News

09.07.2018

Collaboration in international evaluation of isotopic analysis of water (∂18O & ∂2H)

The stable isotope laboratory (Isotopic ratio mass spectrometry technology) of CCiTUB has participated in an international water isotope inter-comparison test, this test was organized by International Atomic Energy Agency (IAEA), Vienna.

Number of participants: 235 international laboratories.
5 core test sample were distributed:

Water stable isotope ratios (∂18O i ∂2 H ) are widely used as tracers in environmental studies. Accurate and precise assays are required for providing sound scientific information.

The instrumentation used for measuring (∂18O i ∂2 H ) is classified into three types:
1-dual-inlet isotope-ratio mass spectrometry (DI-IRMS),
2-contiuous flow isotope ratio-masspectrometry (CF-IRMS)
3- laser-absorption spectrometry (LAS).

A comparative statistical test between all the data of the participant laboratories has been performed in criteria the z-score in order to determinate acceptable and unacceptable results for accurate and precisse assays.

73% of laboratories gave acceptables results. The stable isotope laboratory (Isotopic ratio mass spectrometry technology) of CCiTUB is enclosed in this group of participants.

The stable isotope laboratory (Isotopic ratio mass spectrometry technology) of CCiTUB performed the analysis by CF-IRMS, in 2 instrumentation and 2 different configurations:
1-CF- GasBench- coupled to Isotopic Ratio Mass Spectrometry (IRMS) GasBench I-Mat253 (Thermofisher).
2-CF-Pyrolisis-coupled to Isotopic Ratio Mass Spectrometry (IRMS), TC/EA-Delta plus xp (Thermofisher).

Internal methodologies used in this work: instrumentation maintenance, calibration standards, storage of samples and standards, criteria of calibration and normalization of results and reports and uncertainty of measurement of results uncertainty.

GASBENCH - MAT253