6545 QTOF with noise at low mass and bad response at high mass

Hello, hoping the collective Agilent community wisdom has ideas about what to try next. We have a 6545 QTOF that has been giving us the response in the attached photo. We have tried everything we can think of to get back to what a good tune solution should look like including:

- solution made with a newly purchased bottle of ESI-L, new ampule of biopolymer mix, newly opened bottles of Fisher Optima LC-MS acetonitrile and Fisher Optima LC-MS water

- flushed tubing between the bottle and the nebulizer with acetonitrile/water, flushed nebulizer and cleaned and inspected nebulizer and the spray looks good. We see the same spectrum with the tune solution coming from the top nebulizer on the jet stream source and the reference nebulizer

- vacuum looks normal, ion transfer capillary has been freshly cleaned, source has been freshly cleaned

And now we are stumped. We would be grateful for any ideas.

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  • Ultimately this is what we ended up doing. A field service engineer cleaned the ion optics which helped but did not resolve the situation. We also found PEG contamination in a bottle of *brand new* ESI-L tune mix. I had two bottles from that lot and this issue of PEG contamination in the tune mix complicated my efforts to troubleshoot the problem ourselves. We have notified Agilent of the contamination problem and lot number.

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