LCMS peaks at hight temp

[rrugama12]

I have been running a standard of retinal oxime on my LCMS (TSQ Quantum Access Max) that had been working with a method that had the capillary temperature set to 325 C. As of a couple weeks ago that standard was not producing the results I was expecting/ not picking up any signal from injections. I later found that the signal would appear when I used the same method I had been using, but with the capillary set to a 50 C. I was wondering if I could get some feedback as to why I am observing this in my results?

[JMB]

Is this the temp of the heated capillary of an APCI source??

Your results suggest that your analyte is somewhat thermally unstable.

What m/z signals, if any, do you see at 325 C?

Regards

[rrugama12]

Thanks for the response. I was logged out for a while, but found a solution for that problem. The peaks came back just by thorough cleanings and re-calibrating the instrument.

I am having another problem now. I am running my standard and will get a signal decrease after about 10 injections. I don't believe this issue to be charging because we cleaned the instrument from the ion optic cone to the Q01. Any thoughts?