Nucleotide bases are parts of DNA and RNA. Adenine and guanine are purine-bases; uracil, thymine and cytosine are pyrimidine-bases. In the view of chromatography these compounds are very polar and similar in properties. It is hard to obtain base line separation on traditional C18 as peaks of nucleotide bases co-elute even at low organic concentration. In this application nucleobases are well retained and separated on Primesep 200 mixed-mode column. Compounds are retained by weak reverse phase and weak ion-exchange mechanisms. Method can utilize UV, ELSD, and LC/MS detection.