Electric field-assisted solid phase extraction and cleanup of ionic compounds in complex food matrices:...

The use of electric fields as additional driving forces in sample preparation techniques is an innovative approach that is environmentally friendly, straightforward, and able to overcome several limitations of conventional sample preparation procedures. In this work, the advantages of electric field-assisted solid phase extraction (E-SPE) using syringe-type cartridges were demonstrated for the extraction of four fluoroquinolones (FQs) in their anionic forms. The FQs were extracted from eggs and subsequently determined by UHPLC-MS/MS. The use of electric fields during the washing and final elution steps resulted in a significant improvement of the extraction efficiencies for almost all FQs when compared to conventional SPE. Intra- and inter-day assays showed coefficients of variation below 10%. The better cleanup also resulted in the appearance of less precipitated matter in the final eluate, as well as reduced matrix effects. The results showed that the electrophoretic forces derived from electric fields are a promising way of significantly increasing the extraction efficiency of ionic analytes, while minimizing matrix effects associated with complex samples.