Simultaneous Determination of Carmine and Amaranth Based on a Poly(L-Arginine)–Graphene Modified Electrode

Abstract

The poly(L-arginine)–graphene modified glassy carbon electrode (GCE) was fabricated and the electrochemical behavior of carmine and amaranth on this electrode was studied by cyclic voltammetric method. Compared with poly(L-arginine)/GCE and GCE, the poly(L-arginine)–graphene modified GCE improved the sensitivity for the determination of carmine and amaranth. The experimental results indicated that the oxidation peaks of carmine and amaranth were separated at 121 mV in phosphate buffer solution at pH 2.5. The linear range for the simultaneous determination of carmine and amaranth were 7.5 × 10^–7–7.5 × 10^–5 M. The detection limits were 7 × 10^–8 M for carmine and 2.5 × 10^–7 M for amaranth. The method has been applied to the simultaneous determination of carmine and amaranth in drinks with satisfactory results.