MnCoFe-LDH/Ni-MOF nanocomposite-coated hollow fiber membrane for solid phase extraction of amaranth dye from water and food samples followed by spectrophotometric analysis

Abstract

In the present study, the new composite based on MnCoFe-LDH nanoflower/Ni-MOF/ hollow fiber membrane (HFM) was synthesized in such a way that first MnCoFe-LDH and Ni-MOF nanoparticles were synthesized separately, then converted into a composite and finally coated on the surface of the HFM. The final composite was characterized using FT-IR, XRD, SEM, and EDX analysis and applied as a promising and effective sorbent for the solid-phase microextraction of amaranth dye (as a model analyte) in various water and food samples, followed by spectrophotometric analysis. It should be noted that two main driving forces for conducting the extraction process are the electrostatic and π-π interactions between the surface of the adsorbent and the analyte molecule. By using this proposed adsorbent, the requirement for using a centrifuge for phase separation was eliminated. Furthermore, there was no necessity to use the vortex or the stirrer to carry out the adsorption and desorption steps, and only by hand-shaking of the sample solution, high extraction recovery was achieved. These advantages made the extraction process greener, quicker, and easier. Optimizations of all parameters affecting the proposed method (such as pH, sample solution, HFM size, adsorption time, and desorption time) were done using the central composite design methodology. The findings indicate that the calibration graphs exhibited linearity in the range of 20.0–1000 µg/L, with the limit of detection of 5.6 µg/L, the limit of quantification of 17.2 µg/L, and the correlation coefficient of 0.9981 for the model analyte. Furthermore, the relative recovery was obtained in the range of 93.6–101 %. In addition, intra-day RSD, inter-day RSD, and preconcentration factor (PF) were achieved at 3.8, 6.9, and 30, respectively. The suggested sorbent was successfully synthesized and applied for effective solid-phase microextraction of amaranth dye in different real samples.