Trace analysis of ponceau 4R based on the signal amplification of copper-based metal-organic framework modified electrode

It is quite important to research rapid and sensitive analytical method for ponceau 4R due to its adverse health effects. In this work, a kind of copper-based metal-organic frameworks were prepared using 1,3,5-Benzenetricarboxylic acid (H3BTC) as the ligand, and then used to construct a novel electrochemical sensing platform for ponceau 4R. The prepared Cu-BTC frameworks exhibit strong surface accumulation ability toward ponceau 4R, and then enhance the oxidation activity of ponceau 4R effectively. On the surface of Cu-BTC modified electrode, the oxidation signals of ponceau 4R are enhanced significantly, and consequently the detection sensitivity is obviously improved. The influences of pH value, modification amount of Cu-BTC and accumulation time were studied. As a result, a sensitive, rapid and convenient electrochemical method was developed for the determination of ponceau 4R. The linear range is from 1.25 to 500ngmL−1, and the detection limit is 0.65ngmL−1 (1.08nM). It was used in different drink samples, and the detected results consisted with the values of that obtained by high performance liquid chromatography.