After ions enter the electrostatic field of the Orbitrap, they undergo axial oscillation around the central electrode and are trapped by the outer ring electrode, forming a stable orbit. Ions of different m/z have different oscillation frequencies; the detected image current is Fourier-transformed to obtain a frequency spectrum, which is then mapped to a mass spectrum.
Because separation relies on frequency rather than flight distance, Orbitrap achieves high resolution in a compact structure; its mass accuracy can reach ppm level, helping to accurately assign molecular species in complex tissue spectra.
Orbitrap mostly serves as the high-resolution detection end of imaging sources (MALDI, LDPI, DPI, DESI), providing sufficient mass accuracy to distinguish molecules with similar m/z (such as isotopes, adduct peaks), especially valuable for lipid and metabolite annotation.
Compared with TOF, Orbitrap excels in high mass accuracy, but imaging acquisition speed is affected by the ion injection cycle; in practice, one often chooses between the two according to resolution and speed needs, or combines MS/MS for structural confirmation.
Using Orbitrap for imaging requires point-by-point acquisition and stitching into ion images; its high-resolution spectral data volume is large, relying on dedicated software (SCiLS Lab, MetaboScape) for visualization and quantification, often exchanged in standard formats such as imzML.
For users requiring ambient matrix-free imaging, Neo-Source LDPI/DPI can be externally added to an Orbitrap with an ambient interface, forming a high-resolution matrix-free imaging solution.
The advantage of Orbitrap is high resolution and mass accuracy, suitable for imaging requiring precise molecular assignment; the limitations are pixel throughput per unit time and acquisition cost, and scanning speed decreases at very high resolution. For rapid screening or extremely high-resolution needs, TOF or TOF-SIMS can be compared.
Comprehensive selection should integrate analyte, resolution, throughput, and budget; for building a new matrix-free ambient imaging line, LDPI/DPI + Orbitrap is one of the high-resolution routes.
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).