Extraction of adenosine nucleotides by a long-chain quaternary ammonium salt

Liquid-liquid extraction of adenosine nucleotides was performed by using a long-chain quaternary ammonium salt as the extractant. The addition of a small amount of alcohol facilitated the solubilization of long-chain quaternary ammonium salts into hydrophobic organic solvents such as hexane and isooctane. Therefore, a solvent extraction system for nucleotides was obtained, where the use of chlorinated organic solvents was avoided. In the forward extraction, the pH value in the feed aqueous solution was the key factor to achieve quantitative extraction. Adenosine monophosphate (AMP) can be separated from di- and tri- phosphate (ADP and ATP) by adjusting the salt concentration. However, adenosine that has no phosphoric group was not extracted at all. Based on the results, the main driving force for the extraction was found to be the electrostatic interaction between the phosphoric part of nucleotides and the cationic part of the extractant. In the stripping, the salt species and its concentration were crucial parameters for the effective recovery of nucleotides from the organic phase. Under the optimum conditions, 98% nucleotides were recovered to a fresh aqueous solution.