Liu Hongxia, Song Juanmei, Zhang Shusheng, Qu Lingbo, Zhao Yufen, Wu Yangjie, Liu Huimin
Chemistry Department, Key Laboratory of Chemical Biology and Organic Chemistry of Henan, Zhengzhou University, Zhengzhou 450052, China.
Pest Manag Sci. 2005 May;61(5):511-4. doi: 10.1002/ps.987.
A practical method for analysis of residues of imidacloprid in baked tobacco leaves has been developed using HPLC with liquid-liquid partition clean-up. Imidacloprid was extracted with ethyl acetate under ultrasound, and cleaned up by liquid-liquid partition with 50 g litre(-1) aqueous sodium chloride followed by dichloromethane. The water-soluble and fat-soluble components in tobacco, which interfere with imidacloprid in HPLC, were removed. The separation was performed on a Supelco LC-18 column (250 mm x 4.6 mm ID) with a mobile phase of acetonitrile + 5 mM ammonium acetate (20 + 80 by volume) at a flow-rate of 1 ml min(-1). The baseline separation between imidacloprid and the tobacco blank was achieved within 10 min. With a detection wavelength at 270 nm, the limit of quantitation was 0.04 mg kg(-1). The recovery ranged from 89.8 to 95.4% and the RSDs were less than 2.3%. The proposed method was successfully employed for the determination of imidacloprid residues in 300 samples of flue-cured tobacco leaves.
建立了一种采用高效液相色谱法（HPLC）结合液-液分配净化来分析烤烟叶中吡虫啉残留量的实用方法。吡虫啉在超声条件下用乙酸乙酯萃取，然后用50 g/L的氯化钠水溶液进行液-液分配，再用二氯甲烷净化。去除了烟草中在HPLC分析时干扰吡虫啉的水溶性和脂溶性成分。分离在Supelco LC-18柱（250 mm×4.6 mm内径）上进行，流动相为乙腈+5 mM乙酸铵（体积比20 + 80），流速为1 ml/min。10分钟内实现了吡虫啉与烟草空白的基线分离。检测波长为270 nm时，定量限为0.04 mg/kg。回收率在89.8%至95.4%之间，相对标准偏差小于2.3%。该方法成功用于300个烤烟叶片样品中吡虫啉残留量的测定。
