Direct tandem mass spectrometric analysis of amino acids in dried blood spots without chemical derivatization for neonatal screening

Abstract

Neonatal screening performed by electrospray tandem mass spectrometry is a powerful technique in clinical diagnostics. In the present paper an alternative to the widely accepted method involving butylation has been developed. In the new method butylation is not required, and multiple reaction monitoring (MRM) was used instead of constant neutral loss scanning. The method was optimized for detection of 23 L-amino acids in their native form. Quantitation was based on isotope-labeled internal standards, calibration curves were linear from 0 to 500 micromol/L, and detection limits were in the range 2-42 micrmol/L. The utility of the present technique is illustrated in the case of one neonate suffering from citrullinaemia.

Analysis of whole body ammonia metabolism in Aedes aegypti using [15N]-labeled compounds and mass spectrometry

“…Methanol and acetonitrile were obtained from EMD Chemicals Inc. (Gibbstown, NJ, USA). N, N-Dimethylformamide Multi-reaction monitoring (MRM) scan is a mass spectrometry technique which can detect the compound of interest from a mixture with high sensitivity and selectivity (Vogg et al, 1999;Nagy et al, 2003). In the present study, MRM scan was performed in a triple quadrupole mass spectrometer with two mass analyzers and a collision cell.…”

Mass spectrometry in metabolome analysis

“…The ESI-MS method is a good alternative to the current methods, and enabled the high-throughput analysis of VLCFAs. Another interesting example recently published by Nagy et al (2003) is the method for the analysis of 19 amino acids in dry blood spots. Compared to the well-established method that includes a butyl-esterification of the free carboxyl groups of amino acids to enhance the electrospray ionization efficiency (Rashed et al, 1995;Chace et al, 1996Chace et al, , 1998Shigematsu et al, 1999;Zytkovicz et al, 2001), the new method does not require any derivatization of the amino acids before ESI-MS-MS analysis.…”

Development of Analytical Methods Utilizing Selectivity of Fluorous Affinity and Their Applications

“…Direct tandem MS methods have been developed for the screening of metabolic disorders by determining amino acid levels rapidly [25][26][27]. Although these methods have allowed effective and economic analysis of amino acids, direct injection of biological sample solutions without chromatographic column separation often causes inaccurate quantification results and shortening of the MS instrument lifetime.…”