Neonicotinoids: An overview of the newest sample preparation procedures of environmental, biological and food matrices

An overview of the actual state-of-the-art sample treatment procedures for trace and ultra-trace determination of neonicotinoids (NQs) in environmental, food and biological samples is presented. Analytical procedures for NQs, sometimes together with their metabolites/by-products, and NQ-related new generation pesticides have been considered, focusing on sample preparation, which is essential in most cases due to both the complexity of the matrices and low concentrations of residual analytes. Different strategies have been practised for analytes extraction/preconcentration/cleanup, entailing various techniques as solid-liquid extraction (SLE), liquid-liquid extraction (LLE), offline and online solid-phase extraction (SPE), dispersive SPE (d-SPE), magnetic SPE (MSPE), solid-phase microextraction (SPME) and the quick, easy, cheap, effective, rugged and safe (QuEChERS) approach. New solid phases, including inorganic and carbon-based materials, have been prepared, also starting from "green" precursors, and successfully employed in the sample treatment step before hyphenated liquid chromatography or direct electrochemical detection. As well, new environmentally friendly solvents have been evaluated for LLE. The most recent studies (2022-present), around 50 papers, have been reviewed by matrix type, briefly described and commented concerning extraction efficiency, matrix effect, sensitivity, ease of application and sample throughput. Advantages and drawbacks were highlighted, as well as new achievements paving the way for further improvements.