Fourier transform ion cyclotron resonance spectroscopy (Reprinted from Chemical Physics Letters, vol 25, pg 282-283, 1974)

An ion cyclotron resonance (ICR) absorption spectrum has been obtained by exciting an ICR spectral segment with a fixed-frequency electric field pulse, followed by broad-band detection, digitization of the (time-domain) transient response, and digital Fourier transformation to produce the (frequency-domain) absorption spectrum. For a given signal-to-noise ratio and resolution, the FT-ICR method generates a spectrum in a time which is two orders of magnitude shorter than that required in conventional slow-sweep ICR detection. in the present example, a signal-to-noise ratio of 8:1 and a mass resolution of about 0.005 amu For CH4+ (from CH4 at a pressure of 8 x 10(-7) torr) have been achieved, using a single data acquisition period oi 25.6 msec.