Quantitative determination of nucleosides and their phosphate esters--1. The acidic nucleosides, 3-deazauridine and 6-azauridine.

A relatively rapid, high-resolution chromatographic procedure, using mini-columns of DEAE cellulose equilibrated with 10 mM sodium phosphate, pH 6.0, is described in sufficient detail to permit ready replication. This initial paper demonstrates the quantitative separation, using suction, of the acidic nucleosides, 3-deazauridine and 6-azauridine, from their phosphorylated derivatives. The chemically stable, tritium-labeled nucleosides are eluted from the mini-columns (capacity approximately equal to 1.8 ml) with 10 mM sodium phosphate, pH 6.0; subsequently, the nucleotides are eluted completely with 0.5 M HCl/0.5 M NaCl. Quantitation is based on liquid scintillation counting of aliquots of the eluates.