A mass spectrometric system for the analysis of noble gases and tritium from water samples
The design, setup, and performance of a mass spectrometric system for the analysis of noble gas isotopes ({sup 3}He, {sup 4}He, {sup 20}Ne, {sup 21}Ne, {sup 22}Ne, {sup 36}Ar, {sup 40}Ar, {sup 84}Kr, {sup 136}Xe) and tritium ({sup 3}H) from water samples are described. The {sup 3}H concentration is measured indirectly by the {sup 3}He ingrowth from radioactive decay. After extraction, purification, and separation, the noble gases are measured in two noncommercial double-collector 90{degree} magnetic sector mass spectrometers. The authors present a new approach for the analysis of the heavy noble gas isotopes that enables, in principle, simultaneous measurement of Ar, Kr, and Xe. Typical precisions of the measurements of {sup 3}H, He, Ne, Ar, Kr, and Xe concentrations are {+-}2.7%, {+-}0.3%, {+-}0.9%, {+-}0.3%, {+-}0.8%, and {+-}1.0%, respectively. For the isotopic ratios {sup 3}He/{sup 4}He, {sup 20}Ne/{sup 22}Ne, and {sup 40}Ar/{sup 36}Ar the typical precisions are {+-}0.7%, {+-}0.3%, and {+-}0.2%. These values express the reproducibility of the measurement of an internal freshwater standard and include the overall stability of the system as well as of the extraction procedure. To verify the method, the noble gas concentrations of air-saturated water samples prepared under controlled conditions are compared with noble gas solubility data. The {sup 20}Ne/{sup 22}Ne and {sup 36}Ar/{sup 40}Ar fractionation during solution is estimated from 70 surface water samples to be {minus}2.0 {+-} 0.2% and {minus}1.3 {+-} 0.2%, respectively.
- Research Organization:
- Swiss Federal Inst. of Tech., Dubendorf (SE)
- OSTI ID:
- 20080467
- Journal Information:
- Environmental Science and Technology, Vol. 34, Issue 10; Other Information: PBD: 15 May 2000; ISSN 0013-936X
- Country of Publication:
- United States
- Language:
- English
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