Multiclass cyanotoxin analysis in reservoir waters: Tandem solid-phase extraction followed by zwitterionic hydrophilic interaction liquid chromatography-mass spectrometry

Abstract

The presence of cyanobacteria and cyanotoxins in all water bodies, including ocean water and fresh water sources, represents a risk for human health as eutrophication and climate change are enhancing their level of proliferation. For risk assessment and studies on occurrence, the development of reliable and sensitive analytical approaches able to cover a wide range of cyanotoxins is essential. This work describes the development of an HILIC-MS/MS multiclass method for the simultaneous analysis of eight cyanotoxins in reservoir water samples belonging to three different classes according to their chemical structure: cyclic peptides (microcystin-LR, microcystin-RR and nodularin), alkaloids (cylindrospermopsin, anatoxin-a) and three non-protein amino acids isomers such as β-methylamino-L-alanine, 2,4diaminobutyric acid and N-(2-aminoethyl)glycine). A SeQuant ZIC-HILIC column was employed to achieve the chromatographic separation in less than 12 min. Previously, a novel sample treatment based on a tandem solid-phase extraction (SPE) system using mixed cation exchange (MCX) and Strata-X cartridges was investigated with the aim of extracting and preconcentrating this chemically diverse group of cyanotoxins. The Strata-X cartridge, which was configured first in the line of sample flow, retained the low polar compounds and the MCX cartridge, which was at the bottom of the dual system, retained mainly the non-protein amino acids. The optimization procedure highlighted the importance of sample ion content for the recoveries of some analytes such as the isomers β-Nmethylamino-L-alanine and 2-4diaminobutyric acid. Method validation was carried out in terms of linearity, limit of detection (LOD) and quantification (LOQ), recoveries, matrix effect and precision in terms of repeatability and intermediate precision. This work represents the first analytical method for the simultaneous analysis of these multiclass cyanotoxins in reservoir water samples, achieving LOQs in the very low range of 7•10 -3 -0.1 µg•L -1 . Despite high recoveries obtained at the LOQ concentration levels (101.0-70.9%), relative standard deviations lower than 17.5% were achieved.

Determination of Multiclass Cyanotoxins in Blue-Green Algae (BGA) Dietary Supplements Using Hydrophilic Interaction Liquid Chromatography-Tandem Mass Spectrometry

“…The chromatographic separation and MS/MS detection conditions employed were based on our previous work for the analysis of these toxins in reservoir water samples [ 34 ]. At this initial study, different stationary phases were tested; reversed phase (RP) columns (Zorbax RRHD Eclipse Plus C18, Luna Omega C18 Polar and Kinetex Biphenyl) and HILIC columns (Kinetex HILIC and SeQuant ZIC-HILIC).…”

“…After centrifuging at 9000 rpm and 4 °C during 10 min, the supernatant was transferred to a 50 mL centrifuge tube and made up to 32 mL with deionized water to achieve a 10% organic solvent (MeOH) in the extract for loading onto tandem-SPE. The aqueous extract was submitted to the tandem-SPE procedure previously described in [ 34 ]. Among all the tested solvents, 80% MeOH showed the best results with recoveries above 70% for MCs and NOD, and about 60% for ANA ( Figure 2 A).…”

“…In a previous work, we established an UHPLC-MS/MS method for the simultaneous determination of different classes of cyanotoxins in reservoir waters. A tandem-SPE procedure was employed to extract and preconcentrate the analytes [ 34 ]. Based on the progress achieved in such work, the main goal of this study is to propose an effective analytical method for comprehensive determination of the free fraction of seven cyanotoxins, belonging to the cyclic peptide family (MC-LR, MC-RR and NOD) [ 35 ], alkaloid family (ANA) [ 36 ], and NPAs (BMAA, DAB and AEG) [ 37 ], from BGA and microalgae-derived dietary supplements.…”

Ultrasensitive Aptasensor for Microcystin-LR Detection in Food Samples Based on Target-Activated Assembly of Y-Shaped Hairpin Probes

“…Traditional techniques for MC-LR detection focused on high performance liquid chromatography (HPLC) and liquid chromatography−mass spectrometry (LC−MS). 7,8 Although they are sensitive and accurate, these methods require bulky and expensive instruments, complicated operation steps, and well-trained technicians. 9 Using aptamer as the molecular recognition element to construct aptasensor for target detection can provide an effective way to address the abovementioned limitations.…”

“…Traditional techniques for MC-LR detection focused on high performance liquid chromatography (HPLC) and liquid chromatography–mass spectrometry (LC–MS). , Although they are sensitive and accurate, these methods require bulky and expensive instruments, complicated operation steps, and well-trained technicians . Using aptamer as the molecular recognition element to construct aptasensor for target detection can provide an effective way to address the above-mentioned limitations. − Some elegant sensing strategies have been proposed for MC-LR detection, such as electrochemical detectors, colorimetric assay, fluorescence sensors, and Raman scattering technology. − For example, Wang and co-workers have designed gold nanoparticles protected aptamer for MC-LR detection based on deoxyribonuclease cleavage reaction .…”