Ionic-liquid-functionalized zinc oxide nanoparticles for the solid-phase extraction of triazine herbicides in corn prior to high-performance liquid chromatography analysis

Zinc oxide nanoparticles have recently been used as effective adsorbent materials for sample pretreatment in analytical chemistry because of their excellent properties, such as high specific surface area, high effective porosity, non-toxicity, and ease of fabrication. In this study, the zinc oxide nanoparticles functionalized by an ionic liquid, 1-carboxyethyl-3-methylimidazolium chloride, were fabricated and used as the adsorbent for the solid phase extraction of five triazine herbicides in corn for the first time. High-performance liquid chromatography was employed for the determination of these triazine herbicides. Several experimental parameters affecting the extraction efficiency were investigated, including the volume of extraction solvent, the extraction time, the type of extraction solvent and elution solvent, the amount of absorbent, and the volume of elution solvent. By using the proposed method, low limits of detection and quantification for all the five triazine herbicides were obtained between 0.71–1.08 and 2.67–3.64 ng/g, respectively. Recoveries of the proposed method range from 89.05 to 100.33% with intra- and inter-day relative standard deviations lower than 8.45%. The calibration curves are linear in the concentration range of 0.005–1.00 μg/g with the correlation coefficient higher than 0.9954.