Sample Requirements for Dissolved Strontium
|
Analysis |
Amount |
Precision |
|
87Sr/86Sr |
>10 µg Sr |
2σx̄ = 0.00002 |
Sample Submission
Provide sufficient water to produce a minimum of 10 µg of strontium as well as major ion geochemistry. High density polyethylene (HDPE) bottles are preferred. No preservation or field sample preparation is required. Holding time is infinite.
Tips for sampling, labelling and shipping
Equipment
Purified strontium is loaded on 1-2 zone-refined degassed Re filaments and is ionized and analyzed for 87Sr/86Sr utilizing a Thermo-Finnegan Triton thermal ionization mass spectrometer (TIMS).
Quality Assurance / Quality Control (QA/QC)
- Duplicate Analyses: A minimum of one in five samples is repeated to ensure repeatability. Sample precision is calculated using approximately 200 discrete measurements per sample. The variability of these 200 measurements is used to calculate precision. Acceptable 2σ for measured 87Sr/86Sr is less than ±0.0003 and 2σx̅ is less than ±0.000015.
- Calibration: NIST-SRM-987 (87Sr/86Sr = 0.710245 2σx̅ ±0.000015) is used to calibrate results, standard normalization and to correct for Rb interference. Several in-house standards are used to ensure linearity if sample ratios differ significantly from the accepted NIST-SRM-987 value of 87Sr/86Sr (~0.71).
References
HORWITZ, E.P., Dietz, M.L., and Chiarizia, R. The application of novel extraction chromatographic materials to the characterization of radioactive waste solutions. Journal of Radioanalytical and Nuclear Chemistry. 1992;161(2):575-583.