Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry, can reach a resolving power of 10,000,000 and more; can reach a mass accuracy of 0.5 - 1 ppm or better; can have 1-5% accurate isotopic abundances; can cost several million dollars; superconducting magnets can have a field strength of up to 25 Tesla. A nice photo of a 14.5 Tesla magnet FT-MS can be seen here. Check our LTQ-FT here.

Title Multidimensional GC Fourier Transform Ion Cyclotron Resonance Mass
Spectrometry: Resolving Complex Mixtures
Source ASMS 04
Touradj Solouki; Jan. E. Szulejko; Zhaohui Luo
Department of Chemistry, University of Maine, Orono, U.S.A.
Short Review

GC-FT/MS is a pretty new (1980) and exciting technique, which has great potentials - electron impact (EI) and chemical ionization (CI) can be employed - high resolving power 250,000 @ m/z= 250 - and high mass accuracy. However the technique suffers from interface problems, hence connecting the extremely low vacuum FT-MS and the high-flow GC together. One possible solution is cryofocusing as mentioned in the abstract. Furthermore scan speed may be a problem because FT analyzers need longer trapping time with increasing resolving power. See also [Google Scholar] collection on GC-FT-ICR-MS.

Title Counting individual sulfur atoms in a protein by ultrahighresolution Fourier transform ion cyclotron resonance mass spectrometry: Experimental resolution of
isotopic fine structure in proteins
Source PNAS 1998;95;11532-11537
Stone D.-H. Shi, Christopher L. Hendrickson, and Alan G. Marshall
DOI doi:10.1073/pnas.95.20.11532
Short Review

This paper gives an excellent overview about state-of-the-art measurements which can be achieved by FT-MS. Such extreme results are still far away from commercial and affordable implementations (This written in 2007, the article is from 1998). The paper also stated the important fact: "Although the present data can, with appropriate internal mass calibration, yield ultrahigh mass accuracy, the main point here is that high mass accuracy is not required for identification and quantitation of the number of atoms of a given element in a molecule. Rather, one requires ultrahigh mass resolution (to distinguish different elemental compositions) and accurate ion relative abundances
(here, to within a few percent)."

Unfortunately even FT-MS is not capable of solving the manifold problems during structure elucidation of small molecules (<2000 Da). The impact on protein/peptide research, glycoside research, posttranslational modifications; hence targeted approaches seems to be much higher.


Milestones in Fourier transform ion cyclotron resonance mass spectrometry technique development

Source International Journal of Mass Spectrometry 200 (2000) 331-356
Alan G. Marshall
Short Review

A very comprehensive review for all people involved in mass spectrometry and FT-MS. More than 269 references, more than 104 references by Alan G. Marshall himself; an indicator of his important contributions to the field of FT-ICR-MS. A very useful table is Table 9 containing the world records and milestones. However some of the values must be read carefully because the original publications contain constrains like only certain elements counts or certain elements involved, which are not mentioned here.

FT-ICR world records for mass analysis

Mass accuracy/elemental composition
1. Highest mass accuracy over wide mass range: ±0.5 ppm from 90-300 Da; 61 ppm from 250-1000 Da
2. Highest mass for unique elemental composition: 895 Da
3. Highest mass precision: ±0.000 000 09 Da @ 20 Da

Mass resolving power, m/dm 50%
1. Highest resolving power for ions of a single m/z: 200,000,000
2. Highest resolving power for ions of multiple m/z at high mass: 8,000,000 @ 8.6 kDa

Mass resolution (separation of closely-spaced masses)
1. Highest resolution of two molecules: 0.00045 Da @ 906 Da
2. Highest direct-mode (broadband resolution): 0.0034 Da @ 1326 Da
3. Highest mass for resolved isotopic fine structure: 15.8 kDa
4. Highest mass for unit mass resolution: 112 kDa

Most complex mixture analyzed from a single mass spectrum
1. ~5,000 elemental compositions
2. 583 peptides, resolved to better than 1 Dam
Highest mass for a chemically pure molecule: 100,000,000 Da

Tandem mass spectrometry
1. Highest mass resolving power for MS1: 20,000
2. Highest mass resolving power for MS2: Similar to FT-ICR without MS

Title High-Resolution Mass Spectrometers
Source Annual Review of Analytical Chemistry. Volume 1, Page 579-599, Jul 2008
Short Review

This colorful review discusses the concepts of mass resolution and mass-resolving power together with mass accuracy and mass calibration issues for TOF-MS, FT-ICR-MS and Orbitraps. The term "scan speed" doesn't occur but duty cycle time is explained. Unfortunately no discussion of the MS/MS isolation widths is included. This is important for ion selection on hybrid mass analyzers. But High Mass Accuracy: What It Can and Cannot Provide and the need for higher mass resolution are explained.

Short Review