Hi all,

Another newbie’s question…

Is the sensitivity in APCI (much) lower than in ESI?

I’ve been playing with a brand new DUIS source with our new HPLC MS and the background noise is quite high when I scan m/z 100 to 450.

When I inject a 1uL of a sample of amine (about 0.5mg/ml) on the C18 column (150x4.6 5um) I get close to saturating the detector, yet my ratio signal/noise is only about 7… is that normal when you have an APCI (via the DUIS) ?

I was thinking about it over the weekend and I wonder if it’s because the APCI is the noisy culprit…

I will check my solvents by flowing pure CH3CN and water directly out of the bottles to see if the issue is coming from there.