Uptake and translocation monitoring of imidacloprid to chili and tomato plants by molecularly imprinting extraction - ion mobility spectrometry

The degradation of imidacloprid in soil and its uptake and translocation to chili and tomato plants was evaluated, as a proof of concept, of the possibilities of the combination of molecularly imprinted polymers (MIPs) and ion mobility spectrometry (IMS) for a fast and sensitive bioprocesses monitoring tool. To do it, a method based on the selective extraction of imidacloprid from soil and plant materials was developed. In the selected conditions, the MIP-IMS procedure provided a recovery of imidacloprid in soil and plant samples from 102 to 114%, for spiked concentration levels from 0.2 to 2.0 μg g−1. Precision of the methodology, expressed as the relative standard deviation (RSD) of a 100 and 1000 μg L−1 imidacloprid standard solution was 11 and 6%, respectively, being the RSD for the analysis of a soil sample spiked at a concentration level of 1 μg g−1 of 11% (n = 4). Limits of detection and quantification of 0.03 and 0.10 μg g−1 in the solid sample were also obtained, respectively. Regarding imidacloprid degradation, this study evidenced that the process follows a first order kinetics with a half-life between 39 and 45 days in soil, being necessary a growing period of 33 days before pesticide detection in stems and leaves.