I Have Split/Broad Peaks and Shorter Retention Times for PP-ODS Columns
Purpose
The recommended way to wash a PP-ODS column when a simple water/methanol wash does not fix the peak issue is outlined in this article.
Solution
Problem: Broadened or split peaks were observed on chromatogram of PP-ODS2. Dopamine seemed OK, but if magnified the peak was broadened as well. The retention times were also slightly earlier. 100% methanol wash in the reverse direction did not correct the problem.
Solution: To correct, the PP-ODS column needs to be washed as follows.
1. 30 min water in the reverse direction at half the normal flow rate.
2. 1 hr with 0.1% phosphoric acid in 100% acetonitrile in the reverse direction
3. 30 min water in the normal direction
4. Run analytical mobile phase overnight to lower the BGC.
5. Re-check the separation.
We assume the contamination at the column top could not removed by methanol wash but could with acetonitrile.