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Preparation of 14C‐labeled nutrient metabolites for AMS measurement of 14C
Author(s) -
Kim SeungHyun,
Kelly Peter B,
Clifford Andrew J
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a724-a
Subject(s) - graphite , zinc , micronutrient , radiochemistry , chemistry , mass spectrometry , accelerator mass spectrometry , catalysis , fractionation , chromatography , nuclear chemistry , biochemistry , organic chemistry
Accelerator Mass Spectrometry (AMS) is the most sensitive method for the quantitation of 14 C‐labeled micronutrients at attomole levels. Sample preparation requires the formation of filamentous graphite. The graphitization process consists of oxidation and reduction steps. The objective of this study was to optimize even more the conditions for good quality graphite, especially the zinc reduction step. We find the optimal graphite formation using the following conditions: 50 mg zinc, 10 mg iron (325‐mesh) and 5 h reduction time at 525 °C. These conditions use a smaller amount of zinc, bigger particle size of the iron catalyst and a shorter reduction time than we have previously reported. We also demonstrated the degree of graphite formation onto different catalysts and its physical appearance with scanning electron microscopy. These modifications appear to work well for 14 C‐metabolites isolated by HPLC fractionation. Work performed under the auspices of the US DOE by the University of California, LLNL under Contract No. W‐7405‐Eng‐48, NIH NCRR P41 RR 13461, and NIDDK DK48307.