Extraction of Magnesium from Biological Fluids Using 8-Hydroxyquinoline and Cation-Exchange Chromatography for Isotopic Enrichment Analysis Using Thermal Ionization Mass Spectrometry
✍ Scribed by N.E. Vieira; A.L. Yergey; S.A. Abrams
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 463 KB
- Volume
- 218
- Category
- Article
- ISSN
- 0003-2697
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✦ Synopsis
The use of 8-hydroxyquinoline to precipitate magnesium was evaluated as a method for preparing biological samples for isotopic enrichment analysis using thermal ionization mass spectrometry (TIMS). Standard curves in matrices of water, serum, and urine were prepared using varying amounts of ({ }^{25} \mathbf{M g}). The ({ }^{25} \mathbf{M g} /{ }^{24} \mathbf{M g}) isotope ratio was measured by TIMS using a silica gel/ phosphoric acid technique. Although the total Mg recovered by precipitation from the matrices varied considerably and was dependent on matrix, recovery was sufficient for isotopic enrichment analysis. Urine samples required cation-exchange chromatography (BioRex AG 50W-X8 filter membrane, Bio-Rad Laboratories) prior to precipitation to remove contaminants which interfered with the thermal ionization process. The observed versus expected ({ }^{25} \mathbf{M g} /{ }^{\mathbf{2 4}} \mathbf{M g}) enrichments were evaluated using linear regression analysis: water, (y=0.016+1.022 x); serum, (y=0.5+1.097 x); urine, (y=) (-0.004+0.943 x). This method has proven useful for the isolation of magnesium from the biofluids tested.