Hello mass spectrometry community! We’re working with a MALDI Synapt in our lab and running into some challenges with high-mass calibration. We’ve been using PEG standards (1000, 2000, 4000) for calibration with the MALDI source, and while the calibration from 700 to 2800 m/z seems solid, we’re seeing a significant discrepancy at higher mass ranges, specifically with PEG 4000. Our quadrupole is 8k, and we’re wondering if adjusting the EDC delay (either under or above 4000) might help improve our spectrum quality and mass accuracy in this range. Has anyone encountered a similar issue, or have any advice on optimizing for high-mass calibration? Any tips on adjusting EDC delay for more accurate high-m/z measurements would be greatly appreciated. Thanks in advance for your insights!