Molecularly imprinted polymer functionalized silica nanoparticles for enantioseparation of racemic tryptophan in aqueous solution

A method has been developed for preparation of surface molecularly imprinted polymer functionalized silica nanoparticles (SiO 2 @MPS@MIP). Firstly, the silica nanoparticles are prepared by a one-pot sol-gel method using tetraethylorthosilicate and 3-methacryloxypropyltrimethoxysilane as functional monomers. Next, the template molecule (L-Trp) is self-assembled with the functional monomer (acrylamide). Finally, SiO 2 @MPS@MIP are prepared using N,N′ -methylenebisacrylamide as the cross-linker. The prepared SiO 2 @MPS@MIP have an average diameter of about 6.3 ± 1.2 nm. They exhibit good selectivity toward L-Trp with an imprinting factor of 6.3. The adsorption isotherm data was well described by the Langmuir model. The maximum adsorption capacities of SiO 2 @MPS@MIP for L-Trp and D-Trp were calculated to be 11.1 ± 0.9 and 2.66 ± 0.16 mg g −1 , respectively. An enantiomer excess value of 100% was achieved after adsorption of racemic Trp by the material. The work suggests that SiO 2 @MPS@MIP are a promising material for enantioseparation of Trp racemate in aqueous media. Graphical abstract