Fe3O4@PDA@PANI core–shell nanocomposites as a new adsorbent for simultaneous preconcentration of Tartrazine and Sunset Yellow by ultrasonic-assisted dispersive micro solid-phase extraction

[Display omitted] •SY and Tar were preconcentrated by ultrasonic-assisted D-μ-SPE method.•Fe3O4@PDA@PAN core–shell nanocomposites were synthesized, characterized.•The derivative spectrophotometric method was successfully applied.•The method was sensitive, economic, and easily applicable to various food samples.•The adsorption capacity and reusability of Core-shell nanoparticles were significant. In this research, novel magnetic Fe3O4@PDA@PANI core–shell nanoparticles were designed and fabricated as an efficient adsorbent in the service of ultrasound-assisted dispersive micro-solid phase extraction for simultaneous preconcentration of Sunset Yellow (SY) and Tartrazine (Tar) before UV–Vis spectrophotometric detection. This adsorbent was fully characterized by Fourier Transform Infrared (FT-IR) spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Energy Dispersive X-ray (EDX) analysis. To overcome the spectral overlapping of SY and Tar dyes, the derivative spectrophotometric method was successfully used for the simultaneous detection of dyes in their binary solutions. The operating parameters affecting preconcentration efficiency and spectrophotometric determination were optimized. Under optimal conditions, the limit of detections (LOD) was obtained 0.2 and 0.5 ng mL−1 for SY and Tar, respectively. The adsorption capacity and reusability of core–shell nanoparticles were significant. The satisfactory results of analysis of a few real samples indicate that the method is very favored in the analysis of various complex matrices.