Column problem for acid nitrilotriacetic

[mcalvo]

We are analyzing the content of acid nitrilotriacetic in EDTA disodium according to the USP monograph and after few injections (20-30 injections) the tailing increase for the peaks of acid nitrilotriacetic and EDTA and the theoretical number plates decrease.
The column is a C8, the method is isocratic, the mobile phase is a mixture of a solution of tetrabutylammonium hydroxide adjusted at pH 7.5 and MeOH (91 : 9) and the diluent is a solution of 10 mg/ml of cupric nitrate.
How can I regenerate the column? Is there some washing method to prevent the degradation of the column?

[dap]

Hello.
You could try to reverse flow through the column and flush it. Also column guards should enlarge column life time.