Superhydrophobic Fe3O4 nanoparticles for selective magnetic solid phase extraction of Rhodamine B in cosmetic and food samples

Abstract

The detection of potentially harmful chemicals such as Rhodamine B (RhB) in consumer products is key for the public health. Although the use of RhB is prohibited due to its highly toxic properties, it is used in different cosmetics and foods because of its low cost and broad availability. Therefore, appropriate analytical techniques are required to monitor such compounds. Since RhB is a predominantly apolar molecule, it can be extracted selectively and effectively by using materials with a dominant hydrophobic character in its isolation from the matrix environment. In this study, methyl-terminated polydimethylsiloxane (PDMS) grafted Fe₃O₄ nanoparticles (PDMS-Fe₃O₄ NPs) were synthesized as a superhydrophobic medium and used for magnetic solid phase extraction of RhB at trace level prior to it’s UV-Vis spectrophotometric analysis. The superhydrophobic PDMS- Fe₃O₄ NPs exhibit selective attraction to RhB and repulsion from other compounds, thereby enhancing the accuracy of the analysis. Along with magnetic solid phase extraction, effects of pH, the quantity of adsorbent, the type and volume of eluent, the volume of the sample, and the optimization of the real sample were investigated. The limit of detection (LOD), limit of quantification (LOQ) and preconcentration factor (PF) values of the proposed magnetic solid-phase extraction MSPE method were calculated as 0.5 µg·L⁻¹, 1.7 µg·L⁻¹ and 267, respectively. The MSPE method can be applied for various cosmetic and food samples for the sensitive and accurate determination of trace RhB with high recoveries that range from 86.4 % to 103.7 %.