Ion exchange purification of mRNA

A method for purifying a messenger ribonucleic acid transcript from a sample comprising the messenger ribonucleic acid transcript of 300 to 10,000 nucleotides in length and impurities, comprising the steps of:

• (a) a contacting step comprising contacting the sample to an ion exchange sorbent comprising a positively-charged functional group linked to solid phase media, wherein the sample comprises an aqueous-based solution and the messenger ribonucleic acid transcript binds the positively-charged functional group of the ion exchange sorbent while at least a portion of the impurities in the sample pass through the ion exchange sorbent;
• (b) a washing step comprising washing the ion exchange sorbent with a buffer comprising about 150 mM sodium chloride to cause at least a portion of the remaining impurities to pass through the ion exchange sorbent;
• and
• (c) an eluting step comprising eluting from the ion exchange sorbent with a buffer comprising about 2 M sodium chloride a purified sample comprising the messenger ribonucleic acid transcript,
• wherein the contacting step, the washing step, and the eluting step are performed at a temperature of about 65 degrees Celsius, and
• at least 80% of the messenger ribonucleic acid transcript in the sample is recovered in the purified sample.