Discrepancies between isotope ratio infrared spectroscopy and isotope ratio mass spectrometry for the stable isotope analysis of plant and soil waters (original) (raw)

The increasing use of isotope ratio infrared spectroscopy (IRIS) for stable hydrogen and oxygen isotope analysis of water may introduce substantial errors due to contaminants, unlike isotope ratio mass spectrometry (IRMS). In this study, the performance of IRIS compared to IRMS was evaluated using water samples from 11 plant species and an organic soil horizon. Results indicated IRIS showed significant deviations from IRMS in over half the samples tested, with deviations up to 46% for d2H and 15.4% for d18O, despite using activated charcoal to remove contaminants. The findings highlight the necessity for new cleaning techniques and instrument modifications to improve the accuracy of IRIS in analyzing contaminated water samples.