A sustainable magnetic γ-Fe2O3@Escherichia coli (E. coli) bio-sorbent for determination trace amounts of thymol in pharmaceutical, food and cosmetic samples

Abstract

Due to the need for environmentally friendly technologies, using microorganisms such as bacteria as a biosorbent for the solid phase extraction (SPE) technique has paid attention. These biosorbents have advantages, such as good performance, abundance and accessibility, operation over a wide range of environmental conditions, regeneration, and not producing secondary contaminations. This study examines a biotechnological application using Escherichia coli (E. coli), as a highly efficient adsorbent for separation, preconcentration, and determination of thymol. The E. coli was immobilized to γ-Fe2O3 magnetic nanoparticles, as a solid-phase biosorbent, for magnetic dispersive micro-solid phase extraction (MDμ-SPE) to provide an efficient and rapid recovery after the sorption process. Characterization of the prepared biosorbent was carried out using the Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscope (FE-SEM), and vibrating sample magnetometer (VSM). The MDμ-SPE as a green and sensitive method proposed for the separation and determination of trace quantities of thymol. Some experimental factors, such as sample pH, amount of sorbent, adsorption time, and temperature affecting the MDμ-SPE efficiency, were tested by the experimental design method. Under optimal conditions, linear range, detection limit, and the relative standard deviation for extraction and preconcentration of thymol were obtained; 30–500, 9.1 ng mL−1, and 1.4 %, respectively. Finally, the proposed method was successfully applied to the preconcentration and determination of target analyte in pharmaceutical, food, and cosmetic samples.