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University of Wisconsin–Madison

Mass Spectrometry / Proteomics Facility

Isotope Ratio Lab

We are open for business! We are happy to be back. During Phase 1, we will be operating at reduced capacity. We will make every effort to keep turnaround times short as we understand there are many projects that have been waiting. We appreciate your patience and business. The UW Biotechnology Center is following University guidelines regarding COVID-19.



Thermo Delta Plus Isotope Ratio Mass Spectrometer used extensively for the measurement of 2H/1H in water using a chromium reduction inlet.  This magnetic sector instrument is optimized for hydrogen isotope ratio analysis of water samples between 0.2 and 1 g, although analysis of samples as small as 1 uL can be performed. The precision of the d2H measurement is 0.5 permil or 0.08 ppm.

Thermo Delta V Isotope Ratio Mass Spectrometer used extensively for the measurement of 13C/12C, 15N/14N, 18O/16O.  The instrument is equipped with gas bench and elemental analyzer inlets.  The gas bench is used for measurement of 13C/12C in carbon dioxide, and 18O/16O in water by equilibration with carbon dioxide. Specimen size for carbon dioxide is 0.05 mL (STP) and water is 1 g. Precisions are d13C = 0.1 permil (1 ppm) and d18O = 0.1 permil (0.06 ppm).  The elemental analyzer is used for bulk sample analysis of 13C/12C and 15N/14N.  Sample size is 0.5 mg of organic material.  Precisions are d13C = 0.1 permil (1 ppm) and d15N= 0.2 permil (0.6 ppm).

Picarro L2140-i Cavity Ring-down Analyzer used for the analysis of 1H/2H, 18O/16O and 17O/16O in water.  Water specimens of 0.2 g are required, but smaller samples can be analyzed upon special request. Precisions are d2H = 0.1 permil (0.02 ppm) and d18O = 0.03 permil (.02 ppm).