OPTIMIZATION OF CONDITIONS FOR ION-PAIR H PLC OF OLIGONUCLEOTIDES

Regularities of ion-pair HPLC of oligonucleotides were studied. An alg orithm was suggested for the calculation of the acetonitrile gradient providing proportionality between the number of nucleotide residues an d the retention time of the oligonucleotide (t(R)) (equidistant separa tion of oligonucleotides). The algorithm is based on extrapolation of the results of separation of a test mixture of five oligonucleotides v arying in length from 10 to 30 units. It was shown that the logarithmi c gradient of acetonitrile C-0 + mln(t) leads to the equidistant separ ation of oligonucleotides. The separation is characterized by two meas ured parameters: the retention time step and the extent of equidistant ness. A functional dependence of the measured parameters on two varyin g parameters of the logarithmic function (C-0 and m) was established e xperimentally. A method for calculating the, expected retention time o f an oligonucleotide from its nucleoside composition was suggested.