CoFe2O4 decorated graphene/C18-functionalized mesoporous silica nanocomposites prepared for magnetic enrichment and electrochemical detection of promethazine in beef

Abstract

Promethazine (PHZ) is used as a sedative in veterinary medicine, and its residue can threaten the health of human. The electrochemical detection of PHZ is suitable method for application in the field. However, the traditional electroanalysis is difficult to perform directly in meat samples due to matrix interference. This work integrates magnetic solid-phase extraction and differential pulse voltammetry for highly sensitive and selective determination of PHZ in beef and beef liver for the first time. CoFe2O4/graphene coated with C18-functionalized mesoporous silica (MG@mSiO2-C18) is synthesized as dispersed magnetic adsorbent to extract PHZ. Magnetic glassy carbon electrode modified with nitrogen-doped hollow carbon microspheres (HCM) attracts the MG@mSiO2-C18 with PHZ, and directly detects the PHZ without elution procedure. MG@mSiO2-C18 can separate PHZ to avoid the interference of impurities on following detection, and also concentrate PHZ on magnetic electrode. Additionally, the electrode modification with HCM can amplify the electrochemical signal of PHZ. Finally, the integrated PHZ determination method exhibits a wide linear range from 0.08 µmol/L to 300 µmol/L with a low limit of detection of 9.8 nmol/L. The beef sample analysis presents excellent recovery, demonstrating that this protocol is promising for the rapid and onsite detection of PHZ in real meat samples