Mass spectrometry of a volatile Mg chelate in the measurement of stable 26Mg when used as a tracer.
A method for the detection of 26Mg enrichment of natural Mg was developed based on mass spectrometry (MS) of a Mg chelate made by complexing Mg to 2,2',6,6'-tetramethylheptanedione (THD). The chelate [Mg(THD)2] was extracted at pH greater than 9 from dilute aqueous solutions into ethyl ether, recovered by sublimation at room temperature, and introduced by solid probe into a Finnigan 3300 mass spectrometer. The chelate was ionized by electron impact. Samples were heated to a maximum temperature of 200 degrees C at a rate of 700 degrees C/h. Each analysis required 1--5 micrograms Mg(THD)2. Enrichment levels as low as 5% above natural abundance could be detected satisfactorily. Precision was best at 26Mg enrichment levels of 8--40% above natural abundance, the levels most likely to be encountered in analysis of plasma, urine and fecal samples from experimental subjects who had received 26Mg as a tracer. The method was compared to neutron activation (NA) analysis and judged superior.
D002614:Chelating Agents; D005243:Feces / Q000032:analysis; D006801:Humans; D007554:Isotopes / Q000032:analysis; D007659:Ketones; D008274:Magnesium / Q000097:blood* / Q000652:urine; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D009501:Neutron Activation Analysis
D002614:Chelating Agents; D007554:Isotopes; D007659:Ketones; D008274:Magnesium