Simultaneous Determination of Imazalil and Its Major Metabolite in Citrus Fruit by Solid-Phase Extraction and Capillary Gas Chromatography with Electron Capture Detection
Abstract A method was developed for the simultaneous determination of imazalil and its major metabolite, R 14821, in citrus fruit. This method (designated the SPE method) is based on solid-phase extraction (SPE) and capillary gas chromatography (GC) with electron-capture detection (ECD). The SPE method is highly sensitive for both compounds (limit of detection for each: 0.001 μg/g) and is less time consuming than the previously reported method based on repeated liquid–liquid partitioning and GC–ECD. Recoveries for 3 levels of fortification (0.02, 0.2, and 2.5 μg/g) from satsuma mandarins ranged from 94.3 to 96.5% for imazalil and from 93.9 to 96.3% for R 14821, with coefficients of variation (CVs) ranging from 3.1 to 6.3% for imazalil and from 4.5 to 5.6% for R 14821. Average residual levels found in grapefruit, oranges, and lemons by the SPE method and the previously reported method, and the corresponding CVs, were similar.