RESUMEN
A method for the automated sample conversion and on-line oxygen isotope ratio (delta(18)O) determination for organic and inorganic substances is presented. The samples are pyrolytically decomposed at 1400 degrees C in the presence of nickelized graphite. With the system presented organic as well as inorganic samples such as nitrates, sulphates and phosphates of 50-100 &mgr;g O can be analyzed for their delta(18)O values with a standard deviation usually better than 0.5 per thousand. Additionally, carbon isotope ratios of organic substances and nitrogen isotope ratios of inorganic nitrogenous compounds are available in the same sample run. Data for international and some inter-laboratory reference materials are presented to show the accuracy and reliability of the method. The effect of some additives on the CO yield was checked for substances which do not pyrolyze completely. Copyright 1999 John Wiley & Sons, Ltd.
RESUMEN
Abstract A new technique for the sample preparation and direct coupling to an Isotope Ratio Mass Spectrometer (IRMS) for the D/H-determination is described. 1 µl size samples of water are injected and reduced with chromium metal in a novel reaction furnace. The hydrogen gas flows directly into the IRMS and is analysed (standard/sample comparison). The reproducibility is about 1 %. The accuracy of the technique was proven by means of the IAEA-standard waters V-SMOW, GISP, SLAP.