Hao, ChunyanEng, MargaretMorrissey, ChristySun, Fengrong2020-05-072020-05-0712/10/2018Hao, C., Eng, M.L., Sun, F., Morrissey, C.A. (2018). Part-per-trillion LC-MS/MS determination of neonicotinoids in small volumes of songbird plasma. Science of the Total Environment, 644:1080-1087. https://doi.org/10.1016/j.scitotenv.2018.06.317http://hdl.handle.net/10388/12824Neonicotinoids are the most widely used class of insecticides in the world, and there are increasing concerns about their effects on non-target organisms. Analytical methods to diagnose exposure to neonicotinoids in wildlife are still very limited, particularly for small animals such as songbirds. Blood can be used as a non-lethal sampling matrix, but the sample volume is limited by body size. Neonicotinoids have a low bioaccumulation potential and are rapidly metabolized, therefore, sensitive assays are critically needed to reliably detect their residues in blood samples. We developed an efficient LC-MS/MS method at a part-per-trillion (pg/ml) level to measure eight neonicotinoid related insecticides (acetamiprid, clothianidin, dinotefuran, flonicamid, imidacloprid, nitenpyram, thiacloprid and thiamethoxam) plus one metabolite (6-chloronicotinic acid) in small volumes (50 μL) of avian plasma. The average recovery of target compounds ranged from 95.7 to 101.3%, and relative standard deviations were between 0.82 and 2.13%. We applied the method to screen blood samples from 36 seed-eating songbirds (white-crowned sparrows; Zonotrichia leucophrys) at capture, and detected imidacloprid in 78% (28 of 36), thiamethoxam in 22% (8 of 36), thiacloprid in 11% (4 of 36), and acetamiprid in 11% (4 of 36) of wild-caught sparrows. 6 h after capture, birds were orally dosed with 0 (control), 1.2 or 3.9 mg of imidacloprid/kg bw, test results using this method indicated that plasma imidacloprid was significantly elevated (low 26-times, high 316-times) in exposed groups. This is the first study to confirm neonicotinoid exposure in small free-living songbirds through non-lethal blood sampling, and to demonstrate that environmentally realistic doses significantly elevate circulating imidacloprid concentrations. This sensitive method could be applied to characterize exposure to neonicotinoids in free-living wildlife and in toxicological studies.enAttribution-NonCommercial-NoDerivs 2.5 CanadaNeonicotinoids6-Chloronicotinic acid (6-CNA)Liquid chromatography-tandem mass spectrometry (LC-MS/MS)Multiple reaction monitoring (MRM)Blood plasmaPreprinthttps://doi.org/10.1016/j.scitotenv.2018.06.317