The synthesis, adsorption mechanism and application of polyethyleneimine functionalized magnetic nanoparticles for the analysis of synthetic colorants in candies and beverages

Abstract A green and simple method was designed to synthesize polyethyleneimine (PEI)-modified magnetic nanoparticles (MNPs), which were later used as adsorbents in magnetic solid phase extraction (MSPE) process. A new MSPE-HPLC method was then established for the simultaneous determination of four representative synthetic colorants (Amaranth, Ponceau 4R, Sunset yellow and Allure red) in food samples. Several important factors, such as the pH of the sample solution, the amount of adsorbent, the adsorption time, and the type of the eluent were investigated in detail. Under the optimized experimental conditions, the four colorants were measured with good linearity, detection limit and quantification limit. Adsorption kinetics and isotherms were also investigated to elucidate the adsorption mechanism. The detection of four colorants in candy, jelly and carbonated drink proved that the established MSPE-HPLC method was simple and effective and can be used for the analysis of colorants in real samples.