We are facing stability problems on our ICP-MS 7900. We lose up to 10% of the signal when analysing twice the same sample at the beginning and at the end of our samples sequence, no matter which element is analyzed, with or without gas. RSD are low, signal is ok for blank.
There are days where it works perfectly fine and other not at all.
We tried to perform cleaning, change tubes, change cones but nothing is working to improve our results. We usually do not use any ISTD but we tried once with and it didn't help as the instability is not constant depending on element, time ....
Is there someone facing similar instability issue ?
Thank you very much for your help !