Direct monitoring of pesticide residues by DART-MS: From river water to fish scales.

This study demonstrates the feasibility of direct analysis in real-time mass spectrometry (DART-MS) for rapid pesticide residues screening in aquatic ecosystems, highlighting the application of fish scales as a non-lethal biological matrix. For this purpose, multivariate approaches were employed to optimize the significant variables of the DART-MS method. The optimal conditions included a grid voltage of 150 V, a gas temperature of 200 °C, and the distance between the source and the mass spectrometer inlet of 3.2 cm. The DART-MS method demonstrated excellent performance for determination of ten pesticides in river water, achieving limits of quantification of 10 ng mL-1 and outstanding precision and accuracy. In addition, the quantitative performance of the DART-MS approach was evaluated for atrazine determination in fish plasma, showcasing its applicability to complex biological matrices following a simple sample preparation procedure. In addition, the direct analysis of fish scales enabled the rapid detection of pesticides without prior sample preparation. Overall, this proof-of-concept study demonstrates the applicability of DART-MS for pesticide monitoring in complementary aquatic matrices, including river water, plasma, and fish scales, while establishing fish scales as a promising matrix for environmental screening.