Simultaneous determination of 19 mycotoxins in lotus seed using a multimycotoxin UFLC-MS/MS method

Objectives: In relevance to the internal components and improper environmental conditions, lotus seeds are susceptible to fungal contamination and mycotoxins residue, leading to harmful impacts on the quality and safety, as well as their pharmaceutical efficacy and clinical use. It is necessary and urgent to assess various mycotoxins residue in lotus seeds. This study aimed to develop a sensitive method for accurate assessment of multimycotoxin residues in lotus seeds.

Methods: A simple and reliable modified ultrasonication-assisted extraction, QuEChERS purification based ultrafast liquid chromatography tandem mass spectrometry (UFLC-MS/MS) method was successfully developed for ultrasensitive determination of 19 multiclass mycotoxins in starch-rich lotus seeds. Four extraction modes and three clean-up sorbents for improving the recoveries of mycotoxins were optimized. Limits of detection (LODs) and quantification, linearity, precision, accuracy, and matrix effect were studied for method validation. For simultaneous qualitation and quantification, the 19 chemically diversified mycotoxins were well separated on a CAPCELL CORE C18 column (100 mm × 2.1 mm, 2.7 μm) and detected in positive/negative electrospray ionization mode within 7 min.

Key findings: The validated method exhibited satisfactory linearity (r > 0.995), ultragood selectivity (LODs of 0.1-15.0 μg/kg), excellent precision (RSDs <13.0%) and convincing accuracy (recoveries between 79.4% and 131.6% with RSDs <14.4%). Matrix effect, between 54.5% and 113.6%, appeared especially for aflatoxins B₁ and B₂ , deoxynivalenol and T-2 toxins. Matrix-matched curve-based quantification showed that 26 (57.8%) out of 45 lotus seed samples were contaminated with one or more mycotoxins, and ochratoxin A, aflatoxin B₂ , aflatoxin B₁ and citrinin were the most prevalent mycotoxins.

Conclusions: This study reports for the first time the incidence of a wide range of 19 mycotoxins in lotus seeds and the proposed method will get broad application for more trace components in other complex matrices.