Hello!I had a very noisy signal at the tune window in MS scan (e6-5, with a huge m/z 59 of intensity 4.0e7) with fluidics valve in waste. Intellistart instrument calibration yielded abnormal values, probably because of contamination. After thoroughly cleaning the source (ion block, cone, etc.; they didn´t seem so dirty), background signal was succesfully reduced to e3 (MS scan and valve in waste). But after infusing calibration solution (ICe-INa in MeOH) signal rise again and remain constant in e6 after hours in waste position (see below). I don´t think calibration solution is the problem, infusion lasted no mare than 10 minutes. Furthermore, signal does not decrease after switching fluidics to waste. Thank you!