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Instrument families

OpenARaw's corpus covers two Agilent instrument families, both under the modern AcqData MassHunter directory layout:

Q-TOF​

Quadrupole time-of-flight instruments (models G6540B, G6550A confirmed in the validation corpus). Q-TOF acquisitions can carry profile data, centroid data, or both, and typically run Auto-MS/MS (data-dependent acquisition): MS1 survey scans interleaved with MS2 scans against automatically selected precursors.

  • analyzer on yielded spectra is Analyzer::TOFMS.
  • MS2 spectra carry a real target_mz precursor - see Scan data.
  • MSMassCal.bin (per-scan calibration) and DefaultMassCal.xml (default calibration) convert flight times to m/z. Some bundles have only DefaultMassCal.xml - see MSMassCal.bin.

QQQ​

Triple-quadrupole instruments (model G6410A confirmed in the validation corpus) running targeted MRM (multiple reaction monitoring) acquisitions: a fixed list of precursor/fragment transitions cycled repeatedly through the run.

  • analyzer on yielded spectra is Analyzer::TQMS.
  • Every scan is effectively MS2; there is no isolation-window target_mz in the Q-TOF sense, so precursor identity is carried as precursor_native_id (mrm_channel=<id>) instead - see Scan data.
  • MSMassCal.bin and DefaultMassCal.xml are absent: QQQ m/z is stored directly, with no flight-time calibration.

How the reader tells them apart​

The reader resolves the family from AcqData/Devices.xml's mass spectrometer <Device> entry: <Name>QTOF</Name> maps to Analyzer::TOFMS, <Name>TandemQuadrupole</Name> maps to Analyzer::TQMS - confirmed with zero exceptions across the 330-bundle validation corpus (see docs/format/07-run-metadata.md in the repository). Only when Devices.xml is missing, unparseable, or names a device outside those two known values does it fall back to MSScan.bin's record stride (a 216-, 220- or 284-byte stride indicates Q-TOF; QQQ records use a 186- or 196-byte stride) - see MSScan.bin for the full stride table. If you encounter a .d directory either path misclassifies, please open an issue.