[asorocha]

I can't have consistent results when I work with the iron lamp. I use three standards (3, 6, 9 mg/L) and I was hopping that I had three ascendant signals... that isn't happening.
I tried new solutions, different concentrations, different lamp preheating periods, moving lamp to another position, nothing seems to work... I even change the lamp current near maximum, nothing!
Any idea what's the solution for my problem?

[Corribus]

Have you ruled out contaminations? Iron is everywhere.

[asorocha]

yes. I have rinsed all my material with acidified (HNO3) desionized water ...