Analysis of dicarboxylic acids by tandem mass spectrometry. High-throughput quantitative measurement of methylmalonic acid in serum, plasma, and urine
MM Kushnir, G Komaromy-Hiller, B Shushan… - Clinical …, 2001 - academic.oup.com
MM Kushnir, G Komaromy-Hiller, B Shushan, FM Urry, WL Roberts
Clinical chemistry, 2001•academic.oup.comBackground: Methylmalonic acid (MMA) is a dicarboxylic acid whose concentration can be
increased in blood and urine in patients with an inborn error of metabolism or vitamin B12
deficiency. We developed a method for the selective analysis of dicarboxylic acids that
exploits the high specificity of tandem mass spectrometry (MS/MS) and the substantial
difference in fragmentation patterns of the isomers methylmalonic (MMA) and succinic acid
(SA). Methods: Dicarboxylic acids were extracted from samples with methyl-tert-butyl ether …
increased in blood and urine in patients with an inborn error of metabolism or vitamin B12
deficiency. We developed a method for the selective analysis of dicarboxylic acids that
exploits the high specificity of tandem mass spectrometry (MS/MS) and the substantial
difference in fragmentation patterns of the isomers methylmalonic (MMA) and succinic acid
(SA). Methods: Dicarboxylic acids were extracted from samples with methyl-tert-butyl ether …
Abstract
Background: Methylmalonic acid (MMA) is a dicarboxylic acid whose concentration can be increased in blood and urine in patients with an inborn error of metabolism or vitamin B12 deficiency. We developed a method for the selective analysis of dicarboxylic acids that exploits the high specificity of tandem mass spectrometry (MS/MS) and the substantial difference in fragmentation patterns of the isomers methylmalonic (MMA) and succinic acid (SA).
Methods: Dicarboxylic acids were extracted from samples with methyl-tert-butyl ether and derivatized with butanolic HCl to form dibutyl esters. The derivative was injected into the liquid chromatography (LC)-MS/MS system using TurboIonSprayTM (nebulizer-assisted electrospray) ionization and quantified by the multiple reaction monitoring mode of MS/MS.
Results: The assay for MMA was linear up to 150 μmol/L. The total imprecision was ≤7.5% at both low and high concentrations. The limits of quantification and detection were 0.1 and 0.05 μmol/L, respectively. The degree of interference from SA could be predicted from the branching ratios of the major product ions.
Conclusions: The method is specific for dicarboxylic acids. The LC-MS/MS analysis for MMA requires minimal chromatographic separation and takes <60 s per sample. The entire analysis, including sample preparation, for a batch of 100 specimens can be performed in <4 h.
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