In the present research, the surface modification of MnO2 nanoparticles was done through the in-situ polymerization of green tea polyphenols in the presence of lysine and formaldehyde. The new composite (MnO2@tea polyphenols) is used as an efficient sorbent in dispersive solid-phase extraction (DSPE) of methyl, ethyl, propyl, and butyl parabens followed by HPLC-UV. Fourier-transform infrared (FT-IR), field emission scanning electronic microscope (FE-SEM), nitrogen adsorption–desorption analysis, energy-dispersive spectra (EDS), X-ray powder diffraction (XRD), and zeta potential were used to characterize the prepared sorbent. After optimization using response surface methodology, the linearity and limits of detection were in the range of 0.1–500 μg/L and 0.08–0.3 μg/L, respectively. Acceptable relative recoveries of more than 91.6% with RSDs of less than 5.1% were achieved for spiking wastewater and cosmetic samples.
