Expanded m/z region showing the 17+ charge state in the ESI FT-ICR mass spectra of horse heart myoglobin. (A) Iodinated Mb (1 μM) in water/methanol (1/1, v/v, 1% acetic acid), electrochemical iodination with cyclic pulsed potentials (2.5 s at 0.4 V vs SCE and 5 s at 0.0 V vs SCE, 240 cycles,), (B) Iodinated Mb (1 μM) in water/methanol (1/1, v/v, 1% acetic acid), electrochemical iodination with cyclic pulsed potentials (2.5 s at 0.4 V vs SCE and 5 s at 0.0 V vs SCE, 420 cycles).