Determination of serum physiological concentration of methylmalonic acid by gas chromatography-mass spectrometry with selected ion monitoring.
We developed a sensitive assay for the rapid determination of serum methylmalonic acid concentration using capillary gas chromatography-mass spectrometry (GC/MS) with selected ion monitoring and a simple solid-phase extraction. The assay was linear up to 10,000 nmol/L and had a detection limit < 50 nmol/L, average recovery of 98% and between-day coefficient of variation at concentrations of 570 and 2206 nmol/L of 7.7% and 5.4%, respectively (n = 25). Comparison with another validated GC/MS method using sera with a wide range of methylmalonic acid concentrations (94-2020 nmol/L) revealed a slope and intercept of 0.97 and 17 nmol/L, respectively (n = 38). Methylmalonic acid concentrations determined by this assay in a group of apparently healthy individuals ranged from 64-331 nmol/L (n = 81). We conclude that the method is ideally suited for the determination of methylmalonic acid at physiological concentrations in both clinical and research laboratories.
Department of Laboratory Medicine, Children's Hospital, Boston, MA 02115, USA. rifai@a1.tch.harvard.edu
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Rifai
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Hagen
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Bradley
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Sakamoto
D001681:Biological Assay; D002849:Chromatography, Gas / Q000379:methods*; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D008764:Methylmalonic Acid / Q000097:blood*; D012680:Sensitivity and Specificity
D008764:Methylmalonic Acid