Highly Sensitive LC-MS/MS Method for Determination of Hymexazol Residues in Sugar Beet

Abstract

This study developed a detection method for hymexazol residues in sugar beet, targeting its low molecular weight, high polarity, and lack of chromophores. The method optimized mass spectrometry conditions, liquid chromatography parameters, and extraction/purification protocols to address the matrix characteristics of sugar beet. Specifically, the sample pretreatment involved extraction with acetonitrile, followed by purification using GCB, silica, and C18 sorbents to minimize matrix interference. Sensitivity was enhanced by reducing flow rate and spray voltage. The method demonstrated high performance and was applied to analyze real samples. The LOD and LOQ were theoretically determined to be 1.22 and 3.80 μg/kg, respectively, using the blank standard deviation method. At the spiked levels of 5.0, 10, and 50 μg/kg, the intraday and interday recoveries were 80.2–97.9% and 78.1–101.7%, with corresponding RSDs of 4.8–6.4% and 4.6–8.8%, respectively. These results could meet the requirements for pesticide residue analysis and regulatory monitoring.