Other (carbonates, minerals, porewaters)

Sample Submission

Please send dried, ground (flour, ~200μm mesh) and well mixed sample. For ⁸⁷Sr/⁸⁶Sr analysis, provide sufficient material to produce a minimum of 10 µg of strontium (typically ~10 mg CaCO3). Screw top glass vials with tin-foil or plastic liners are preferred for minimum static problems.

Tips for sampling, labelling and shipping

Equipment

• δ¹³C and δ¹⁸O: The CO2 produced from carbonate digestion is extracted automatically with a double-hole needle Gilson auto-sampler connected to a GVI MultiFlow. The MultiFlow contains a 500-ul sample loop, and a GC column that separates CO₂, N₂, O₂ and H₂O. Helium carrier gas then transports the purified CO2 into the GVI IsoPrime continuous flow isotope ratio mass spectrometer system continuous flow mass spectrometer where it is analyzed.
• ⁸⁷Sr/⁸⁶Sr:  Acid digested and 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 Analysis:

• δ¹³C and δ¹⁸O: Minimum 10% duplicate analysis, repeated if not within specification (± 0.2‰); if still not within specification – trouble shoot with standards.
• ⁸⁷Sr/⁸⁶Sr: 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 2σ_x̅ is less than ±0.000015.

Calibration:

• δ¹³C and δ¹⁸O: Four calibrated standards, EIL-21 (traceable to NBS-18 and NBS-19) + IAEA-CO-1, IAEA-CO-8 and IAEA-CO-9 are normally used for normalization.  Additional/alternate standards of the same composition as the samples are included when possible. During a sample run, linearity checks are included using a suite of EIL-21 to produce a range of peak heights that encompass the expected sample peaks range. 
• ⁸⁷Sr/⁸⁶Sr: NIST-SRM-987 (⁸⁷Sr/⁸⁶Sr = 0.710245 2σ_x̅ ±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

EPSTEIN, S.E., Buchsbaum, R., Lowenstaum, H.A. and Urey, H.C. Revised carbonate-water isotopic temperature scale. Bulletin of the Seismological Society of America. 1953;64:1315

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.

LAND L. S. The isotopic and trace element geochemistry of dolomite: The state of the art. Society for Sedimentary Geology Special Publication. 1980;28:87-110.

MCCREA J.M. On the isotopic chemistry of carbonates and a paleo-temperature scale. Journal of Chemical Physics. 1950;18:849

Sample Submission

Provide sufficient material to produce a minimum of 3 mg of Cl^- or Br^- or 10 µg of strontium. The EIL does not perform silicate digestions so the mineral species of interest should be leachable utilizing either water or acid digestion.

Tips for sampling, labelling and shipping

Equipment

• δ³⁷Cl: The analysis of mineral samples for δ³⁷Cl isotope measurements is determined through gas chromatography isotope ratio mass spectrometry (GC-IRMS) utilizing an Agilent 7890B gas chromatograph equipped with a CTC Analytics PAL Autosampler and a Micromass IsoPrime continuous flow mass spectrometer.
• δ⁸¹Br: The analysis of mineral samples for δ⁸¹Br isotope measurements is determined through gas chromatography isotope ratio mass spectrometry (GC-IRMS) utilizing an Agilent 7890B gas chromatograph equipped with a CTC Analytics PAL Autosampler and a Thermo 253 continuous flow mass spectrometer.
• ⁸⁷Sr/⁸⁶Sr:  Acid digested and 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)

• δ³⁷Cl and δ⁸¹Br: For δ³⁷Cl the standards used include standard mean ocean chloride (SMOC) and two different in-house standards, one enriched and the other depleted relative to SMOC. For δ⁸¹Br analysis the standards used include standard mean ocean bromide (SMOB) and two different in-house standards, one enriched and the other depleted relative to SMOB. In a given run standards make up approximately 50% of the samples analyzed in order to effectively characterize linearity and time drift corrections. A minimum of four different analyses from a minimum of two independent 20 mL reaction vials are used to ensure repeatability and to rule out contamination or fractionation due to leakage. Sample precision is calculated using the standard deviation of a minimum of four acceptable results. The maximum allowable precision is 0.1‰.
• ⁸⁷Sr/⁸⁶Sr:  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 2σ_x̅ is less than ±0.000015. Calibration: NIST-SRM-987 (⁸⁷Sr/⁸⁶Sr = 0.710245 2σ_x̅ ±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.

WABER, H., and Smellie, J. Characterisation of pore water in crystalline rocks. Applied Geochemistry. 2008;23:1834-1861.

Sample Submission

Provide sufficient material to produce a minimum of 3 mg of Cl^- or Br^- or 10 µg of strontium. No preservation is required.

If analysis requires leaching of porewaters from silicate rock, the samples must first be ground and screened to a fine flour beforehand. A $50/sample pretreatment charge is applied for leaching and filtration. If rock samples are sent intact, an additional $100/sample pretreatment charge will be applied for pulverising and screening.

Tips for sampling, labelling and shipping

Equipment

The amount of material required is determined by the analyte concentration (mg/kg) in the soil or rock mass. A mass corresponding to the required yield is slurried in a 1:1 soil to water ratio using ultra-pure chloride free Milli-Q water. This mixture is oscillated at >120 RPM for 24 hours to allow for dissolution and leaching of all available ions then left to settle for an additional 24 hours. All available water is decanted and filtered to 0.45 μm.

• δ³⁷Cl: The analysis of mineral samples for δ³⁷Cl isotope measurements is determined through gas chromatography isotope ratio mass spectrometry (GC-IRMS) utilizing an Agilent 7890B gas chromatograph equipped with a CTC Analytics PAL Autosampler and a Micromass IsoPrime continuous flow mass spectrometer.
• δ⁸¹Br: The analysis of mineral samples for δ⁸¹Br isotope measurements is determined through gas chromatography isotope ratio mass spectrometry (GC-IRMS) utilizing an Agilent 7890B gas chromatograph equipped with a CTC Analytics PAL Autosampler and a Thermo 253 continuous flow mass spectrometer.
• ⁸⁷Sr/⁸⁶Sr:  Acid digested and 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)

• δ³⁷Cl and δ⁸¹Br: For δ³⁷Cl the standards used include standard mean ocean chloride (SMOC) and two different in-house standards, one enriched and the other depleted relative to SMOC. For δ⁸¹Br analysis the standards used include standard mean ocean bromide (SMOB) and two different in-house standards, one enriched and the other depleted relative to SMOB. In a given run standards make up approximately 50% of the samples analyzed in order to effectively characterize linearity and time drift corrections. A minimum of four different analyses from a minimum of two independent 20 mL reaction vials are used to ensure repeatability and to rule out contamination or fractionation due to leakage. Sample precision is calculated using the standard deviation of a minimum of four acceptable results. The maximum allowable precision is 0.1‰.
• ⁸⁷Sr/⁸⁶Sr:  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 2σ_x̅ is less than ±0.000015. Calibration: NIST-SRM-987 (87Sr/86Sr = 0.710245 2σ_x̅ ±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.

WABER, H. and Smellie, J. Characterisation of pore water in crystalline rocks. Applied Geochemistry. 2008;23:1834-1861.