Stable Isotope Lab

The Stable Isotope Lab provides the following analyses:

δ¹³C and δ¹⁸O of carbonate
δ¹³C and δ¹⁵N in solid samples, such as soils, plant materials, and dried extracts (combustion)
δ³⁴S in solid samples
δ¹³C and δ¹⁵N and δ³⁴S in solid samples
δ²H and δ¹⁸O in solid organic samples (pyrolysis)
δ²H and δ¹⁸O in natural abundance, clean water
δ¹³C of dissolved inorganic carbon in water
δ¹³C and δ¹⁵N and atom% of 13C and 15N of enriched solid samples

The lab’s instrumentation consists of 4 analytical systems and various tools to prepare samples for isotope analysis. There are 3 continuous flow mass spectrometers coupled with several sample introduction systems and a Picarro L2130-i Isotopic Liquid Water Analyzer with an autosampler for rapid measurements of deuterium and oxygen.

Thermo Delta V IRMS – GasBench II

The Thermo Delta V IRMS is coupled with a GasBench II and autosampler allows rapid and automated generation of gases introduced into the mass-spectrometer for isotopic determinations.

Gas Bench II with a CombiPAL autosampler for the automated analyses of carbon and oxygen isotopes. The CO₂ gas is generated through acid digestion of carbonate samples.

The mass spectrometer is configured for high-precision isotope ratio analyses of carbon and oxygen. The long-term precision of this mass spectrometer is ±0.05‰ for δ¹³C and ±0.09‰ for d18O, respectively.

EA IsoLink IRMS System

This Delta V Plus IRMS is attached to a Flash IRMS Elemental Analyzer and duel inlet and is configured to measure C, N, S, O, and H isotopes.

Flash EA uses two high temperature ovens, interfaced with a ramped GC oven and Conflo IV, to convert solid samples into gases for isotopic analysis of carbon, nitrogen, and sulfur in one measurement.

The system is configured to analyze C,N, & S simultaneously. This device is also dedicated to sulfur isotope measurements. Contact the lab for an estimate and turnaround time.

ThermoFinnigan Delta Plus XL IRMS

The ThermoFinnigan Delta XL Plus IRMS is connected to three peripherals. These peripheral devices use different automated methods to convert samples into gases to be introduced into the mass spectrometer for isotopic determinations.

GasBench with a CombiPAL autosampler for the automated analysis of carbon isotopes in dissolved inorganic carbon (DIC).

Costech Elemental Analyzer with zero-blank autosampler attached to a Conflo III Interface for the analyses of bulk organic carbon and nitrogen isotopes in plants, animals, soils, sediments, and minerals through combustion.

Thermo Finnigan TC/EA (thermochemical elemental analyzer) with zero-blank autosampler attached to a Conflo III Interface for the automated analysis of oxygen isotopes in nitrates, sulfates, phosphates, and organic material. This device also allows the determination of hydrogen isotopes in silver encapsulated water and organic samples through high temperature pyrolysis.

The mass spectrometer is configured for high-precision isotope ratio analyses of hydrogen, carbon, nitrogen, and oxygen. The long-term precision of the mass spectrometer is ±0.08‰ for d13C and ±0.14‰ for d15N and ±0.11‰ for δ¹⁸O, respectively.

Sample Preparation Tools

We have 2 fully operational micromilling devices, which facilitate accurate, fine-scale, sampling of carbonate material. The MM2 micromill and Merchantek micromill with digital microscope are capable of several micrometer sampling steps.

The laboratory is equipped with devices to aid in the preparation and purification of samples for isotopic and elemental determinations. These facilities include a ballmill grinding device, freeze-dryer, microbalance, and precision saws.