Non-target evaluation of contaminants in honey bees and pollen samples by gas chromatography time-of-flight mass spectrometry

This work presents a non-targeted screening approach for the detection and quantitation of contaminants in bees and pollen, collected from the same hive, by GC-EI-ToF-MS. It consists of a spectral library datasets search using a compound database followed by a manual investigation and analytical standard confirmation together with semi-quantitation purposes. Over 20% of the compounds found automatically by the library search could not be confirmed manually. This number of false positive detections was mainly a consequence of an inadequate ion ratio criterion (30%), not considered in the automatic searching procedure. Eight compounds were detected in bees and pollen. They include insecticides/acaricides (chlorpyrifos, coumaphos, fluvalinate-tau, chlorfenvinphos, pyridaben, and propyl cresol) at a concentration range of 1-1207 mu g kg(-1), herbicides (oxyfluorfen) at a concentration range of 212 -1773 mu g kg(-1) and a growth regulator hormone (methoprene). Some compounds were detected only in pollen; such as herbicides (clomazone), insecticides/acaricides and fungicides used to control Varroa mites as benzylbenzoate, bufencarb, allethrin, permethrin, eugenol and cyprodinil. Additional compounds were detected only in bees: flamprop-methyl, 2-methylphenol (2-49 mu g kg(-1)) and naphthalene (1-23 mu g kg(-1)). The proposed method presents important advantages as it can avoid the use of an unachievable number of analytical standards considered target compounds a priori but not present in the analyzed samples. (C) 2017 Elsevier Ltd. All rights reserved.