A constant-fraction discrimination (CFD) system has been combined with a boxcar integrator for detection in inductively coupled plasma/time-of-flight mass spectrometry. The discriminator provides gating logic for the boxcar integrator when an incoming ion signal occurs, but discriminates against electronic or background noise of lower amplitude. As a result, the combination can effectively reject noise and accumulate analyte signal, rather than relying on an averaging process to reduce noise levels. The signal-to-noise ratio is therefore enhanced in this operation compared with the conventional boxcar method. The dynamic range of the detection system is at least five orders of magnitude.
SinC. H. and LeeE. D, and LeeM. L., Anal. Chem.63, 2897 (1991).
2.
MyersD. P.LiG. and YangP, and HieftjeG. M., J. Am. Soc. Mass Spectrom.5, 1008 (1994).
3.
FalkH., J. Anal. Atom. Spectrom.7, 255 (1992).
4.
MaC.MichealS. M.ChienM. and ZhuJ, and LubmanD. M., Rev. Sci. Instrum.63, 139 (1992).
5.
HollandJ. F.NewcombeB.TecklenburgR. E.Jr.DavenportM.AllisonJ. and WatsonJ. T, and EnkeC. G., Rev. Sci. Instrum.62, 69 (1991).
6.
FerronJ. R., Rev. Sci. Instrum.63, 5464 (1992).
7.
ArtaaevV. B.BurrillP. H.McNittK. L.SchmitzD. A. and EnkeC. G, and HollandJ. F., “High-Speed GC/MS Analysis of Complex Mixtures using Time-of-Flight Mass Spectrometry with Time-Array Detection,” poster TP186 presented at the 42nd ASMS Conference on Mass Spectrometry and Allied Topics, Chicago, Illinois (1994).
8.
SmithB. K. and DelaneyP. A, and PasslerM. A., Rev. Sci. Instrum.59, 2079 (1988).
9.
Instruction manual for TC 454 quad constant fraction discriminator (Oxford Instrument Inc., Oak Ridge, Tennessee, 1987).
