PNNL

Abstract

Distance-of-flight mass spectrometry (DOFMS) offers the advantages of physical separation of ions, array-detection of ions, focusing of initial ion energy, great simplicity, and truly unlimited mass range. DOFMS instrumentation is similar to that of time-of-flight mass spectrometry (TOFMS) and shares its ion source versatility, batch analysis, and rapid spectral generation rate. With constant-momentum ion acceleration and an ion mirror, there is a time at which ions of all m/z values are energy-focused at their particular distance along the flight path. A pulsed field orthogonal to the flight path drives the ions to reach the detector array at this specific time. Results from a 0.31-m proof-of-principle instrument verify the theoretically predicted energy focus and demonstrate how the range of m/z values impinging on the detector array can be readily changed. DOFMS can potentially be combined sequentially with TOFMS to enable simultaneous scanless MS/MS.