# Determination of Cyanotoxins and Prymnesins in Water, Fish Tissue, and Other Matrices: A Review
###### Abstract  
Harmful algal blooms (HABs) and their toxins are a significant and continuing threat to aquatic life in freshwater, estuarine, and coastal water ecosystems. Scientific understanding of the impacts of HABs on aquatic ecosystems has been hampered, in part, by limitations in the methodologies to measure cyanotoxins in complex matrices. This literature review discusses the methodologies currently used to measure the most commonly found freshwater cyanotoxins and prymnesins in various matrices and to assess their advantages and limitations. Identifying and quantifying cyanotoxins in surface waters, fish tissue, organs, and other matrices are crucial for risk assessment and for ensuring quality of food and water for consumption and recreational uses. This paper also summarizes currently available tissue extraction, preparation, and detection methods mentioned in previous studies that have quantified toxins in complex matrices. The structural diversity and complexity of many cyanobacterial and algal metabolites further impede accurate quantitation and structural confirmation for various cyanotoxins. Liquid chromatography-triple quadrupole mass spectrometer (LC-MS/MS) to enhance the sensitivity and selectivity of toxin analysis has become an essential tool for cyanotoxin detection and can potentially be used for the concurrent analysis of multiple toxins. harmful algal blooms; cyanotoxins; cyanobacteria; fish tissue; shellfish; detection methods  
13 March 20221316 March 202213 March 202216 March 202213 cylindrospermopsins (_Oscillatoria_ and _Raphidiopsis_), Lyngbyatoxin-a (_Lyngbya_), saxitoxins (_Anubuena_, _Aphanizomenon_, _Cylindrospermum_, _Lyngbya_, _Phormidium_, and _Raphidiopsis_), and aplysiatoxins (_Lyngbya_, _Schizoltrix_, and _Oscillatoria_) [1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 11]. Microcystins (MCs) are the most frequently studied and the most widespread cyanotoxins [12], with approximately 50% of publications on cyanotoxins focusing on MCs, 25% on saxitoxins, and 25% on other toxins (such as nodularin, anatoxin-a, \(\beta\)-N-methylamino-L-alanine, cylindrospermopsins, and prymnesins). Of these publications, a majority focus on detection in water matrices. There is limited information on the presence of MCs and other cyanotoxins in matrices such as aquatic food webs, phytoplankton, zooplankton, periphyton, macroinvertebrates, forage fish, bottom feeders, and top carnivore fish. Since research on cyanotoxins has mostly focused on MCs, especially in water matrices, the development and standardization of better monitoring methods for other cyanotoxins and complex matrices, such as those mentioned above, are of utmost importance. Various techniques have been developed to analyze cyanotoxins in water. These methods include enzyme-linked immunosorbent assay (ELISA), protein phosphatase inhibition assay (PPIA), oxidation of MCs to produce erythro-2-methyl-3-methoxy-4-phenylbutyric acid (MMPB) [13], and chromatography coupled with various detection methods [14]. A survey of chromatographic methods for the detection of cyanotoxins in water could be divided into the following main categories: liquid chromatography with ultraviolet detection (LC-UV), LC with fluorescence detection (LC-FLD), LC-photo-diode array (LC-PDA) or similar, LC with tandem mass spectrometry (LC-MS/MS), gas chromatography with mass spectrometry (GC-MS), ion mobility spectrometry (IMS), and immunological assays. LC-MS, or single quadrupole mass spectrometry, has largely been replaced by LC-MS/MS. Among these methods, a few LC-MS/MS and ELISA-based standard methods developed by the U.S. Environmental Protection Agency (EPA) and the International Organization for Standardization (ISO) are available, are considered standard, are widely used for the measurement of cyanotoxins in water, and can potentially be adapted for use with other matrices, such as fish tissue [15; 16; 17; 18]. However, there is no standardized analytical method to detect these cyanotoxins in other matrices [19].