High-precision measurement of variations in calcium isotope ratios in urine by multiple collector inductively coupled plasma mass spectrometry
Analytical Chemistry
By: J.L.L. Morgan, G.W. Gordon, R.C. Arrua, J.L. Skulan, A.D. Anbar, and T.D. Bullen
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Abstract
We describe a new chemical separation method to isolate Ca from other matrix elements in biological samples, developed with the long-term goal of making high-precision measurement of natural stable Ca isotope variations a clinically applicable tool to assess bone mineral balance. A new two-column procedure utilizing HBr achieves the purity required to accurately and precisely measure two Ca isotope ratios (44Ca/42Ca and 44Ca/43Ca) on a Neptune multiple collector inductively coupled plasma mass spectrometer (MC-ICPMS) in urine. Purification requirements for Sr, Ti, and K (Ca/Sr > 10000; Ca/Ti > 10000000; and Ca/K > 10) were determined by addition of these elements to Ca standards of known isotopic composition. Accuracy was determined by (1) comparing Ca isotope results for samples and standards to published data obtained using thermal ionization mass spectrometry (TIMS), (2) adding a Ca standard of known isotopic composition to a urine sample purified of Ca, and (3) analyzing mixtures of urine samples and standards in varying proportions. The accuracy and precision of δ44/42Ca measurements of purified samples containing 25 μg of Ca can be determined with typical errors less than ±0.2‰ (2σ).
Suggested Citation
Morgan, J., Gordon, G., Arrua, R., Skulan, J., Anbar, A., Bullen, T., 2011, High-precision measurement of variations in calcium isotope ratios in urine by multiple collector inductively coupled plasma mass spectrometry: Analytical Chemistry, v. 83, no. 18, p. 6956-6962, https://doi.org/10.1021/ac200361t.
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | High-precision measurement of variations in calcium isotope ratios in urine by multiple collector inductively coupled plasma mass spectrometry |
| Series title | Analytical Chemistry |
| DOI | 10.1021/ac200361t |
| Volume | 83 |
| Issue | 18 |
| Publication Date | August 18, 2011 |
| Year Published | 2011 |
| Language | English |
| Publisher | ACS Publications |
| Publisher location | Washington, D.C |
| Contributing office(s) | Water Resources Discipline |
| Description | 5 p. |
| Larger Work Type | Article |
| Larger Work Subtype | Journal Article |
| Larger Work Title | Analytical Chemistry |
| First page | 6956 |
| Last page | 6962 |