As the demand of extraction and consumption of groundwater increases, its quality has been facing the issue of water contamination caused by industrial as well as domestic activities. Isotopic ratio analysis is a modern and effective technique widely used to trace the source of groundwater contamination. In this study, an analytical technique for carbon stable isotopic ratio of dissolved inorganic carbon in groundwater using elemental analyzer - isotopic ratio mass spectrometer was utilized under the condition in Vietnamese lab. As a result, correlation and calibration equations were established in which good reproducibility of the international standards was achieved with the value of first standard deviation less than 0.3 ‰ as well as the accuracy and precision of the measurements were obtained with errors less than 0.12 ‰. Based on these equations, 15 samples of groundwater collected from Cu Chi (Viet Nam) district were analyzed and calculated.
isotopic ratio, carbon, dissolved inorganic carbon, EA-IRMS, groundwater.