Combining QuEChERS and multi-dimensional liquid chromatography for the analysis of fungicides in produce Items

Abstract

<p><span>The broad term &lsquo;pesticide&rsquo; encompasses a variety of chemicals belonging to subcategories including insecticides, herbicides, and fungicides.¹ The latter, fungicides, is the type of pesticide studied in this thesis research. Despite the beneficial properties of pesticides for regulating crop pests, they have also been shown to threaten the health of human organs and systems.² The health concerns of pesticides are widespread and can be both acute and chronic.² Acute health effects include irritation and burning of the skin, mouth or nose, and more urgent responses such as impaired cognition and seizures.¹ Potential chronic repercussions include detriment to reproductive, pulmonary, and neurological health.¹ In recent years, pyrimethanil (PYRI), fludioxonil (FLU), boscalid (BOS), and pyraclostrobin (PYRA) were commonly detected in produce items by the Environmental Working Group (EWG).² </span></p> <p><span>This research focuses on developing a two-dimensional liquid chromatographic (2D-LC) method for the separation, detection, and quantification of PYRI, FLU, BOS and PYRA in produce items. With this goal in mind, a 2D-LC heart-cutting method was developed, which produced properly resolved, symmetrical and sharp peaks in both separation dimensions. Interday coefficients of variation (CV) for retention times and peak areas ranged from 0.093% &ndash; 7.352 % in both dimensions. A modified Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) clean-up procedure was employed for the clean-up of produce samples.⁵ Second dimension (2D) recoveries were determined to range from 51.3% &plusmn; 1.4% to 75.3% &plusmn; 2.1% for all analytes. Internal standard calibration was completed for all fungicides using phenanthrene as the internal standard. The coefficient of determination (R²) for all four calibration curves ranged from 0.990 &ndash; 0.992. For ²D analysis, the limits of detection (LOD) ranged from 0.043 &ndash; 0.131 mg/mL, while the limits of quantification (LOQ) ranged from 0.143 &ndash; 0.436 mg/mL. Using the optimized method, a Nova Scotian and a Peruvian blueberry sample were analyzed.</span></p>