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Secondary ion mass spectrometry techniques are used to study trace elements in organic samples where matrix compositions vary spatially. This study was conducted to develop calibrations for lithium content and lithium isotope measurements in kerogen. Known concentrations of Li ions (6Li and 7Li) were implanted into organic polymers, with a range of H/C and O/C ratios similar to kerogen, along with glassy carbon (SPI Glas‐22) and silicate glass (NIST SRM 612). Results show that Li content calibration factors (K*) are similar for carbonaceous samples when analysed using a 5kV secondary ion accelerating voltage. Using a 9 kV secondary ion accelerating voltage, K* factors are negatively correlated with the sample O content, changing ~ 30% between 0 and 15 oxygen atomic %. Thus, to avoid the matrix effect related to O content, using a 5 kV secondary ion accelerating voltage is best for quantification of Li contents based on 7Li+/12C+ ratios. Under these analytical conditions, Li ppm (atomic) = (132 ( 8) × 7Li+/12C+) × 12C atom fraction of the sample measured. Lithium isotope ratio measurements of SPI Glas‐22 and NIST SRM 612 are within uncertainty; however, the organic polymer samples as a group show a 10‰ higher δ7Li than NIST SRM 612.
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Progress in High-Precision Mass Measurements of Light Ions
Significant advances in Penning trap measurements of atomic masses and mass ratios of the proton, deuteron, triton, helion, and alpha-particle have occurred in the last five years. These include a measurement of the mass of the deuteron against 12C with 8.5 × 10−12 fractional uncertainty; resolution of vibrational levels of H2+ as mass and the application of a simultaneous measurement technique to the H2+/D+ cyclotron frequency ratio, yielding a deuteron/proton mass ratio at 5 × 10−12; new measurements of HD+/3He+, HD+/T+, and T+/3He+ leading to a tritium beta-decay Q-value with an uncertainty of 22 meV, and atomic masses of the helion and triton at 13 × 10−12; and a new measurement of the mass of the alpha-particle against 12C at 12 × 10−12. Some of these results are in strong disagreement with previous values in the literature. Their impact in determining a precise proton/electron mass ratio and electron atomic mass from spectroscopy of the HD+ molecular ion is also discussed.
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- Award ID(s):
- 1912095
- PAR ID:
- 10526886
- Publisher / Repository:
- MPDI
- Date Published:
- Journal Name:
- Atoms
- Volume:
- 12
- Issue:
- 8
- ISSN:
- 2218-2004
- Page Range / eLocation ID:
- 1-20
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/atoms12020008
