Chromatography Forum

Dear All,

During the investigation, we identified the peak showing in Water (Diluent) Injection in HPLC with method having @210nm. Its keep increasing over the time. Does anyone seen this kind of pattern. Your suggestions will be helpful.

Is this a gradient method? If yes, does the peak appear when running a no-injection blank?

Yes, its gradient method. I cannot see the peak in gradient(no injection). The peak only appeared in blank (water) & subsequent injections. When we inject the same blank vial (without cap) multiple injections, the unknown impurity increasing. I dont understand the phenomenon that how can pure water can give the unkwon peak at same retention time?

I would guess that something is being absorbed into the sample after it is prepared. Maybe something volatile in the lab atmosphere?