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Optimization of a capillary electrophoresis method for the
determination of the amino acid β-N-methylamino-L-alanine
L. Pinto da Silva 1 , M.S. Baptista 2 , R.C.C. Cianca 2,3 , C.M.R. Almeida 2 , V.M.
Vasconcelos 2,4
1 Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Portugal
2 CIMAR/CIIMAR, Centre of Marine and Environmental Research, University of Porto, Portugal
3 Department of Biology, Faculty of Biology, University of Vigo, spain
4 Department of Biology, Faculty of Sciences, University of Porto, Portugal
Nonproteinogenic amino acids are naturally occurring ones which are not genetically encoded
[1]. Amongst these, the amino acid β-N-methylamino-L-alanine (BMAA) is currently believed
to be produced by diverse species of cyanobateria [2]. Because of a possible role of BMAA as
a neurotoxin, several analytical techniques have been reported for the determination of this
amino acid [3]. Some of these works reported a previous sample derivatizion step [2].
However, these results have been challenged by more recent works without the derivatization
step [3].
In this work the optimization of a capillary electrophoresis (CE) method for BMAA
determination is described. This was achieved by assessing the limit of detection (LOD), linear
range, and applicability of the method for measuring BMAA in different cyanobacteria culture
media (f2, Z8, Z8 10 , MN) with different salinities. BMAA was determined using a fused-silica
capillary column (50 cm x 75 μm I.D.), with 5 mM sodium tetraborate solution, under the
applied voltage of 25 kV, at 25 ºC, with no sample processing or concentration.
One of the resulting peaks can be seen in Fig
1. Results indicate that CE appears to be a
highly adequate technique to measure
BMAA, given its specificity for amino acids
and the cheapness and readiness of the
analysis. The utility of the method can be
extended further to analysis coupled with
sample pre-extraction procedures.
References:
Fig.1: Electrophoregram obtained in a f2 culture media.
[1] Adamczyk, M., Akireddy, S.R. and Reddy, R.E. (2002), Nonproteinogenic amino acids: an efficient
asymmetric synthesis of (S)-(-)-acromelobic acid and (S)-(-)-acromelobinic acid, Tetrahedron, 58,
6951-6963.
[2] Banack, S.A., Johnson, H.E., Cheng, R. and Cox, P.A. (2007), Production of the neurotoxin BMAA
by a marine cyanobacterium, Mar. Drugs, 5, 180-196.
[3] Moura, S., Ultramari, M.A., Paula, D.M.L., Yonamine, M. and Pinto, E. (2009), 1 H NMR
determination of β-N-methylamino-L-alanine (L-BMAA) in environmental and biological samples,
Toxicon, 53, 578-583.
Acknowledgements: This work was partially funded by Fundação para a Ciência e a Tecnologia, Portugal,
(fellowship awarded to M. Baptista (SFRH/BD/44373/2008) and the CONC-REEQ/304/2001 re-equipment
project) and U.Porto/Santander Totta, Portugal, through the “Investigação Jovem na U. Porto” program.
324 3 rd meeting of young researchers at UP