LimsPulse
Chromatography

Gas Chromatography–Mass Spectrometry (GC-MS)

Couples a gas chromatograph to a mass spectrometer so each volatile compound is separated and then identified from its fragmentation pattern. Used for unknown volatile impurities, nitrosamines, residual solvent confirmation and extractables.

  • Pharmaceutical
  • Environmental
  • Forensic and toxicology
  • Food & flavour
  • Petrochemical
  • Packaging
Photo of a Gas Chromatography–Mass Spectrometry (GC-MS)
Photo: Polimerek, CC BY-SA 4.0 (cropped), via Wikimedia Commons
Follow your site SOP
This is a typical operating sequence for learning. Your instrument model and approved SOP take precedence.
STAGE 1

Before you start

  1. 1Check the carrier gas supply and that gas purifiers / traps are in date.
  2. 2Check vacuum readings and that the last tune report passed.
  3. 3Replace the inlet septum and liner if due, and check the column is correctly installed into the transfer line.
  • Never open the MS to air while the source and turbo pump are hot and running; always follow the venting procedure.
STAGE 2

Start-up

  1. 1Allow the vacuum to stabilise after any venting (often several hours).
  2. 2Run the autotune (or a tune check) and review the tune report: masses, peak widths, abundances, air / water levels.
  3. 3Bake out or condition the column if the method requires.
  4. 4Run a solvent blank to check the baseline and column bleed.
  • High m/z 28 and 32 in the tune report show an air leak; fix it before running samples.
STAGE 3

Running samples

  1. 1Set a solvent delay so the filament is off while the solvent peak passes.
  2. 2Run blank, standards, system suitability and samples as per the sequence.
  3. 3For unknowns, acquire in full scan and search the library; for trace quantitation, use SIM or MRM.
  4. 4Confirm identity with retention time and, where possible, a reference standard.
  • A library hit is a suggestion, not proof; report identity only as confirmed by the method or a standard.
STAGE 4

Shutdown

  1. 1Cool the oven and inlet; keep carrier gas flowing through the column.
  2. 2Leave the MS under vacuum in standby, or follow the venting procedure for maintenance.
  3. 3Complete the usage log including tune and vacuum data.
In LimsPulse · Calibration Management

Keep every GC-MS in control: usage logs, calibration and maintenance schedules, and automatic blocking of overdue instruments.

See how