Tailoring monosize molecularly imprinted solid phase extraction polymers for selective stigmasterol isolation from soybean oil

Stigmasterol (Stg) is a member of the phytosterol family, which is found naturally in plants in the form of free alcohol or their sediments, especially vegetable oils, and has positive effects on health such as anti-inflammatory, anti-osteoarthritis, anti-atherogenic, antioxidant, and lowering plasma cholesterol level, and protective effects such as anti-cancer. In this study, we aimed to prepare monosize Stg-imprinted solid phase extraction polymers (Stg-Mip-MSPEs) for direct separation of Stg from soybean oil extract. The synthesized polymers were characterized by scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). Stg-Mip-MSPE has maximum Stg adsorption capacity as 73.2 mg/g while NIP-MSPE has as 8 mg/g. Selectivity studies showed that Stg-Mip-MSPEs can recognize Stg 1.45 and 2.73 times more selective than cholesterol and ergosterol molecules, respectively. The Stg rebinding capacity from soybean oil was calculated as 63.69% and also showed the selective Stg binding ability of Stg-Mip-MSPEs from real samples. The reusability studies showed that the Stg adsorption capacity of Stg-Mip-MSPEs remains 96% at the end of the tenth cycle.