title: Column switching liquid chromatography and post-column photochemically fluorescence detection to determine imidacloprid and 6-chloronicotinic acid in honeybees.
abstract: The determination of imidacloprid and its main metabolite (6-chloronicotinic acid) in honeybees was performed by liquid chromatography with post-column photochemical derivatisation in alkaline medium and fluorescence detection. The compounds were extracted from honeybees with acetone under ultrasound conditions prior to liquid-liquid partition with dichloromethane. The separation of extract components was performed using a 50 mm x 4.6 mm i.d. short column packed with 5 microm Aquasil C(18) using an acetonitrile:water gradient program as mobile phase. Injection of samples in 0.1 mol L(-1) H(3)PO(4)/KH(2)PO(4) buffer solution (pH 3) improved the chromatographic separation between the most polar components of matrix and the 6-chloronicotinic acid. Matrix components were removed to waste using an on-line clean-up method previously to post-column reaction. Limits of quantification were 0.3 and 5.0 microg L(-1) (corresponding to 1.2 and 20.0 microg kg(-1) in the honeybee sample) for imidacloprid and 6-chloronicotinic acid, respectively. The recovery was ranged from 80.2 to 91.7% with a relative standard deviation lower than 9.0%.
authors.affiliation: Department of Hydrogeology and Analytical Chemistry, University of Almería, La Cañada de San Urbano, 04120 Almería, Spain. mdgil@ual.es
authors.forename: M D Gil
authors.initials: MD
authors.lastname: García
authors.forename: M Martínez
authors.initials: MM
authors.lastname: Galera
authors.forename: R Santiago
authors.initials: RS
authors.lastname: Valverde
authors.forename: A
authors.initials: A
authors.lastname: Galanti
authors.forename: S
authors.initials: S
authors.lastname: Girotti
mesh_terms: D000818:Animals; D001331:Automation; D001516:Bees / Q000737:chemistry* / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D007093:Imidazoles / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D000073943:Neonicotinoids; D009539:Nicotinic Acids / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D009574:Nitro Compounds / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D010777:Photochemistry / Q000379:methods; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence
chemical_list: D007093:Imidazoles; D000073943:Neonicotinoids; D009539:Nicotinic Acids; D009574:Nitro Compounds; C082359:imidacloprid; C035953:6-chloronicotinic acid