Stable Isotope Laboratory

A cutting-edge facility for the analysis of C, N, O and H isotopes in environmental samples

The Skidaway Institute Scientific Stable Isotope Laboratory (SISSIL) is able to analyze an extremely wide range of environmental samples — a capability matched by no other lab in the Southeast. The Lab consists of
2 state of the art light stable isotope mass spectrometers with 5 interfaces, microbalance, hoods and other support equipment for sample preparation. Guest scientists and students are welcome to visit Skidaway and see firsthand this facility, and hands-on training is both possible and encouraged for larger projects.

One IRMS instrument is configured to analyze solid samples such as soils, liquids such as water, and volatile samples like hydrocarbons with a gas chromatograph. There is also a conventional Hewlett-Packard GC/MS for quantification and purity validation.

The second instrument has a complementary set of interfaces designed to measure the isotopic composition of gasses, dissolved ions and non-volatile organic compounds. It is capable of measuring, at very high precision, the isotope ratios of gases dissolved in water and in the atmosphere. It is also able to directly analyze the composition of organic molecules in water.  A recent method developed by Brandes allows for the rapid (<12 minutes, including prep) analysis of dissolved inorganic carbon in any water matrix at very high (~0.05 per mil) precision.  This capability is being used to investigate the photochemical reactivity of dissolved organic matter as well as dissolved black carbon sources.

The Skidaway Institute is surrounded by outdoor, natural laboratories, such as salt marshes, estuaries and the coastal ocean. Having the SISSIL facility located on our campus furnishes collaborating researchers and students with instant feedback on experimental results during their field studies. We have had many such successful collaborations with students from Savannah State, Georgia Southern, College of Charleston, and others.

Mass spec #1: Delta V plus (2007) Instrument has 2 interfaces:


1. Flash 1112 TC+EA for analysis of solid and liquid C, N, O and H isotopes. Types of samples : solids (soils, sediments, plants, filters) and water. Can measure H/D and 18O in liquids in one injection, or in solids in one sample, and 13C and 15N in solids in one sample.

2. Trace GC with Split/Splitless injectors and cool-on-column injector. System has both combustion (15N, 13C) and pyrolysis (H/D) furnaces. Used to measure isotopic composition of individual compounds separated by gas chromatography.

Mass spec #2: Delta V plus (2008)


Instrument has 2 interfaces plus Dual inlet for gas analyses:

1. Isolink LC-C-IRMS interface for the 13C analysis of DOC, DIC and organic compounds in aqueous solutions. Interface has quaternary mixing pump, Autosampler and manual injection modes.

2. Gas bench with cold finger preconcentrator. System is used to analyze the headspace gases in vials. In practice this means that it can analyze anything that can be chemically converted to a gas. Examples: 18O and 13C in carbonates, 18O and 15N in nitrate and nitrite, 15N in dissolved organic nitrogen or ammonium.