Interlaboratory comparison trial on cylindrospermopsin measurement.

The hepatotoxin cylindrospermopsin (CYN) is a potent inhibitor of protein synthesis in mammalian cells. It is produced by freshwater cyanobacterial blooms in countries such as Australia, the United States, Israel, Thailand, and Brazil. An interlaboratory comparison was organized as a first step to evaluate the measurement of CYN in lyophilized cyanobacterial cells. Six laboratories from Europe, Israel, and Australia participated in the trial. All of the methods used for extraction of the toxin and the high-performance liquid chromatography (HPLC) analysis were satisfactory on the basis of statistical evaluation, according to ISO standards 5725-1 and -2. Further comparison of all the extraction methods by the organizer indicated that the most effective extraction procedure used 5% formic acid to prevent interference in chromatograms by contaminant compounds when analyzed using HPLC employing isocratic conditions of 5% (v/v) aqueous methanol plus 0.1% (v/v) trifluoroacetic acid as the mobile phase.

HPLC-PDA detection of cylindrospermopsin--opportunities and limits.

The cyanobacterial hepatotoxic alkaloid cylindrospermopsin (CYL) is of increased concern to public health due to the spreading of its main producer, Cylindrospermopsis raciborskii, around the globe. Here we present results of an evaluation of the possibility to analyse environmental samples for their content of CYL based on HPLC with photo diode array detection as an alternative to costly LC-MS approaches. A gradient from 0% to 50% aqueous methanol (+0.05% trifluoroacetic acid) in 20 min proved to be highly reproducible with respect to peak height, peak area, and retention time of purified CYL. Good linearity of peak area response was found for 1-300 ng CYL on column. For a good performance the duration of equilibration prior to individual runs was crucial. Extraction from cell material (culture and bloom) was efficiently done with pure water in one extraction step and CYL contents determined matched well with results previously obtained by LC-MS. When different seston matrices were added to cultured cells to mimic realistic environmental samples, however, peaks eluting close to CYL in chromatograms restrained the performance. The data presented show a limitation of HPLC-PDA analysis for trace amounts of CYL in environmental samples but also underline the potential of an inexpensive and fast analysis for various purposes.