Usually expressed as pixels/second or the total time to complete a field of view. It is jointly determined by single-pixel dwell time (laser/ion pulses x repetition frequency) and scanning-mechanism motion speed: longer dwell gives more stable signal but longer total time.
For point-by-point imaging, faster scan speed is not always better; a balance between sufficient signal and acceptable duration is needed, especially for low-abundance molecules requiring longer dwell.
Source level: laser/ion-beam repetition frequency, pulse energy; detection level: analyzer acquisition speed (TOF is fast, Orbitrap is limited by injection cycle); mechanical level: stage speed, acceleration/deceleration, and positioning accuracy; sample level: required signal-to-noise determines dwell.
The per-point throughput of high-resolution analyzers (such as Orbitrap) is usually lower than TOF, which is why Q-TOF is often chosen for rapid imaging; ambient sources (LDPI/DPI/DESI) scan speed is also affected by spray/photochemical stability.
The larger the field of view and the higher the resolution (more pixels), the total sampling volume grows exponentially. For example, halving the step size makes pixel count fourfold, and total time roughly fourfold; unless scan speed is raised in sync. Thus resolution gains often come with duration cost.
Engineering often uses a two-stage strategy of low-resolution fast screening first, then high-resolution targeting to control total time, balancing throughput and detail.
Optimization directions include raising source repetition frequency, using faster analyzers (TOF/Q-TOF), parallel multi-pixel sampling, and graded dwell by molecular importance. For large-cohort studies, scan speed directly affects affordable sample size.
Selection should combine field of view, resolution, and acceptable per-sample duration; for matrix-free ambient sources (LDPI/DPI), combine short preparation with reasonable scan speed to improve overall efficiency.
To obtain detailed specifications, compatible models, or a quotation for the MSI LDPI / DPI full series imaging ion sources, visit the Neo-Source official website, or contact the official team for compatibility advice tailored to your mass spectrometer (Agilent / SCIEX / Thermo and other mainstream MS).