Quantitative determination of pesticide residues in specific parts of bee specimens by nanoflow liquid chromatography high resolution mass spectrometry.

The presence of pesticide residues in bees is of great interest, given the central role of bees as indicators for environmental assessment. The goal of this article is to propose a method to capture enhanced chemical information for these central environmental indicators. Most of the methods rely on the analysis of pooled samples rather than individual specimens due to practical sample preparation method considerations and limitations in sensitivity. This leads to miss information on the mapping of pesticides and actual amount of pesticide per specimen. In this article, a nanoflow liquid chromatography system coupled to high resolution mass spectrometry (using a hybrid quadrupole-Orbitrap instrument) has been applied for the development of a multiresidue pesticide method for the determination of 162 multiclass pesticides in specific part of honeybee samples (ca. abdomen, head or thorax). The reduced flow rate provided an enhancement in sensitivity and a strong reduction of matrix effects, thus only a quick and simple ultrasound assisted extraction using minute amount of sample was required. Satisfactory results were obtained for all tested analytes with concentration levels detected lower than 0.5 ng g in all cases, thus being acceptable for monitoring purposes. Matrix effect was negligible for 94% of compounds. Extraction recoveries ranged from 70% to 105%, being within SANTE guidelines. Finally, the applicability of the method was demonstrated, by successful application to the analysis of contaminated honeybee samples, extracting useful information from specific bee parts of single specimens, thus, enabling pseudo spatially resolved chemical information.