Residue Analysis of Fungicide Boscalid in Cucumbers Following Applications of Boscalid 50% Water Dispersible Granule
Miao-Fan Chen1,2, Jenn-Wen Huang1* and Hsiu-Pao Chien2
1. Department of Plant Pathology, National Chung Hsing University, Taichung 402, Taiwan, R.O.C.
2. Division of Residue Control, Taiwan Agricultural Chemicals and Toxic Substances Research Institute,
Council of Agriculture, Taichung 413, Taiwan, R.O.C.
(Received: September 11, 2006; Accepted: December 27, 2006)
Abstract
This study determined the residue of fungicide boscalid in/on cucumbers following three applications of boscalid 50% water dispersible granule (WG). The fungicide was applied to cucumbers at two rates, 0.5 and 0.83 kg a.i./ha. Samples were collected at 0, 1, 2, 3, 4, 6, 7, 10, 12, 15, 18, and 21 d after the last application. The sample was extracted with methanol/H2O/2 N HCl (70:25:5, v/v) and n-hexane and subject to GC analysis. Residues of boscalid were determined by GC/µ-ECD with DB-5 capillary column. Recoveries of boscalid in/on cucumbers ranged from 86.0 to 103.6% and the relative standard deviation (RSD) ranged from 1.2 to 4.8%. The limit of quantification was 0.01 µg/mL (S/N>10). This analytical method was applied to study the dissipation of boscalid in/on cucumbers. The results indicated that the residues of boscalid were declined in/on cucumbers with time. Only 5 and 17% of the initial deposits were found in/on the cucumbers 6 d after the last application at the low and high dose, respectively.
Key words: boscalid, residue, analysis, cucumber, dissipation