Liquid chromatographic determination of emamectin, milbemectin, ivermectin and abamectin in crops and confirmation by liquid chromatography-mass spectrometry.
Emamectin, milbemectin, ivermectin and abamectin are similar macrocyclic lactone chemicals used as an acaricides or parasiticides. We developed a simultaneous analytical method for determining the residual amounts of these compounds and emamectin metabolites in crops. A sample extracted with acetone was cleaned up with Bond Elut C18 and NH2. The sample was then fluorescence-derivatized with trifluoroacetic anhydride and 1-methylimidazole in acetonitrile. The analyte was measured by HPLC with fluorescence detection using an octadecylsilyl column with 3 microm particle size and gradient elution. In most crops, their recoveries by the developed method were ca. 80-110%. The detection limits of the analytes in vegetables were 0.1-0.3 ppt. Using the developed method, we surveyed the residues of these compounds in 20 commercial crops in Osaka, Japan. The result of the surveillance was that emamectin benzoate of 0.2-6.7 ppb was detected in nine cases and milbemectin of 16.7-279.3 ppb was detected in four cases. The detected samples were confirmed by LC-electrospray ionization (ESI) MS. The limit of detection by LC-ESI-MS was similar to the fluorescence detection level of 0.1-0.3 ppt in vegetables except for milbemectin.
Yoshii
K
K
Ministry of Health and Welfare, National Institute of Health Sciences, Osaka Branch, Japan.
Kaihara
A
A
Tsumura
Y
Y
Ishimitsu
S
S
Tonogai
Y
Y
D000969:Antinematodal Agents / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D018556:Crops, Agricultural / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D021241:Spectrometry, Mass, Electrospray Ionization
D000969:Antinematodal Agents