Abstract
<jats:p>The extensive use of broad-spectrum systemic herbicides for crop protection, particularly highly polar pesticides, has led to increasing inputs of pesticide residues into aquatic environments worldwide. Over recent decades, pesticide development has shifted toward compounds that are generally more polar, less persistent, and considered to have reduced environmental impacts. However, this class of pesticides remains a major analytical challenge in environmental matrices due to their physicochemical properties, including high polarity and water solubility, strong chelating behavior, and the absence of chromophoric or fluorophoric functional groups. This study presents an optimized and validated method for the simultaneous determination of glufosinate (Glu), glyphosate (Gly), its primary metabolite aminomethylphosphonic acid (AMPA), amitrole, and ethephon at µg/L levels in water samples. Analysis was performed using ultrahigh-performance liquid chromatography–high-resolution mass spectrometry (UHPLC-HRMS) following sample pretreatment with OnGuard™ II RP cartridges to remove hydrophobic interferences. Chromatographic and mass spectrometric acquisition parameters were systematically optimized to ensure adequate separation and sensitivity. The method showed satisfactory linearity over the concentration range of 1–10 µg/L. Limits of detection (LOD) and quantification were 0.003 and 0.01 µg/L for Gly and AMPA, 0.009 and 0.03 µg/L for Glu, and 0.006 and 0.02 µg/L for amitrole and ethephon. Mean recoveries from spiked water samples ranged between 88% and 126%, demonstrating acceptable accuracy for environmental analysis. The validated method was successfully applied to the determination of polar pesticides in surface water samples collected from agricultural areas, confirming its suitability for routine environmental monitoring of trace-level contamination.</jats:p>