Voltammetric determination of amoxicillin using gold nanoparticles modifiedglassy carbon electrode

Amoxicillin (AMX) is one of the most frequently used β-lactam antibiotics in the world. Becauseof therapeutic importance, development of rapid and sensitive methods for clinical monitoring ofAMX are important [1]. Different analytical techniques have been applied for determination ofAMX such as HPLC [2] and voltametric methods [3-5]. The HPLC method have been often timeconsuming processes and are usually expensive. In this study, a novel modified electrode isprepared by electrochemical deposition of nano‐Au on the surface of a poly(L‐methionine)(PMT)‐modified glassy carbon electrode (GCE). The nano‐Au/PMT/GCE was used as a novelsensor for determination of AMX in biological sample.MethodPolymerization of L‐methionine on the GCE was performed using cyclic voltammetry in anaqueous solution of L‐methionine (2.5 mM) and phosphate buffer solution (0.1 M). Nano‐Au waselectrochemically deposited on the PMT/GCE surface by applying a cathodic potential of –0.23V for 300 s in HAuCl4 solution (0.5 mM). The obtained nano‐Au modified PMT film electrodewas washed with deionized water and is namely nano‐Au/PMT/GCE.Result and discussionThe parameters of the L‐methionine concentration and pH of the supporting electrolyte solutionwere optimized by CV methods. Optimum conditions were 2.5 mM of L‐methionine and pH of 9.Fig. 1 shows CVs of nano‐Au/PMT/GCE in phosphate buffer solution (PBS, pH = 9.00) in theabsence an presence of 0.1 mM AMX. No anodic current was observed in the surface of bare GCE. The anodic current for electrooxidation of AMX at the surface of nano‐Au/PMT/GCE wassignificant. As a result, this improvement in the oxidation current demonstrates that incorporationof nano‐Au and PMT onto a GCE enhances the electrochemical signal of AMX electrooxidation.ConclusionIn this study, a novel AMX sensor was fabricated by modification of GCE using nano‐Au andpoly (L‐methionine). The modified electrode showed excellent sensitivity, selectivity, and antifoulingproperties for the voltammetric determination of AMX.

Keywords:

Electrochemical determination , Voltammetry , Amoxicillin , Gold nanoparticle