We currently have a QTOF 6545A in our laboratory and are having issues with the reference nebulizer (side position) in our Jet Stream Technology ion source. We are unable to see any signal from Calibrant A, the reference mixture (HP0921 and purine). The nebulizer is bubbly and spitty which indicated the nebulizer needle needed to be changed. I've done so and am still having issues. I have tried the following things to see if I can isolate the problem:
Move the reference mixture to the Calibrant B position. When moved, we see the signal which indicates that our solution is not bad (we just purchased and made new mixtures for this very purpose). Also when I place the calibration/tuning mixture into the Calibrant A position, we no longer see a signal for this mixture, indicating something is wrong with the reference flow line/nebulizer. I placed the calibrants back in their original positions and next switched the flow lines so the Calibrant B (tuning solution) went to the reference nebulizer and saw no signal, but saw a Calibrant A, now going to the regular top position nebulizer, signal which said to me at least it was the reference nebulizer. However, my last step was to have everything set up the normal way except switch the actual nebulizers. When I did this, the nebulizer in the reference position did not produce a signal and was bubbly/spitty like the original nebulizer in that position was doing, and the nebulizer in question now placed in the top position was working fine and produced a signal. It ultimately has something to do with the reference (side) position.
The only thing I can think of is insufficient gas flow, but if anyone has had issues like this before or knows of something else that has been overlooked we would greatly appreciate it!