The present work deals with the development of analytical methods for monitoring pesticide
residues in food, which is of paramount importance to ensure compliance with permitted
maximum limits and safeguard human health. However, the monitoring of pesticide residues in
surface waters has been less explored due to various challenges. The presence of interferents
and low analyte concentrations necessitates the development of increasingly sensitive and
selective analytical techniques. The QuEChERS method, a solid-phase extraction (s-SPE)
technique commonly used for sample preparation, has been extensively applied in food matrices
but is less utilized in liquid matrices. The application of methods for analyzing water inputs is
crucial for environmental control and human health preservation. This study focuses on
optimizing chromatographic conditions for the determination of the pesticide Ametryn by GC-
MS in SCAN mode. Initially, the conditions resulted in excessive noise, leading to adjustments
that brought about significant improvements. Switching to the SIM mode increased selectivity
and sensitivity, highlighting Ametryn. Method validation confirmed linearity, with a calibration
curve in both solvent and matrix, demonstrating good linearity. Matrix effects were analyzed,
revealing a considerable influence on signal intensity. Statistical tests confirmed the
significance of linear regression and calibration parameters. Detection and quantification limits
were determined, showing higher sensitivity in the matrix. Precision was assessed through
repeatability using the CV%, and accuracy was evaluated through recovery tests, demonstrating
results within acceptable limits. The method applied to real water samples did not reveal
Ametryn residues but identified the compound 2,4-Di-tert-butylphenol, possibly a byproduct of
the degradation of the organochlorine herbicide Pentachlorophenol. This study contributes to
the development of efficient analytical methods for pesticide detection, addressing crucial
aspects such as selectivity, linearity, and matrix effects, while also providing relevant
information on degradation byproducts.
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