Chromatography Forum

I am having a problem with our IC method, specifically nitrate. All other QC's pass but nitrate is consistently ~60% of what it is supposed to be. We are running a waters 2695 with Waters 432 suppressed conductivity detector, and a dionex ionpac as14 column. The last 6 peaks are the ones of interest, Standard 3 should be close to the same size as QC, and they are for all peaks except nitrate. I have tried different sets of standards, and different sets of QC's multiple times and I keep getting similar results. Any input?

Hi Mritari,

What are you using as a suppressor--perhaps the SeQuant one? Could the suppressor itself be fouled with some component(s) that are present in the QC matrix but not the standard? Or from something from within the samples...such as iron or manganese?

Please, see what you think, and best wishes.