Magnetic multi-walled carbon nanotubes assisted solid phase extraction and detection of neonicotinoid pesticides in honey and tea samples

Abstract

In this study, magnetic multi-walled carbon nanotubes (MMWCNTs) were prepared by a one-pot solvothermal method. And they were used as the adsorbent of magnetic solid-phase extraction (MSPE) to extract NEOs. MMWCNTs exhibit good adsorption performance toward NEOs. The adsorption capacities for imidacloprid, thiacloprid, and acetamiprid are 18.4, 25.9, and 18.4 mg g−1, respectively. Also, the adsorption process takes 20 min. The adsorption isotherm fitted to the Langmuir model and the adsorption kinetics was well described by the pseudo-second-order kinetic model. Moreover, the adsorption mechanism was discussed. The MMWCNTs-based MSPE method was combined with field-enhanced sample stacking-capillary electrophoresis (FESS-CE) to realize the sensitive detection of NEOs. The detection limits of NEOs in honey and bottled green tea beverage samples ranged from 7.63 to 16.7 ng g−1. The recoveries were in the range of 84.5 ± 3.2 % to 99.2 ± 1.6 %, with relative standard deviations less than 5.5 %, suggesting the feasibility of the method in actual samples.