Hello for everyone I come to you to help me find a solution to my problem in the GC MSD I did the tune the first time and everything was good after I injected a sample the filament goes out during the analysis and this last one is interrupted I tried to redo the tune but it does not work normally and an error message is displayed "Tune action stopped: offset at maximum and the peaks are too large"maximum and the peaks are too large" could you guide me to find a solution to this problem please
There may be a number of reasons for this problem.
First, make sure that the ionization energy is set at 70 eV.
Open the Manual tune window, there you can manually change some settings that change the mass peak intensity. Look at the Muliplayer voltage (electron multiplier voltage), you can reduce it at this point. this will reduce the peak intensity. Save this parameter and try to tune again. normally the tune starts with the last saved tune values. You can also reduce the intensity via the lenses built into the ion optics, the system should create a voltage ramp when tuning and then find optimal values. I consider the electron multiplier voltage to be the most likely cause though.
You can also manually tune the entire system to create a tunefile that includes reasonable peak intensities.
Alternatively there are (at least at Agilent Chemstaiton) different tune variants
Autotune, Standard Spectra Tune ect. I usually use the standard spectra tune, because here the correct mass ratios in the spectrum are tuned and so an optimal spectrum for the database is generated.
Try here another tune variant, perhaps the device can be tuned better.
Replace the defective filament at the next opportunity and clean the ion source, since contamination can lead to the EMC voltage is boosted.
(I know the Agilent GC-MSD chemstation, if you use a different software, you should still find a way to manually tune).
Good luck and many greetings
Joachim Horst
if the filament stops working in the middle of an analysis, this probably means it is burnt.
hello thank you for your answer, I forgot to tell you that our GC ms suffered a deterioration previously and we had to change the turbomolecular pump, could that be the cause of this problem so please direct me to a procedure to confirm the presence of the necessary vacuum because i doubt that the vacuum is not sufficient
thank you for all and good evening
Check the voltage supplied to filament. Is there any single voltage reading.
Software application if you find these. If you know increase or decrease the filement voltage and check the single. If signal comes, it is not a problem of filament. If you have filement replace it Some times rarely cone shapes detector also called signal multifier will not dectect the signalls.
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