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Realised by ALMS™
developer of the AIDS-HIV Reference project
Abstract No.: MoP-158
Session: Metabolomics, Metabonomics
Presentation date: Mon, Aug 28, 2006
Presentation time: 14:30 – 16:00

Desorption/Ionization on Porous Silicon for Ultrasensitive Metabolome Analysis

Andrea Amantonico1, Renato Zenobi1

1 ETH Zurich, Zurich, Switzerland

Correspondence address: Andrea Amantonico, ETH Zurich, Department of Chemistry and Applied Biosciences, Wolfgang-Pauli-Str. 10, Zurich, CH-8093 Switzerland.

Keywords: Ionization, Laser; MALDI; Metabolism, Metabolites; Phosphates.

Novel aspect: Ultrasensitive metabolome analysis.

 

Metabolome analysis is crucial for studies of drug toxicity and efficiency, and provides key information in functional genomics and for the development of efficient "cell factories". Mass spectrometry (MS) is already well established as tool for identification and quantification of metabolites. For this purpose, MS is usually coupled with separation techniques, which requires long analysis time and, in some cases, laborious sample preparation.

In this study we use desorption/ionization on porous silicon mass spectrometry (DIOS-MS) for the identification of endogenous metabolites in microorganism such as Escherichia coli. This technique, introduced in 1999 by Siuzdak and co-workers,1 is capable of high throughput analysis and is extremely sensitive even in the absence of laborious sample clean-up procedures.2 The low abundance of some metabolites represents a challenge in metabolome analysis, which could be met by DIOS-MS.

The physical and the chemical proprieties of the silicon active surface are critical for DIOS-MS analysis. The surfaces of commercial DIOS target plates were chemically modified with different functional groups. The performances of modified silicon surfaces were tested on a set of ten endogenous metabolites. The spectra show that amino-functionalized surfaces are particularly suitable for the detection of phosphate containing metabolites in negative mode. For the sake of comparison, the same metabolites were also analyzed with matrix-assisted laser desorption/ionization (MALDI) MS. DIOS-MS appeared more sensitive for the compounds analyzed with a limit of detection for some of them at the low attomole level. Finally DIOS-MS and MALDI-MS were applied for the analysis of metabolites in Escherichia Coli. Different sample preparations were performed with the aim of comparing the sensitivity of these two techniques in a complex biological matrix.

1. J. Wei, J. M. Buriak, and G. Siuzdak, Nature 399, 243 (1999).
2. S. A. Trauger, E. P. Go, Z. Shen, J. V. Apon, B. J. Compton, E. S. P. Bouvier, M. G. Finn, and G. Siuzdak, Anal. Chem. 76, 4484 (2004).