Simultaneous determination of twelve microcystins in algal supplements on the Chinese market and possible risks to exposed populations.

Algae supplements are widely recognized for their nutritional benefits and are commonly marketed as natural health products. However, concerns regarding contamination with cyanobacterial toxins have been raised. Moreover, there is very little data regarding the potential contamination of algal supplements on the Chinese market by these toxins. In this study, we employed a validated solid-phase extraction ultra-high-performance liquid chromatography-tandem mass spectrometry (SPE-UHPLC-MS/MS) method to analyze algal supplements available in China. Therefore, this study optimized the extraction conditions for twelve microcystins (MCs) simultaneously using response surface methodology (RSM) and analyzed via UHPLC-MS/MS. Method validation was conducted in four supplement matrices (capsule, liquid, powder, and tablet) to ensure the method's accuracy, sensitivity, and reproducibility. Analysis of nineteen commercial algae products available in China using the validated method revealed the presence of four MCs: microcystin-LF (MC-LF), microcystin-LR (MC-LR), microcystin-LA (MC-LA), and microcystin-YR (MC-YR). Furthermore, seven products were found to contain one or more of the MCs, with two products exceeding the 1 μg/g MC limit. These findings underscore the effectiveness of the validated method in assessing MC contamination of algae supplements and consequently identifying consumers expected to be at risk from prolonged exposure to recommended daily algal supplements.