Tailing peaks are a nuisance in HPLC. And they happen all the time.
The common misconception about peak tailing is that it is caused by sample overload. No, it’s not.
Most of the time, peak tailing is caused by a bad column.
Here’s why peaks tail, and what to do about it:
1) Active silanol sites on column – Use 0.1 % triethylamine in mobile phase. Or get a better column, with a higher carbon load.
2 ) Sample ionisation – Adjust pH to suppress ionisation.
3) K’ too large – Increase mobile phase strength.
4) Insufficient end-capping – Change column.
5) Hidden peak on tail – Change detection wavelength and/or change mobile phase strength.
If you have persistent peak tailing, you have a bad column. You have no choice but to change it.
Cheers … SKS