Stable Isotope Laboratory

New Mexico Tech Stable Isotope Lab



Welcome to the New Mexico Tech Stable Isotope Lab Webpage. The lab is equipped with a Thermo Finnigan Delta Plus XP mass spectrometer and several peripheral units. Scroll down to read about the capabilities of the Stable Isotope Lab and the classes offered at Tech relevant to Stable Isotope work.

If you have any questions about the lab please email Andrew Campbell and if you have any questions about the website please email

Dr. Andrew Campbell
Dept. of Earth and Environmental Science
New Mexico Tech
Socorro, NM 87801

office and lab phone: 505-835-5327


Lab Capabilities

The stable isotope lab at New Mexico Tech is equipped with a Thermo Finnigan Delta Plus XP isotope ratio mass spectrometer.
We have the mass spec set up with several peripherals.


The H-Device is used to run D/H isotopes on water samples. It uses a chromium reactor at 850° C. Water reacts with the chromium to produce chromium oxide and hydrogen gas. The hydrogen gas proceeds to the mass spec to be analyzed. The H-Device is connected to the mass spec through the dual inlet system. The gas from the H-Device is stored in a bellows, and run against a standard Hydrogen gas stored in another bellows.


The EA is set up to measure sulfur and oxygen isotopes in sulfides and sulfates. It is connected to the mass spec through the ConFlo unit, which uses a constant flow of Argon gas as a carrier. The argon moves the sulfur and oxygen to the mass spec for analysis.

The EA can also function as a stand-alone unit. It is equipped with a laptop computer, and can return elemental percentages of Nitrogen, Oxygen and Sulfur for various samples.

The TCEA measures oxygen and hydrogen isotopes on hydrous minerals and on fluid inclusion waters. It is also connected to the mass spec through the ConFlo, using argon gas as a carrier.
Gasbench with heating block

The heating block can run oxygen isotopes on both water samples and carbonate rock samples. The samples react in sealed containers, from which the equilibrated CO2 is extracted through a needle and into the Gasbench. The Gasbench is connected to the mass spec. The Gasbench does not use a continuous flow of argon like the ConFlo, rather it regulates the flow of gases into the mass spec, one gas from the heating block, and one standard.

Both the heating block and the H-Device utilize the autosampler. The autosampler is an apparatus that moves a needle around to automatically sample from either the heating block or the H-Device. For the H-Device, the autosampler uses a 10 microliter syringe that it extracts water from vials with, and injects that water into the reactor. For the heating block, the autosampler uses a needle attached to capillary tube running to the Gasbench. This needle simply remains in the sample vial while the Gasbench controls the flow of gas from the needle into the mass spec.
Vacuum Extraction Lines

Our lab is also equipped with two vacuum extraction lines. One is used strictly for reacting silicate minerals to measure oxygen isotope ratios. The other line can be used for a number of different analyses. When a sample gas is extracted from a vacuum line, it can be run through the dual inlet system on the mass spec, where sample gas is stored in one bellows, and is measured against a standard gas in the other bellows.


Courses about Stable Isotopes at New Mexico Tech

There are two classes centered around stable isotope geochemistry at New Mexico Tech, both taught by Andrew Campbell.

GEOC 565

Stable Isotope Geochemistry Principles of stable isotope geochemistry with applications to geologic systems. (From NMT catalog)

GEOC 566

Practical Aspects of Mass Spectrometry Theory and application of stable isotope mass spectrometry. Through lectures, problem sets, and laboratory exercises, students learn how to analyze geologic samples to determine stable isotope composition (From NMT catalog)