PPG manual tuning problem

[HaruYap]

Hi there. I am having a problem with PPG manual tuning for my ABI Qtrap 4000. It seems that I have difficulty getting the appropriate peaks; either the senstivity is too low, or the peaks drifting and are quite spiky. The peak width is also very small; making the peaks very sharp and after running MCA for 10cycles, the peaks will obviously be co-eluted; forming one huge broad peak. This is especially for peaks at mass 906.

FYI, I have tried preparing new batches of standards but the problems still persist. Have also tried to play around with the system parameters and also tried the default settings and such but to no avail.

May I know what seems to be the problem? And any remedies for such problems? Its getting into my head now and a solution would be great and ideal~

[HaruYap]

Hi there. Just wanna make a post since others might have encountered the same problem. Have sort the problem out and what we did was the basic elimination of contaminations. Turned out that the water being used for standard preparations were not of ultra pure water quality. I mean, the water was from the supposedly UPW water system but I guess the carbon filter in the system might have failed. Also, we changed and trimmed the PEEK tubing and also clean the ion source; this solved the problem I'm having with the tuning peaks of PPG.

Hope the info helps anyone who face the same problem!!!