Task 8.2: Water isotopes

In situ and continuous measurements of water isotopes: the CRDS Picarro L2130i

The Cavity Ring-Down Spectroscopy (CRDS) is an isotopic analyzer that allows the simultaneous measurement of the isotopic composition of the water molecule in 2H and 18O continuously. It therefore makes it possible to know where the water comes from and which physical or biological processes have affected it.

This instrument uses the absorption properties of the water molecule in the near infrared.

This analyzer is an analyzer for fast and accurate measurement.

CRDS Picarro L2130i

The analysis was carried out with two different devices:

  • In injection mode (laboratory); The liquid sample is injected into a vaporizer and then into a combustion module, eliminating interference due to the dissolved organic matter. The duration of the measurement is 8 minutes per sample (10 injections / measurements per sample)
  • In real-time measurement mode; The pre-filtered sample (0.2 μm) is analyzed at high frequency (every 10s), allowing real-time measurements, for example during flood periods.

The CRDS is intended to be installed on the hydrogeological sites of the CRITEX project. Technical training is required in the laboratory prior to field installation.

WP leader: Mathieu Sebilo