Qualitative identification of imidacloprid in postmortem animal tissue by gas chromatography-tandem mass spectrometry

Abstract

During an avian mass mortality event investigation at the National Fish and Wildlife Forensic Laboratory in Ashland, OR, imidacloprid became an insecticide of concern. A qualitative analytical toxicology screen of seeds, plucks (tongue, esophagus, and trachea), and ventricular contents was requested. A method for the extraction and qualitative analysis of the insecticide in animal tissues was therefore developed. The procedure relies on a combined Food Emergency Response Network (FERN) and QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) approach to sample extraction followed by qualitative analysis by gas chromatography-tandem mass spectrometry. Since imidacloprid is not amenable to the conditions of gas chromatography, a trimethylsilyl derivative was created and characterized. Proposed mechanisms for the creation of this derivative and its mass spectrum are described. The imidacloprid-trimethylsilyl (TMS) derivative was detected in all samples submitted.

Keywords:

• Imidacloprid
• mortality
• avian
• gas chromatography
• tandem mass spectrometry

Acknowledgements

We would like to acknowledge the Southeastern Cooperative Wildlife Disease Study for their initial toxicology work on additional birds from this mortality event.

Disclosure statement

The findings and conclusions in this article are those of the authors and do not necessarily represent the views of the U.S. Fish and Wildlife Service.