Chromatography Forum

Hello! I have a problem with signal loss on MS Shimadzu. Lately I have had lower peaks until one day the signal was completely lost between two analyses. I cleaned the MS, did a tuning, and changed the capillaries leading from the LC and ESI capillary. After injecting the standard without the column, the signal is still lower than I would expect and after injecting with the column, all I see is noise.
Any idea what this could be, please?

The standards, MF are new, the column is also almost new and works well, cleaning and tuning was done as always.

Do you have a strong signal when tuning?

If so then it would point more towards the HPLC side of things, if tuning signal is low then I would focus on the MS side.

Possible bad electron multiplier? (or does Shimadzu use the PMT, I remember one manufacturer does but can remember which.)