Syringe life and memory effects in isotopic analyses performed by liquid water isotopic analysers – a case study for natural waters from central Europe^†

† Originally presented at the IAEA International Symposium on Isotope Hydrology: Revisiting Foundations and Exploring Frontiers, 11–15 May 2015, Vienna, Austria.

ABSTRACT

Syringes are the most expensive consumables for analyses in the Liquid Water Isotope Analyser using commercial Cavity Ring-Down Spectroscopy (CRDS) systems. Our experience shows that although the syringe life significantly varies, it is not an exception that a syringe performs many thousands of injections. A simple maintenance procedure consisting of replacing the syringes two times per day and keeping them in the deionised water resulted in an average syringe life of over 3500 injections. Number of injections per sample affects the between-sample memory effect and the cost of the analysis (duration, energy, consumption of syringes). We studied the influence of the number of injections (six and nine) on the final δ¹⁸O and δ²H values using two sets of samples covering the ranges of isotopic composition typical for the natural waters of the highest part of the Carpathians (streams, springs, soil water and precipitation). The differences in the final δ-values between nine and six injections were within 0.1 ‰ for δ¹⁸O and 1.0 ‰ for δ²H for the Picarro 2120i and 2130i CRDS systems.

KEYWORDS:

• Hydrogen-2
• isotope measurements
• methods and equipment
• laser spectroscopy
• LIMS for lasers
• memory effect
• number of injections
• oxygen-18
• syringe life
• water

Acknowledgements

I would like to thank the IAEA and Mr L. Wassenaar for allowing me to participate in the laser spectroscopy course and sharing the experience with laser spectroscopy, Mr M. Šanda for practical advice on sample preparation and standards and Mr J. Shanley for the revision of English. Comments by the editor and two anonymous reviewers which helped to improve the manuscript are highly appreciated as well.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

† Originally presented at the IAEA International Symposium on Isotope Hydrology: Revisiting Foundations and Exploring Frontiers, 11–15 May 2015, Vienna, Austria.

Additional information

Funding

We would like to acknowledge financial support from the European Regional Development Fund Projects 26220120062 ‘Centre of excellence for the integrated river basin management in changing environmental conditions’ and 26210120009 ‘Completion of infrastructure of hydrological research stations’, which allowed purchase of the equipment. This study was supported by the Ministry of Education, Science, Research and Sport of the Slovak Republic through project VEGA 2/0055/15.