Hydrogen stable isotope ratios are critical indicators in environmental geochemical studies for characterizing runoff, determination of groundwater groups and water uptake by plants etc. (generally used in combination with 18 O analysis). While the common technique for this hydrogen isotope measurement is Mass Spectrometry, FTIR (Fourier transform infra-red) spectroscopy may be an alternative method, with the advantage of direct and simple operating measurements. The FTIR spectrometer has the advantage of performing in situ measurements, which can delineate continuous geochemical processes. In situ measurements decrease errors that may be a consequence of sample delivery to the laboratory and off-site analysis procedures. In this study, we have developed a new simple procedure for in situ hydrogen stable isotope ratio measurements. We discovered that the HDO (hydrogen, deuterium, and oxygen) absorbance peak at 2504 cm À1 is the most suitable for water sample direct analysis, with the FTIR device, using a circular sample cell for liquid samples. A case study analyzing water samples from a karstic cave (Sif cave, Israel) verified the following: (a) on-line determination of water D/H ratio can be carried out with the portable FTIR spectrometer (and thus can be used for field measurements such as in the Sif cave) and (b) the D concentration sensitivity achieved was at a 0.01& level, with a standard deviation of 0.006&.

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EPR spectroscopy of pre-color treated natural diamonds – yellow and green: correlation between natural pre colored diamond paramagnetic centers and nitrogen concentration.

Carbon stable isotope ratios measurement serves as an important implement for environmental geochemical processes study. While Mass spectrometry is commonly used for the task, FTIR (Fourier Transform Infra-Red) spectroscopy has the potential for determining these isotopic ratios with the advantage of simple in-situ measurements. Online analysis enables continuous processes monitoring and decreases sampling errors, caused by the sampling and the laboratory analysis procedures (e.g. for measurement in the mass spectrometer). Variance in carbon stable isotope ratios are results of waterrock interactions, phase transitions, changes in ambient temperature and humidity, biochemical reactions and more. In this study carbon isotope ratios were measured using FTIR spectrophotometer in both field and in laboratory conditions and corroboration of the analysis validity was done by Mass spectrometer measurements. The research results suggest that: Carbon isotope ratio (13 C/ 12 C) may be determined by FTIR spectroscopy of the CO 2 released from water samples under acidic conditions. As a case-study, FTIR analysis was used for characterizing phase transitions and water-rock interactions of runoff infiltrating a cave. By profiling the stable isotope systems, we have found that the 13 C values, which were calculated using FTIR showed sufficient agreement to those of the Mass Spectrometer measurements. A case study analyzing water samples from karstic cave (Sif cave, Israel), verified that: (a) On line determination of water 13 C/ 12 C ratio can be carried out with the portable FTIR spectrometer, hence can be taken to field measurements as preformed in the Sif cave. (b) The C concentration sensitivity achieved was 7‰ in δ values, which is applicable for most carbon stable isotopes applications.

The modification of nitrogen-contaminated diamonds into color-enhanced diamonds is usually achieved by irradiation and thermal treatment (annealing).