Electrochemical determination of L-methionine using the electropolymerized film of non-peripheral amine substituted Cu(II) phthalocyanine on glassy carbon electrode

This paper reports the stable determination of l-methionine (L-Met) in phosphate buffer solution (pH = 4.0) using the electropolymerized film of 1,8,15,22-tetraaminophthalocyanato-copper(II) (p-4α-CuIITAPc) on glassy carbon electrode (GCE). Bare GCE shows an ill-defined oxidation wave around 1.32 (± 0.02) V for L-Met whereas p-4α-CuIITAPc electrode shows a well-defined oxidation peak at 1.26 (± 0.02) V. The modified electrode does not show any fouling effect towards the oxidation of L-Met. Further, the p-4α-CuIITAPc modified electrode was successfully used for the selective determination of L-Met in the presence of ascorbic acid (AA) and uric acid (UA). Differential pulse voltammetry method was used to determine L-Met in the concentration range of 50–500 μM with a detection limit of 2.7 × 10− 8 M (S/N = 3). The present modified electrode shows good recovery results for spiked L-Met in human blood serum sample.

► Electropolymerized film of non-peripheral amine substituted Cu(II) was fabricated. ► It was used for the stable and selective determination of l-methionine (L-Met). ► A detection limit of 2.7 × 10− 8 M (S/N = 3) was achieved. ► The present method shows good recovery results for spiked L-Met in blood serum samples.