Abstract
Gas chromatography/pyrolysis/isotope ratio mass spectrometry (GC/P/IRMS) is a relatively new method for on‐line determination of 2H/1H isotope ratios. The influence of different parameters on the 2H/1H isotope ratios obtained in GC/P/IRMS has been thoroughly studied using several flavor compounds, such as 5‐nonanone, linalool, menthol, linalyl acetate and 4‐decanolide. The requirement of ‘conditioning’ the pyrolysis reactor to obtain reliable δ2HV−SMOW values is discussed. Furthermore, the influence of the carrier gas flow of the gas chromatograph on the completeness of pyrolysis and subsequently on the δ2HV−SMOW values is investigated in detail. The linear range of the compounds investigated is determined. The results show that calibrating the GC/P/IRMS system with secondary standard substances is absolutely necessary in order to obtain reliable δ2HV−SMOW values. In view of interlaboratory comparability, validation procedures are recommended. Copyright © 2002 John Wiley & Sons, Ltd.