Abstract: A hydrophobic ionic liquid modified thermo-responsive molecularly imprinted monolith was synthesized using N-isopropylacrylamide as a thermo-responsive monomer and a long-chain hydrophobic ionic liquid as an auxiliary modification monomer. The ionic-liquid-modified thermo-responsive molecularly imprinted polymer was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. When the column temperature was 50 °C, the synthesized monolithic column was successfully applied to the selective separation of homologue tanshinones within 7 min and eluted only by water (mobile phase) (theoretical plates more than 1.00 x 105 per m). The negative Gibbs free energy (£ -2.37) values showed that the transfer of the tanshinones from the mobile phase to the stationary phase on this monolithic column was a thermodynamically spontaneous process. Good linearity of the five tanshinones by thermo-responsive monolith was obtained in the range 0.100-25.0 μg mL-1. The limit of detection (S/N = 3) and limit of quantitation (S/N = 10) were less than 0.0390 and 0.0630 μg mL-1, respectively, with a relative standard deviation of less than 4.8%. In this proposed thermo-responsive chromatography method, the separation of homologue analytes can be achieved by changing the column temperature and the use of water as the mobile phase would decrease the economic cost and organic pollution. This article is protected by copyright. All rights reserved
Author keywords: Ionic liquids, Molecularly imprinted polymers, tanshinones, Thermo-Responsive Polymers