Improving derivatization efficiency of BMAA utilizing AccQ-Tag in a complex cyanobacterial matrix.

Johan Eriksson, Sara Jonasson, Dimitra Papaefthimiou, Ulla Rasmussen, Birgitta Bergman

Index: Amino Acids 36 , 43-8, (2009)

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Abstract

Two different assays have been developed and used in order to investigate the optimal conditions for derivatization and detection of acid beta-N-methyl-amino-L-alanine (BMAA) in a cyanobacterial sample. BMAA was extracted from cyanobacterial cultures both from the cytosolic ("free") fraction and in the precipitated ("protein") fraction using a newly developed extraction scheme and the sample matrix was standardized according to protein concentration to ensure the highest possible derivative yield. A rapid and sensitive HPLC method for fluorescence detection of the non-protein amino acid BMAA in cyanobacteria, utilizing the Waters AccQ-Tag chemistry and Chromolith Performance RP-18e columns was developed. Using this new method and utilizing a different buffer system and column than that recommended by Waters, we decreased the time between injections by 75%. The limit of quantification was determined to be 12 nmol and limit of detection as 120 fmol. The linear range was in the range of 8.5 nmol-84 pmol. Accuracy and precision were well within FDA guidelines for bioanalysis.