title: Quantitative determination of the neurotoxin β-N-methylamino-L-alanine (BMAA) by capillary electrophoresis-tandem mass spectrometry.
abstract: Recent reports of the widespread occurrence of the neurotoxin β-N-methylamino-L-alanine (BMAA) in cyanobacteria and particularly seafood have raised concerns for public health. LC-MS/MS is currently the analytical method of choice for BMAA determinations but incomplete separation of isomeric and isobaric compounds, matrix suppression and conjugated forms are plausible limitations. In this study, capillary electrophoresis (CE) coupled with MS/MS has been developed as an alternative method for the quantitative determination of free BMAA. Using a bare fused silica capillary, a phosphate buffer (250 mM, pH 3.0) and UV detection, it was possible to separate BMAA from four isomers, but the limit of detection (LOD) of 0.25 μg mL-1proved insufficient for analysis of typical samples. Coupling the CE to a triple quadrupole MS was accomplished using a custom sheath-flow interface. The best separation was achieved with a 5 M formic acid in water/acetonitrile (9:1) background electrolyte. Strong acid hydrolysis of lyophilized samples was used to release BMAA from conjugated forms. Field-amplified stacking after injection was achieved by lowering sample ionic strength with a cation-exchange cleanup procedure. Quantitation was accomplished using isotope dilution with deuterium-labelled BMAA as internal standard. An LOD for BMAA in solution of 0.8 ng mL-1was attained, which was equivalent to 16 ng g-1dry mass in samples using the specified extraction procedure. This was comparable with LC-MS/MS methods. The method displayed excellent resolution of amino acid isomers and had no interference from matrix components. The presence of BMAA in cycad, mussel and lobster samples was confirmed by CE-MS/MS, but not in an in-house cyanobacterial reference material, with quantitative results agreeing with those from LC-MS/MS. Graphical Abstract CE-MS separation and detection of BMAA, its isomers and the internal standard BMAA-d3.
authors.affiliation: National Research Council Canada, Measurement Science and Standards, 1411 Oxford Street, Halifax, Nova Scotia, B3H 3Z1, Canada.|Department of Chemistry, Dalhousie University, 6274 Coburg Road, P.O. Box 15000, Halifax, Nova Scotia, B3H 4R2, Canada.
authors.forename: Elliott S
authors.initials: ES
authors.lastname: Kerrin
authors.affiliation: Department of Chemistry, Dalhousie University, 6274 Coburg Road, P.O. Box 15000, Halifax, Nova Scotia, B3H 4R2, Canada.
authors.forename: Robert L
authors.initials: RL
authors.lastname: White
authors.affiliation: National Research Council Canada, Measurement Science and Standards, 1411 Oxford Street, Halifax, Nova Scotia, B3H 3Z1, Canada. michael.quilliam@nrc.ca.|Department of Chemistry, Dalhousie University, 6274 Coburg Road, P.O. Box 15000, Halifax, Nova Scotia, B3H 4R2, Canada. michael.quilliam@nrc.ca.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Quilliam
mesh_terms: D000599:Amino Acids, Diamino / Q000032:analysis*; D000818:Animals; D049872:Bivalvia / Q000737:chemistry; D000458:Cyanobacteria / Q000737:chemistry; D000087522:Cyanobacteria Toxins; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D005506:Food Contamination / Q000032:analysis*; D057230:Limit of Detection; D008121:Nephropidae / Q000737:chemistry; D009498:Neurotoxins / Q000032:analysis*; D012758:Shellfish / Q000032:analysis*; D053719:Tandem Mass Spectrometry / Q000295:instrumentation / Q000379:methods*
chemical_list: D000599:Amino Acids, Diamino; D000087522:Cyanobacteria Toxins; D009498:Neurotoxins; C001824:beta-N-methylamino-L-alanine
keywords: BMAA; Capillary electrophoresis; Mass spectrometry; Neurotoxin; Shellfish; β-N-Methylamino-L-alanine