A method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for neonicotinoid pesticide analysis in agricultural products. Four compounds (imidacloprid, clothianidin, acetamiprid, thiacloprid) were extracted with acetonitrile from agricultural products and cleaned up by NH2 solid-phase extraction procedure, and eluted with 0.1% formic acid in methanol/dichloromethane (5/95, v/v). The limit of detection and quantification were 0.0001-0.0005 mg/kg and 0.001 mg/kg, respectively. The mean recoveries of neonicotinoid pesticide from agricultural products were in the range of 90.7-100.9% and 94.4-99.8%, as spiked at 0.2 mg/kg and 0.02 mg/kg, respectively. This validation satisfied the national criteria for pesticide analytical methods. In summary, The present method is fast, precise and sensitive enough for the Positive List System (PLS), and we conclude that the method is also suitable for neonicotinoid pesticide determination in a wide range of agricultural products.

솔수염하늘소는 소나무재선충병을 매개하는 중요한 해충으로 성충의 방제를 위하여 주로 항공살포나 지상살포에 의한 살충제의 접촉독에 의한 방제가 시행되어 왔다. 본 연구는 살충제를 나무주사하여 소나무재선충병의 매개충인 솔수염하늘소를 방제하기 위한 살충제 선발을 위해 Neonicotinoid계 살충제 7종을 각 2,000배로 희석한 후 솔수염하늘소 에 2㎕를 경구투여하여 소화중독에 의한 살충효과를 평가하였다. 살충제 경구 투여 후 신경흥분에 의한 경련반응을 조사한 결과 30분 경과에서는 Clotianidin SL(100%), Thiamethoxam DC(73.3%)이 경련 비율이 높았으며 상대적으로 Dinotefuran SL(46.7%), Imidacloprid DC(0.0%)가 약제에 대한 경련반응이 낮게 나타났다. 반수치사시간(LT50)을 조사한 결과 Clotianidin SL은 수컷에서 54.7시간, 암컷에서는 85.6시간으로 나타났으며, Thiamethoxam DC은 암컷에서 70.1시 간, 수컷에서는 88.7시간으로 나타나 소화중독 효과가 가장 우수한 것으로 나타났다. 따라서 살충제 나무주사를 이용하여 솔수염하늘소의 방제에서는 Clotianidin SL, Thiamethoxam DC가 가장 적합한 약종이라고 판단되었다.

In this study, we confirmed that the pesticides flow out into streams during rainfall by the way of helicopter spraying. The maximum concentration was 23 pg·mL-1 and the distribution of concentrations showed similar to the normal distribution. The runoff characteristics of insecticides using helicopter spraying was affected by the elapsed time of the start from spraying until rainy days and rainfall intensity. The pesticide concentrations of sample ranged from 0.65 to 3.04 pg·mL-1. Fish kill did not occurred in the stream and the lake cause of the pesticides runoff. Aquatic animals, such as Orthrias toni, Rhinogobius brunneus, tadpole etc. were still alive in the stream. It indicates that this class of pesticide does not cause toxic to fish by runoff event. However, the honey bee kill event was reported in the spray region during the helicopter spraying period. The further study such as ecotoxicity test is needed to reveal the pesticides effect reach to the ecosystem.