- Acknowledgements: This study was supported by Research Project PID2021-1278040B-I00 funded by Spanish MCIN/ AEI /10.13039/501100011033 and by “ERDF A way of making Europe” and PROYEXCEL_00195 funded by Consejería de Universidad, Investigación e Innovación, Junta de Andalucía. RCM thanks to the predoctoral contract from Project PID2021-1278040B-I00. Funding for open access charge: University of Granada / CBUA. The authors gratefully also acknowledge John Ray for English revision.
- Authors: R. Carmona-Molero, M.M. Aparicio-Muriana, F.J. Lara, A.M. García-Campaña, M. del Olmo-Iruela.
- Reference: Journal of Chromatography A 1717 (2024) 464666.
Cyanotoxins constitute a group of toxic secondary metabolites, the presence of which in any water body poses a major health risk. Moreover, advanced organisms such as edible plants exposed to these toxins, are a possible pathway for human exposure. Green analytical chemistry is demanding environmentally friendly analytical techniques. In this sense, we propose the use of capillary electrophoresis coupled to tandem mass spectrometry (CE-MS/MS) to determine a mixture of eight cyanotoxins belonging to three different classes: cyclic peptides (microcystin-LR, microcystin-RR and nodularin), alkaloids (cylindrospermopsin and anatoxin-a) and three isomeric non-protein amino acids (β-methylamino-l-alanine, 2,4-diaminobutyric acid and N-(2-aminoethyl)glycine). Separation was achieved by using an acidic background electrolyte consisting of 2 M formic acid and 20% acetonitrile in water. Parameters affecting MS/MS detection and the sheath-liquid interface were also studied. Finally, a combination of pH-junction, field-amplified sample stacking (FASS) and acid barrage as online preconcentration strategies, was employed to improve sensitivity and efficiency. The online preconcentration applied, in combination with a dual cartridge solid-phase extraction (SPE) system, allows to obtain limits of detection in the very low range of µg·L−1 for these multiclass cyanotoxins in reservoir water samples (from 0.005 to 0.10 µg·L−1). Furthermore, for the first time cyanotoxins are analysed in spinach samples through CE-MS/MS using the same SPE procedure, following lyophilisation and solid-liquid extraction with 6 mL 80 % aqueous MeOH.
