Another pronounced difference between the resins was observed in the inverted elution of ss- and dsDNA, where ssDNA eluted at 2.88 M NaCl on Capto Adhere, while on Capto Q ImpRes ssDNA eluted already at 1.47 M NaCl. This recognition was not observed for Capto Adhere. Capto Q ImpRes provided a recognition for guanylate bases when samples of deoxynucleotides or poly(dG) were examined. All deoxynucleotides and DNAs tested bound strongly to the chromatographic materials and could be eluted by a linear gradient of increasing NaCl concentration. These variations in biophysical properties have been utilized for comparative separations on these two resins. The intrinsic differences between single- and double-stranded DNAs are related to charge, hydrophobicity, size and three-dimensional structure. Capto Adhere carries a multimodal ligand which combines strong anion with aromatic recognition, while Capto Q ImpRes is a strong anion exchanger with a chemically similar ligand, but without a phenyl group. The differences in chromatographic behaviour of individual deoxynucleotides as well as small single-stranded and double-stranded DNA molecules have been examined for two resins from the Capto family: Capto Adhere and Capto Q ImpRes.
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