殺菌劑亞托敏在包葉菜及小葉菜之殘留消退分析

Dissipation of the fungicide azoxystrobin in Brassica vegetables

"本研究依據亞托敏殺菌劑在田間推薦之施藥方法，進行其在包葉菜及小葉菜之殘留消退分析。針對包心白菜（Brassica pekinensis Rupr.）及芥籃菜（B. alboglabra），分別噴灑2次23%亞托敏水懸劑。依序於最後一次施藥後之0、3、6、9、12、15、18及21天採樣，樣品經腈甲烷:水（9/1, v/v）及silica淨化管之淨化後，以液相層析儀附255 nm波長之紫外光偵測器進行殘量分析。偵測界限可達0.02 mg/kg。亞托敏於包心白菜及芥藍菜之回收率分別為84.9%及86.1%。農藥殘留分析結果，發現包心白菜中之亞托敏殘留量於當天為4.10 mg/kg，於施藥後18天，有0.63 mg/kg之殘留；而在芥藍菜之殘留量於當天為13.21 mg/kg，但施藥後9天，亞托敏之殘留量已降至0.10 mg/kg。目前訂定亞托敏在葉菜類之容許量為2 mg/kg（包葉菜）及1 mg/kg（小葉菜），因此建議其安全採收期分別為15天（包葉菜）及10天（小葉菜）。"

"Residues of the fungicide azoxystrobin applied to vegetables according to the recommended procedures were studied. Two applications of azoxystrobin, formulated as a 23% suspension concentrate, were applied to Chinese cabbage（Brassica pekinensis Rupr.）and a leafy vegetable（Chinese kale, B. alboglabra）. Samples were collected at 0, 3, 6, 9, 12, 15, 18, and 21 d after the last application and were extracted into acetonitrile: water（9:1 v/v）. An aliquot of the extract was partitioned with dichloromethane and cleaned-up through a silica column. Residues of azoxystrobin were determined using reversed-phase high performance liquid chromatography with ultraviolet absorption at 255 nm. The limit of detection was 0.02 mg/kg. Recoveries of azoxystrobin from Chinese cabbage and kale were 84.9% and 86.1%, respectively. Results showed that residues of azoxystrobin on Chinese cabbage declined from 4.10 to 0.63 mg/kg within 18 d, and from 13.21 to 0.10 mg/kg within 9 d on Chinese kale. The residue limit of azoxystrobin was respectively established as 2 and 1 mg/kg for Chinese cabbage and kale（as a proxy for leafy vegetables）in Taiwan. The safe harvest intervals were suggested to be 15 and 10 d after the last application for Chinese cabbage and leafy vegetables, respectively."