On the high‐resolution mass analysis of the product ions in tandem time‐of‐flight (TOF/TOF) mass spectrometers using a time‐dependent re‐acceleration technique

Abstract

The time-dependent reacceleration of product ions produced as a result of dissociation of a single precursor ion in a tandem time-of-flight mass spectrometer is considered for the first time. Analytical expressions for the shapes of electric pulses bringing all the kinetic energies of the product ions to the same value are derived for two cases: forward acceleration mode and deceleration, followed by re-acceleration in the reversed direction (reversed mode). Secondary time-of-flight focusing resulting from the re-acceleration in the reversed mode is shown to be mass-dependent and, when averaged over a wide mass range, the focusing is tight enough to provide mass resolution exceeding 10,000. After time-dependent re-acceleration, additional compression of the ion packet width leading to better mass resolution can be obtained by decelerating the ions in a constant field.

Booster-microchannel plate (BMCP) detector for signal amplification in MALDI-TOF mass spectrometry for ions beyondm/z50 000

“…On the other hand, we could identify two well-known-but opposite-ion optical mechanisms that could have led to the observed signal amplification: first, the used electrode configuration may cause-aside from the intended ion acceleration-a certain spatial focusing of the ion beam, as it was noticed for other electrode configurations beforehand. 11,15,26,32 Second, the negative electrode booster potential may lead to an ion beam divergency. Thus, the positively charged ion cloud would cover a larger area of the active MCP surface, which may be favorable with regard to the relatively long dead time (millisecond range) of the single channels.…”

In pursuit of resolution in time‐of‐flight mass spectrometry: A historical perspective

“…Ioanoviciu (1994Ioanoviciu ( , 2000 presented general theoretical analyses. Theoretical calculations for ion mirrors with time-dependent electric fields for the special case of matrix-assisted laser desorption/ionisation (MALDI) have been carried out by Moskovets and colleagues (Moskovets, 1993;Kurnosenko & Moskovets, 2010). Stein (1994) and Short and Todd (1994) described improved time-focusing and energy compensation.…”

Proteomics of <i>E.coli Nissle 1917</i> in Responce to<i> Cocos nucifera</i> sap and Wine

“…To achieve acceptable mass resolution for PSD ions which masses typically distributed over broad mass range, these ions are accelerated to energies substantially (Kurnosenko et al, 2010) exceeding the initial energy of precursor ions.…”