AN IMPROVED NICKEL-TUBE PYROLYSIS METHOD FOR OXYGEN-ISOTOPE ANALYSIS OF ORGANIC-MATTER AND WATER

A revised method for oxygen isotope analysis of organic matter and wat er has been developed using resealable nickel pyrolysis bombs and a si mplified operating procedure. Broad variations in the CO/CO2 ratio occ ur during the pyrolysis reaction, independent of the oxygen isotope co mposition of the CO2, suggesting that isotopic equilibrium between the two gases at high temperature (950-degrees-C) is retained as the bomb s cool to room temperature. As a result, the deltaO-18-value of the sa mple can be obtained directly from the CO2, eliminating the need for n ickel powder catalyst to enhance CO-CO2 conversion or the use of a spa rk discharge chamber to recover oxygen from CO. The method is well sui ted for rapid analysis of cellulose and other organic tissues and smal l (less-than-or-equal-to 5 mul) water samples.