FTIR SPECTROSCOPY AS A TOOL FOR STABLE ISOTOPES RATIO ANALYSIS IN ENVIRONMENTAL RESEARCH
Measurement of carbon, oxygen and hydrogen stable isotope ratios is an important tool for characterizing environmental geochemistry processes. While Mass spectrometry is commonly used for measuring these ratios, FTIR (Fourier Transform Infra-Red) spectroscopy has the potential for measuring these isotopic ratios in a relatively simple manner that also enables In-situ measurements. The importance in direct measurements is mainly significant reduction in sampling errors, caused by transport of the samples to the lab and the preparation procedure of the sample for measurement in the mass spectrometer.
Variance in stable isotope ratios in water solutions may be result of water-rock interactions, ambient temperature and humidity, sample age etc. In this study we examined the possibility of using FTIR spectrophotometer for measuring the isotope ratios of carbon, hydrogen and oxygen, whereas the corroboration of the analysis validity was done by Mass spectrometer measurements.
In conclusion:
Carbon isotope ratio was determined by FTIR gas cell measurements of CO2 extracted from the water solution with hydrochloric acidic.
Isotopes of oxygen in aqueous solution can be determined by electrolysis of the water and evaluation of the isotopes in O2 gas in the FTIR gas cell.
The sensitivity of the FTIR in direct measurement was sufficient for aqueous solution with 10ppm concentration of D2O.
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