Miniaturized UAE-SPE-d-SPE-HPLC-UV method for trace determination of triazine herbicides in corn tortillas

An analytical methodology was developed for simultaneous extraction and determination of triazine herbicides atrazine and simazine in maize tortillas. This method combined ultrasound-assisted extraction (UAE) using a methanol:water mixture followed by simple and rapid miniaturized solid-phase extraction-dispersive solid-phase extraction (SPE-d-SPE) concentration and a clean-up step using C18/PS-DVB sorbents. Only 100 μL of the extract was obtained through effective matrix simplification. This allowed determination of herbicides using HPLC-UV with good linearity (R² > 0.99) (range of 50-250 ng g^-1) and limits of detection and quantification in the ranges of 20-50 and 20-60 ng g^-1 for atrazine and simazine, respectively, enabling monitoring at the maximum residue limit (MRL) established for maize (250 ng g^-1). Precision was less than 7.5%, and recoveries were 71% for simazine and 76% for atrazine. The proposed method proved robust across tortillas prepared from maize of different varieties and origins in Mexico. This approach provides a reliable and miniaturized tool for trace-level determination of triazine herbicides, supporting food safety monitoring of maize-based products.