Calibration curves of three of the ELISA plates used in this study.

<p>Calibration standards provided with the kit are shown in black circles and solid black lines, calibration standards in water are shown in white circles and dotted black lines and calibration standards in sample diluent are shown in grey circles and grey solid lines. Outliers that are omitted from the calibration curve are shown as black crosses, all outliers belong to the standards from the kit.</p

BMAA concentrations (µg/l) in untreated and filtered samples as determined by ELISA.

*<p>1 replicate not detected,</p>**<p>2 replicates not detected.</p

Chromatograms of the three analytical methods showing calibration standards and an extracted cyanobacterial sample.

<p>Panels A–C show calibration standards, panels D–F show the extracted <i>Anabaena</i> field scum. The green line in panel D represents the unspiked cyanobacterial sample, the blue line indicates the same sample, but spiked with BMAA before extraction. Colored lines in panels B and E represent the transitions of ions with a mass-to-charge ratio (<i>m/z</i>) of 459 to <i>m/z</i> 171 (blue), 119 (green), 145 (pink) and 315 (orange). Colored lines in panels C and F represent the transitions of <i>m/z</i> 119.1 to <i>m/z</i> 102.1 (blue), 88 (pink), 76 (green), 101 (gray) and 74 (orange). Transitions for D₃BMAA are not shown.</p

Sample origin, pre-treatment and storage conditions.

<p>n.a.: not applicable.</p

BMAA concentration by ELISA and LOD^* (both expressed as µg/g DW) for unspiked hydrolysates of sample 11 in two different solvents.

*<p>LOD: limit of detection, n.d.: not detected.</p

Recovery (%) of extraction and hydrolysis, analyzed by the three different methods.

a<p>recovery is calculated for D₃BMAA.</p

Overview of studies that analyzed more than eight samples of free living cyanobacteria for BMAA.

a<p>BMAA concentration is the sum of the free and protein associated concentrations. Values are averages, followed by minimum and maximum concentrations between brackets.</p

Validation results of the three used methods, both LC-MS/MS methods are validated without correction for the internal standard D₃BMAA.

<p>LOD: limit of detection, LOQ: limit of quantification, RT: retention time,</p>a<p>each concentration is injected in triplicate,</p>b<p>n = 11,</p>*<p>not determined (see text).</p

BMAA concentration as determined by ELISA and LOD^* (both expressed as µg/g DW) for unspiked extracts of sample 11 in two different solvents.

*<p>LOD: limit of detection, n.a.: not analysed, sample pH too low, a.c.: above calibration curve (equivalent to >300 µg/g BMAA in sample), n.d.: not detected.</p

Recovery of spiked samples without cyanobacterial blooms.

<p><b>Error bars represent one SD, n = 3.</b></p