Selective and Sensitive Electrochemical Sensor for L ‐Methionine at Physiological pH Using Functionalized Triazole Polymer Film Modified Electrode

This communication describes the determination of an essential amino acid, L ‐methionine ( L ‐Met) in the presence of important interferents, ascorbic acid (AA) and uric acid (UA) at physiological pH using a glassy carbon electrode modified with an electropolymerized film of 3‐amino‐5‐mercapto‐1,2,4‐triazole (p‐AMTa). The bare glassy carbon electrode fails to show a voltammetric signal for L ‐Met in the presence of AA and UA at pH 7.2. However, the p‐AMTa electrode separates the voltammetric signals of AA, UA and L ‐Met with pronounced oxidation currents. The amperometric current of L ‐Met was increased linearly from 1.0×10 −7 to 1×10 −4  M and the detection limit was found to be 4.12×10 −10  M ( S / N =3).