Chemometric-assisted electrochemical sensor for simultaneous determination of neonicotinoids imidacloprid and thiamethoxam in honey samples†

Neonicotinoids are systemic insecticides used in agriculture. In particular, imidacloprid (IM) and thiamethoxam (TM) have selective toxicity to insects, and they have been implicated in the steep decline of the global honeybee population, specifically in colony collapse disorder (CCD). Some scientific reports have shown that a significant amount of honey worldwide contains traces of neonicotinoids, at levels strong enough to cause damage to bees. Therefore, the development of portable and low-cost sensor devices to permit rapid detection of these neonicotinoids in the field (in situ) is of great importance. The main goal of this work was the development of an electrochemical method, for the first time, to simultaneously determine IM and TM, which can occur in honey samples from Argentina. The electrochemical sensor was based on a pretreated glassy carbon electrode (GCE) using square wave voltammetry (SWV) as the analytical technique. All parameters involved in the response were optimized using a central composite design. The SWV response was modeled using the artificial neural network (ANN) algorithm. Recovery experiments were performed with spiked honey samples, yielding recovery values from 90% to 107% without pretreatment of the samples. The proposed method is presented as a very good and simple alternative for determining IM and TM in Argentina honeys samples.