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. Author manuscript; available in PMC: 2011 Jul 1.
Published in final edited form as: J Am Soc Mass Spectrom. 2010 Mar 31;21(7):1218–1222. doi: 10.1016/j.jasms.2010.03.033

Figure 2.

Figure 2

The relationship of magnetic field and accuracy. a) Arithmetic mean of absolute mass measurement error using Bruker FT-ICR mass spectrometers (left panel). Internal calibration of NaFA and a complex mixture of nine proteins and peptides were compared to their theoretical values. Accuracy improves ~2nd order in magnetic field for NaFA sample and ~3rd order for complex protein and peptide mixture. Extrapolation to 15 T predicts 22 ppb mass error. The curves are an average of 3 spectra and shown error bars represent 2 standard deviations each direction. Error bars for small molecule data at 7 T and 9.4 T were too small for Excel to draw. b) Magnetic field’s effect on accuracy in literature. Experimental average accuracies from 24 references were plotted with respect to the magnetic field used. Values are from analyses that used different analytes, instruments, users, etc. A detailed table of the references is given as supplementary table.