Centres Científics i Tecnològics UB



New PICARRO-CRDS (Cavity ring-down spectroscopy) equipment for isotopic analysis of the water molecule (δ2H and δ18O).

The Environmental Unit of the CCiTUB has a new instrument that allows the isotopic analysis of δ2H-H2O and δ18O-H2O in water samples, both surface and groundwater with conductivities lower than 10.000 μS/cm. The instrument installed is a Picarro L2130i with a vaporizer HDS-2412 that uses the technology L-CRDS that allows to measure with great precision the isotopic composition of the H and the O using a volume of sample of 18 μL. In addition, the equipment has an automatic sampling system that allows the total automation of the sequences as well as obtaining more robust results in less time. The equipment uses an optical spectroscopy technology based on the capacity of gases to absorb radiation of certain wavelengths. The equipment measures the time that the light decays to 0 inside the cavity where the photodetector is located when the laser stops emitting (ring-down) and determines from this time the concentration of the gas as well as the isotopic composition of the molecule (Bushc and Bushc 1997). Most applications of these isotope analyses are within the field of isotope geochemistry, both in Earth and Environmental Sciences, as well as they have been used in Food Sciences.

The equipment, installed in the laboratories that the Environmental Unit has located in the Faculty of Earth Sciences, is now completely operational and complement the existent equipment in the Units that have isotope-ratio mass spectrometry technologies.


K.W. Busch and M.A. Busch (1997). "Cavity ring-down spectroscopy: An ultratrace absorption measurement technique." ACS Symposium Series 720, Oxford.

Picture of the new instrument: