Development of an on-column enrichment technique based on C18-functionalized magnetic silica nanoparticles for the determination of lidocaine in rat plasma by high performance liquid chromatography

In this study, a novel on-column enrichment technique filled with C18-functionalized magnetic silica nanoparticles was successfully developed for the determination of lidocaine in rat plasma by high performance liquid chromatography (HPLC). The synthesized Fe3O4@SiO2-C18 nanoparticles were locally packed into the capillary by the application of magnets. Lidocaine in the sample solutions pumped into the capillary tube could be easily adsorbed by Fe3O4@SiO2-C18 through hydrophobic interaction by the interior C18 groups, and eluted by acetonitrile solution. Different extraction conditions were investigated. Method validations including linear range, quantification limit, detection limit, precision, accuracy and recovery were also studied. The results showed that the proposed method based on on-column enrichment by Fe3O4@SiO2-C18 was a novel, little solvent and efficient approach for the determination of lidocaine in the complex plasma samples.

► C18-functionalized magnetic silica nanoparticles are packed into the capillary.
► The lidocaine pumped into capillary can be adsorbed by hydrophobic C18 groups.
► The novel on-column extraction method is useful for the determination of lidocaine.