Magnetic supramolecular solvent based magnetic surfactant: Synthesis, physicochemical properties, and application

Magnetic solvents have been recently introduced to reduce the time required for phase separation. Compared with magnetic materials, magnetic solvents show simpler preparation and better repeatability. These solvents have a strong response to external magnetic fields due to the presence of metal ions in their structure. This feature causes easy magnetic separation in analytical sample preparation steps. However, reported magnetic solvents present drawbacks such as high viscosity and expensive and time-consuming synthesis procedures. In some cases, large amounts of toxic solvents are used in the preparation steps posing potential environmental challenges.

A new category of magnetic solvents, magnetic supramolecular solvent (MSUPRAS), was introduced here. MSUPRAS is an intrinsically magnetic nanoparticle-free solvent like other magnetic liquids, and the magnetic component is part of its structure. MSUPRAS offers advantages like ease of synthesis from a magnetic amphiphilic molecule, cost-effectiveness, and lower toxicity. Amphiphilic molecules are usually inexpensive and readily available from nature or obtained through chemical synthesis. Although MSUPRAS is a type of amphiphilic solvent, it is prepared at room temperature without special synthesis conditions including concentrated acid or a toxic solvent. The physicochemical properties of MSUPRAS can be tailored by choosing suitable ingredients for synthesis. The potential for modeling phase behavior based on the mole fraction of constituents in the mixture suggests a practical approach for predicting and optimizing solvent performance.

Due to its amphiphilic nature, MSUPRAS possesses a hydrophobic and a hydrophilic part, which can provide different interactions with the target analytes. Thus, it has high extraction capabilities for polar and non-polar compounds. Also, magnetic phase separation can accelerate the extraction procedure, and the time-consuming step of centrifugation is eliminated. Therefore, the extraction strategy is simple, rapid, and energy efficient.