Background: Cyanobacteria are a widely distributed group of photosynthetic prokaryotes and are considered relevant contributors for the formation of the Earth’s atmosphere. Many of them produce toxins as secondary metabolites (cyanotoxins) that include a wide range of hepatotoxins (microcystins, nodularin, cilindrospermopsin), neurotoxins (anatoxins, saxitoxins and β- metilamino-L-alanine) and dermatotoxins (lyngbyatoxins, aplysyatoxin). In recent years, the occurrence of harmful cyanobacteria blooms (CyanoHABs) related to human-driven environmental factors has dramatically increased becoming a growing concern for the environment and public health. Despite the many applications used in routine investigations, cyanotoxins analysis remains challenging due to the number and diverse compounds involved. Several innovative methods based on biological and physico-chemical approaches are being developed to identify and quantify the toxins as well as the responsible harmful strains.
Objective: Chromatographic methods with their separation capabilities are a powerful investigation tool, despite the huge number of molecules that need to be determined for many toxin types. HPLC is the most widely used separation method for cyanotoxins; it is highly sensitive, rapid and adaptable to a wide range of detectors based on UV absorbance, fluorescence or mass spectrometry. On the other hand, gas chromatography has been scarcely applied for toxin determination due to the requirement of high molecular weight molecules and the need for derivatization. Even more articles and applications are being published: the objective of this review is to give a synthetic and comprehensive view of the separation methods used in this field and their advances in the past years.
Method: Chromatographic methods have been reviewed from 1990-2000 to 2017, with special attention to multitoxin applications, including additional techniques like MALDI-TOF mass spectrometry and capillary electrophoresis.
Results: In this paper, a review of different chromatographic applications for cyanotoxins analysis is presented together with the sample preparation methods most widely used. Multitoxin applications are highlighted. Especial attention is given to the most recent advances in HPLC-MS, HPLC tandem-MS and high resolution MS techniques. Some capillary electrophoresis applications are described as well.
Conclusion: Recent advances in chromatography include liquid chromatography and/or mass spectrometric investigations for characterization and determination in lake and river waters of different cyanobacterial toxins (microcystins, anatoxin-A, PSP toxins and related metabolites) simultaneously and new molecules like oligopeptides and novel secondary metabolites (anabaenopeptins, aeruginosins, microginins, microviridins and cyanopeptolins).