Introduction

Since base pairing is specific and reversible, it recommends itself as the basis of a form of affinity chromatography suitable for the separation and isolation of nucleic acids and their fragments. This is accomplished in practice by immobilizing defined nucleic acids, polynucleotides, oligonucleotides, or nucleic acid residues on a stationary phase. The requirements of a suitable system for template chromatography are dictated by the moiety to be purified, the coupling of ligand to matrix, and the working milieu. For many research purposes details of molecular parameters may be vital: knowledge and reproducibility of coupling modes, matrix characteristics, and ligand-matrix-medium interactions then assume paramount importance. For large-scale production in particular, mechanical stability, rapid flow rate, resistance to microbial attack, and reuse are important factors. This may be achieved either by coupling the ligand to one end of an “arm,” the other end of which is subsequently attached to the carrier, or by coupling it to an arm already modifying the matrix.