Analysis of residues of imidacloprid in tobacco by high-performance liquid chromatography with liquid-liquid partition cleanup.
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.
Liu
Hongxia
H
Chemistry Department, Key Laboratory of Chemical Biology and Organic Chemistry of Henan, Zhengzhou University, Zhengzhou 450052, China.
Song
Juanmei
J
Zhang
Shusheng
S
Qu
Lingbo
L
Zhao
Yufen
Y
Wu
Yangjie
Y
Liu
Huimin
H
D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D007093:Imidazoles / Q000032:analysis / Q000737:chemistry*; D007306:Insecticides / Q000032:analysis / Q000737:chemistry*; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010573:Pesticide Residues / Q000032:analysis / Q000737:chemistry*; D014026:Nicotiana / Q000737:chemistry*
D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010573:Pesticide Residues; C082359:imidacloprid