What are reasonable FTICR technical capabilities to expect for peptides/proteins?
We routinely achieve ~10-20 ppm mass accuracy for peptides of m/z ~1000-2000 with external mass calibration, and 1 ppm or better with internal calibration. Generally speaking, mass resolving power (and mass accuracy) decrease as 1/(m/z) (i.e., mass accuracy is worse at higher m/z). There is a brief discussion of mass resolving power, mass resolution, and mass accuracy in: Marshall, A. G.; Hendrickson, C. L.; Shi. S. D.-H. (2002) “Scaling MS Plateaus with FTICR MS,” Anal. Chem. 74, 252A-259A.
