quadrupoleOrbitrap

QuadrupoleOrbitrap is a hybrid mass spectrometry configuration that combines a quadrupole mass filter with an Orbitrap high-resolution mass analyzer. The quadrupole provides selective transmission and isolation of a precursor ion by its m/z, while the Orbitrap furnishes high-resolution, high-accuracy mass measurements and often enables MS/MS applications.

Operation involves ions generated by electrospray ionization or other sources entering the instrument. The quadrupole isolates the precursor ion within a defined m/z window. The isolated ions are then directed into the Orbitrap, where their oscillations are detected to determine m/z with high resolution and accuracy. Fragmentation for tandem MS is typically performed in a collision cell (using HCD or CID), and the resulting product ions are analyzed in the Orbitrap. This setup supports data-dependent acquisition as well as targeted approaches such as parallel reaction monitoring.

Performance characteristics include resolving power that can range from tens of thousands to well over 100,000, depending on settings, and mass accuracy usually in the low parts-per-million after calibration. The quadrupole isolation enables precise precursor selection, facilitating targeted quantification and identification in complex mixtures, as well as high-quality MS/MS spectra for confident compound characterization.

Applications span proteomics, metabolomics, and lipidomics, where the combination of targeted precursor selection and high-resolution measurement supports both discovery and quantitative workflows. The technology enables high-confidence peptide and metabolite identifications, accurate mass measurements, and robust quantitation in a single instrument.

Variants of this architecture are marketed by multiple vendors, with the Thermo Fisher Q Exactive family being a well-known example.