To run a small analytical cycle to ensure the oligonucleotide is clean, a small sample is diluted to a concentration around 5 ug/ul with diH2O with a flow rate of 1.0 ml/min. For analytical scale, the Agilent PLRP-S 8 um, 4.6 x 250 mm column (Agilent, PL1512-5800) is used. If purification of the full oligonucleotide is needed, the sample is diluted to a concentration of 25 ug/ul with an injection volume of 100 ul and purified using the semi-prep column Agilent PLRP-S 8 um, 7.5 x 300 mm (Agilent, PL1112-6800) at a flow rate of 2.4 ml/min. A comparison of the flow rate, injection volume, and oligonucleotide concentration used for both columns is show in Table .