A shotgun method for high throughput screening microcystins in Margarya melanioides on a triple quadrupole tandem mass spectrometry

A selective and sensitive procedure for determining seven hazardous microcystins in Margarya melanioides, using tandem mass spectrometry, is presented. The product ion m/z 135.2 was selected as representative for precursor ion scanning and used to increase overall sensitivity of this shotgun method. The method was validated, and recoveries ranged from 69.3 to 87.9%, with the relative standard deviation less than 10%. Limits of detection and quantitation were less than 3.1 and 9.3 ng·mL^-1, respectively. A total of 60 samples were tested using this method. 38 samples were found to be contaminated with microcystins, among which there are 31 samples whose estimated daily intake (EDI) was 0-7.8 times higher than the tolerable daily intake (TDI). This method would be useful for carrying out direct, ultra-rapid quantification of microcystins in foods, and is of significant interest for environmental and food safety applications.