Gas IRMS Instruments

Precision. Sensitivity. Linearity. Stability.

Highly configurable Thermo Scientific gas isotope ratio mass spectrometers enable you to achieve analytical results across a broad range of research applications with outstanding precision and sensitivity as well as excellent linearity and stability.

Featured gas IRMS instruments
Perform all IRMS applications in a single analyzer

The Thermo Scientific Delta V IRMS combines outstanding sensitivity with excellent linearity and stability to address diverse applications ranging from food and beverage origin and authenticity testing (with EA-IRMS) to soil carbon dating (with GC-IRMS).

Get the highest sensitivity and performance

The Thermo Scientific 253 Plus stable isotope ratio mass spectrometer provides a flexible and open platform for the connection of inlet systems and preparation devices for smallest amounts of sample in IRMS.

Uncover the isotopic anatomy of molecules

Our high resolution isotope ratio mass spectrometers revolutionize the site-specific and clumped-isotope-ratio analysis of molecules, enabling analysts to accurately determine the conditions under which molecules were formed and how they were transported, stored, and degraded.

Discover the benefits of high resolution IRMS
Mass resolving power greater than 18,000

The 253 Ultra HR-IRMS combines a 10 kV electron impact ionization source, a high-mass-resolution double-focusing magnetic-sector mass analyzer, and a variable collector array for a resolving power of 18,000. A high, medium, or low resolution setting for each method can automatically be selected for by using a switchable entrance slit.

Fully integrated workflows

Thermo Scientific's Qtegra intelligent scientific data solution revolutionizes the steps involved in isotope ratio analysis with fully integrated workflows, making high resolution IRMS a routine tool. Qtegra software combines all experiments performed on a specific sample into one "lab book."

Ultimate abundance sensitivity

The variable collector array covers a signal dynamic range greater than 10 orders of magnitude, facilitating the collection of more abundant ion beams in Faraday cups as well as single ion counting of very rare ion species. Weak signals can be analyzed with the axial secondary electron multiplier using the RPQ retardation lens, enabling experiments of high sensitivity.

Modular concept

The 253 Ultra HR-IRMS includes two dual viscous flow inlet systems for handling up to three reference gases together with the sample. This modular dual inlet design allows each dual inlet to be exchanged, avoiding cross contamination of the sample types being analyzed.

High Resolution Gas IRMS Components
Electrostatic detector

The electrostatic sector analyzer (ESA) with a radius of 220mm refocuses the energy dispersion of the ions prior to the magnetic sector.

Entrance slit

The computer-controlled entrance slits can be switched between 5μm and 250μm which allows the selection of low, medium, and high mass resolution.

Magnetic sector

The temperature-controlled, laminated electromagnet has a radius of 230mm. Overall system magnification is a factor of 2, yielding a dispersion of 810mm. Mass range is up to mass 280 at full acceleration voltage, extendable  to 560 at reduced accelerating potential and mass resolving power.

Variable multicollector

On either side of the fixed axial collector there are 4 moveable detector platforms. Each variable detector platform is equipped with a Faraday detector and in addition can carry a compact discrete dynode (CDD) ion counting detector.

10 kV ion source

The gas-tight electron impact ion source with a wide range of adjustable electron energy and variable pumping conductance provides ultra high sensitivity. The ion source preserves clumping and isotopic distribution in the ions because of its low “scrambling” characteristics.


The axial detector channel is a dual mode detector with a Faraday cup and a high sensitivity ion counting detector (SEM). In front of the SEM is a retarding potential quadrupole (RPQ) to reduce the abundance sensitivity for measurement of very small ion beams.

In this eBook, we cover the current state of forensic chemistry and the latest mass spectrometry technologies for staying ahead of your casework. Topics include:

  • Changes in federal and state regulations
  • Drugged driving cases
  • Polydrug use - blood alcohol, marijuana, and cocaine
  • Novel psychoactive substances - cathinones, cannabinoids, fentanyl, and designer drugs

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Featured video

Investigating authenticity and tracing origin with isotope fingerprints

Food and beverage samples have a fingerprint, a unique chemical signature that allows the product to be identified with IRMS.

Featured webinar

In this webinar Dr. Alessandro Casilli, who heads the IRMS Department at the Brazilian Laboratory for Doping Control, discusses how IRMS can be combined with GC-MS for the detection and confirmation of synthetic endogenous anabolic steroids from just one sample injection. He also introduces recent technological advances that potentially eliminate additional HPLC steps via automation.

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