Automation and miniaturization of solid-phase extraction for high-throughput analysis of cyanotoxins

We present a resource-efficient method for automated sample preparation, designated to facilitate high- throughput analysis of microcystins and nodularin-R. These cyanotoxins, commonly associated with harmful algal blooms, are monitored to ensure the safety of drinking water and recreational water bodies. The method utilizes a liquid handling platform to flexibly process between 1 and 96 samples within one hour for subsequent LC-MS analysis, requiring only 5 mL of sample for triplicate analysis. By miniaturizing solid-phase extraction into a 96-well format, the protocol reduces transfer volumes, and solvent consumption and has the potential to decrease the use of plastic materials. This approach is suitable for both high-throughput analyses and long-term monitoring studies, and it has been successfully applied to diverse water sources, including river, lake, pond, and HPLC-grade water. The method demonstrates excellent accuracy, with results meeting recommended guidelines. As proof of concept, it was applied to quantify cyanotoxins in two lake water samples and a laboratory culture of Microcystis aeruginosa.