation exchanger with S-DVB matrix for separation of amino acids, nucleosides and cations. Molecular weight exclusion is < 1400. 

Figure 8.24 Separation of the major deoxyribonucleosides and their 5 - monophosphate deoxynucleotides on a strong cation exchange column (column one) and a reversed-phase column. The unseparated nucleosides. A, on the ion- exchange column were switched to the reversed-ptose column. Pe2dc Identification A = nucleosides, B d-CMP, C d-AMP, D - d-GJIP, E - d-CVD, P d-UKO, G THD, and H = d-AOO. (Reproduced with permission from ref. 298. Copyright Preston Publications, Inc.)...

In addition to classical reverse phase separation of peptides on octadecyl derivatized silica monoliths, sugars and peptides as well as proteins and nucleosides have been analyzed on a 20-cm-long silica-based poly(acrylic acid) column (ID. 200 pm), employing HILIC and weak cation-exchange chromatography, respectively [194]. Furthermore, HILIC fractionation of polysaccharides delivered remarkable and promising results [84,194]. 

Uziele/ al. (U5) used porous divinyl benzene cation-exchange resins to separate the four nucleoside hydrolysates of RNA. Burtis et al. (B34, B35) used a smaller particle cation-exchange material for this separation and also investigated the various parameters that affected the separations. 

Several functional groups have been used to obtain cellulose anion exchangers [aminoethyl (AE), diethyl-aminoethyl (DEAE)], or cation exchangers [car-boxymethyl (CM), phosphate (P)] for thin-layer chromatography. PEI cellulose is not a chemically modified cellulose, but a complex of cellulose with polyethyleneimine. These cellulose exchangers are particularly useful for the separation of proteins, aminoacids, enzymes, nucleobases, nucleosides, nucleotides, and nucleic acids. 

In the past HPLC separations of nucleosides have been carried out in a variety of modes, including anion-exchange (Floridi et al., 1977) and cation-exchange (Breter et al., 1977) however, since the introduction of stable packings reversed phase has become the preferred method. Typical chromatographic conditions for the separation of nucleosides include the use of dilute phosphate buffers with organic modifiers such as methanol or acetonitrile on ODS stationary phases. The effects of variations in these parameters is described below. 

Column Chromatography — A model has been developed that closely predicts the elution of salt and sucrose during preparative chromatography on Na -form cation-exchange resin. It required minor adjustment for application to beet molasses due to an induced change in the resin from Na - to K -form, but was less accurate when the load of molasses containing 32% w/v dry matter was increased beyond 10% of bed volume. The binding of nucleosides and nucleotides to boronate affinity columns at pH 7 was enhanced by fluoride ion (and to some extent chloride ion) in the eluant, due to the formation of tetravalent fluoroboronate species. As a consequence, an improved separation of adenosine from 2 -deoxyadenosine was achieved. ... 

The hydrophobic properties of a series of 5-aIl l-, 5-alkenyl- and 5-alI yl-substituted deoxyuridines were defined from their retention behaivour on silica and reversed-phase columns. Zeatin and its riboside were determined in plant tissues by solid-phase extraction and cation-exchange h.p.l.c. Sugar and nucleoside H-phosphonates have been separated by anion-exchange h.p.l.c., and by flow injection analysis in which the components are hydrolysed, oxidised and the orthophosphate so generated is detected colorimetrically. ... 

---