SOFT 2004 Meeting Abstracts - Society of Forensic Toxicologists

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P14
TWO FATAL INTOXICATION CASES WITH IMIDACLOPRID: LC~MS ANALYSIS
P.Proen~a*, H.M. Teixeira, F. Castanheira, P. Monsanto, J.Pinheiro, S. Santos, E.P. Marques, D.N. Vieira
National Institute of Legal Medicine, Coimbra, PORTUGAL .
Aim: Imidacloprid [1~(6-chloro-3pyridylmethyl)-N-nitroimidazolidin~2-ylideneamine] is a new and potent
nitro methylene insecticide with high insecticidal activity at very low application rates. It is the first highly
effective insecticide for which the mode of action has been found to deviate from the almost complete and
irreversible blocking of the postsynaptic nicotinergic acetylcholine receptors. The authors present two fatal
cases due to this pesticide, in two males, 33 and 66 years old.
Methods: An LC~MS with electrospray method is described for measuring imidacloprid and its metabolite
in postmortem samples. In the chromatographic separation, a reverse-phase column CIS (2.1xI50mm,
3.5Jlm) was used and the mobile phase composed with acetonitrile and 0.1 % formic acid (15:85), at a 0.25
mllmin flow rate. The samples were prepared by a liquid-liquid extraction procedure with dichloromethane.
Results: Calibration curves for imidacloprid were performed in acetonitrile in blood and urine, achieving
linearity between 0.2Jlg/ml and 15Jlg/ml. The mean recovery was 86%, coefficient of variation was ±5.9%
and the detection limit 2.0ng/ml. Quantitative results were obtained for all postmortem matrices available
of the two fatal cases: blood, urine, stomach contents, liver and kidney. The concentrations found ranged
between 0.29Jlglml (urine) and 350Jlg/mi (stomach contents). Postmortem blood concentrations found were
12.5Jlglml and 2.05Jlg/mL
Conclusions: The authors developed a sensible and validated method to detect and quantify imidacloprid in
postmortem samples and emphasize the lack or even absence of literature with fatal cases related to this
insecticide.
Keywords: Imidacloprid, fatal intoxication, LC-MS
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