An Electrochemical Sensor for Simultaneous Determination of Ponceau 4R and Tartrazine Based on an Ionic Liquid Modified Expanded Graphite Paste Electrode

Abstract

A novel electrochemical sensing platform was designed for simultaneous determination of Ponceau 4R and Tartrazine using an ionic liquid modified expanded graphite paste electrode (IL-EGPE). The IL-EGPE was prepared by mixing ionic liquid-expanded graphite composite (IL-EG) with solid paraffin. Based on the advantageous functions of IL and EG, IL-EGPE showed excellent electrocatalytic activity toward the simultaneous oxidation of Ponceau-4R and Tartrazine. Due to the electrocatalytic activity to Ponceau-4R and Tartrazine, a sensor for Ponceau-4R and Tartrazine was constructed based on IL-EGPE. Under optimal experimental conditions, the designed sensor exhibited wide linear responses to Ponceau 4R and Tartrazine ranging from 1.0 × 10−8 to 5.0 × 10−6 mol/L and 1.0 × 10−8 to 2.0 × 10−6 mol/L, respectively. The detection limits for Ponceau 4R and Tartrazine were 1.4 × 10−9 mol/L (0.85 ng/mL) and 3.0 × 10−9 mol/L (1.6 ng/mL) at a signal-to-noise ratio of 3, respectively. This sensor showed good reproducibility, stability and reusability. The proposed sensor was successfully applied in the simultaneous determination of Ponceau-4R and Tartrazine in soft drink with satisfactory results.