Detection of Ponceau 4R in foods based on an expanded graphite paste electrode

In this work, a sensitive and simple method was first developed for electrochemical determination of Ponceau 4R (E 124) based on an expanded graphite paste electrode (EGPE) by the square-wave stripping voltammetry (SWSV) method. The EGPE displayed good analytical performance for the measurement of Ponceau 4R. Under the optimum experimental conditions, Ponceau 4R could be linearly detected in the wide concentration range of 1.0 × 10−8 to 3.0 × 10−6 M, with a detection limit down to around 6.3 × 10−9 M at signal to noise ratio of 3:1. The developed method was successfully applied to the determination of Ponceau 4R in food samples with satisfying results and the results agreed with those from the high performance liquid chromatography (HPLC).