Simultaneous determination of neonicotinoid insecticides in sunflower-treated seeds (hull and kernel) by LC-MS/MS

ABSTRACT

A validated analytical method to determine seven neonicotinoids (dinotefuran, nitenpyram, thiamethoxam, clothianidin, imidacloprid, acetamiprid and thiacloprid) in sunflower seeds (hull and kernel) using HPLC coupled to electrospray ionisation mass spectrometry (ESI-MS) is presented. Sample clean-up based on a solid–liquid extraction, and the removal of lipid fraction, in the case of kernels, is proposed and optimised. Low limits of detection and quantification were obtained, ranging from 0.3 × 10^–3 to 1.2 × 10^–3 µg g^–1 and from 1.0 × 10^–3 to 4.0 × 10^–3 µg g^–1, with good precision, and recovery values ranged from 90% to 104% for hulls and kernels. The method was applied for the analysis of five thiamethoxam-dressed sunflower seeds and four non-treated seeds, where, besides thiamethoxam, residues of the other neonicotinoid, clothianidin, were also detected and confirmed via tandem mass spectrometry (LC-ESI-MS/MS). Finally, the presence of residues of thiamethoxam and clothianidin in collected sunflower seeds (hulls) coming from coated seeds confirmed the translocation of these neonicotinoids through the plant up to these seeds.

KEYWORDS:

• HPLC-MS/MS
• hull
• kernel
• neonicotinoid
• sunflower seed
• thiamethoxam
• translocation

Acknowledgements

The authors thank the CAR of Marchamalo (Guadalajara, Spain) for supplying the sunflower seed samples.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors gratefully acknowledge funding from the Spanish Ministry Economía y Competitividad and the INIA [grant numbers RTA2013-00042-C10-03 and 06]. L. Sánchez-Hernández thanks the University of Valladolid for her research contract (ref. CIP13/04).