Simultaneous determination of mycotoxins and pesticides by UHPLC-HRMS in aquaculture feed from intensive farms

Intensive aquaculture in southern Spain is growing, leading to increased use of plant-based ingredients in fish feed. While this shift results in more nutritionally balanced feeds, it also introduces the risk of contaminants like mycotoxins and pesticides, which can negatively affect feed production, fish health, and pose potential risks to consumers. However, studies on these contaminants in aquaculture feed are limited. In this study, a multiclass method was developed to determine 27 mycotoxins and 11 pesticides in aquaculture feed by ultrahigh performance liquid chromatography coupled with high resolution mass spectrometry (UHPLC-HRMS). The method involved a previous ultrasound-assisted solid-liquid extraction using an acidified mixture of acetonitrile and water, followed by a dispersive solid-phase extraction with MgSO 4 and C 18 . Characterization of the method was satisfactory for almost all compounds, with recovery values between 70 and 120 % and relative standard deviations (RSDs) below 20 %. The quantification limits were comparable to those reported in studies focusing on a single family of compounds. The method was applied to the analysis of aquaculture feeds with diverse compositions, revealing a high incidence of the mycotoxins enniatins, as well as the pesticides tebuconazole and pirimiphos methyl. The possible source of these contaminants and residues was investigated by analysing the main raw materials of the feeds, attempting to link their origin with the wheat and soy. Additionally, non-targeted analysis identified six additional pesticides, and one pesticide adjuvant not included in the targeted analysis, highlighting the importance of such studies. • Monitoring is crucial to ensure fish health, consumer safety & sustainability. • UHPLC-HRMS method development to detect 27 mycotoxins & 11 pesticides in fish feed. • High occurrence of mycotoxins (enniatins) & pesticides (pirimiphos methyl) found. • Non-targeted analysis revealed 6 additional pesticides & 1 pesticide adjuvant. • Raw ingredients (wheat, soy) were main contamination sources in aquafeeds.