Concepedia

Abstract

A rapid, inexpensive on-line technique for the analysis of stable isotopes of oxygen in organic matter and water is described. The oxygen in the sample is pyrolysed over nickelized carbon using a modified Unterzaucher technique and converted to carbon monoxide. Separation of the CO from N2 by gas chromatography before mass spectrometric measurement of the 18O/16O ratio allows application of the technique to nitrogen containing samples. The precision of measurements is generally as good as, or better than, that obtained with other methods (σ = 0.2‰ for n = 10). A major advantage of the method is its speed, each sample taking less than 7 minutes to analyse. The technique improves on those used previously, in being applicable to a wide range of samples including N-containing organic matter and water and in being rapid, simple and inexpensive while retaining precision. © 1997 John Wiley & Sons, Ltd.