L7110

All adsorption experiments were performed by using not only a flow-injection system outfitted with an HPLC pump (model L7110, Hitachi, flow rate 0.1 mL/min), but also a home-built flow cell, a sample injection valve (model 1106, OMNIFIT), a home-built oscillation circuit (including an oscillator and a frequency counter), and a personal computer. The polymer-coated QCM chip was placed into the flow cell. PBS and 0.5% acetic acid were respectively used and injected it into the flow system to equilibrate the newly imprinted chips quickly.

In order to determine the EE and LC, a certain number of microspheres were weighed. Then, they were ground into powder with a mortar and dissolved in methanol. The concentration of naringin was measured by an HPLC (L-7110, Hitachi Instruments Co., Ltd., Tokyo, Japan) at 282 nm. The mobile phase was methanol–water–acetic acid (42:54:4, v/v/v) at a flow rate of 1.0 mL/min. The method was performed on the C₁₈ column (Diamonsil 250 × 4.6 mm) with an injection volume of 20 μL. The concentration of naringin was calculated according to the standard curve. The equations to calculate EE% and LC% were as follows: $$\mathrm{EE}\%=\frac{\mathrm{Total} \mathrm{amount} \mathrm{of} \mathrm{loaded} \mathrm{naringin}}{\mathrm{Initial} \mathrm{amount} \mathrm{of} \mathrm{naringin}}$$
$$\mathrm{LC}\%=\frac{\mathrm{Total} \mathrm{amount} \mathrm{of} \mathrm{loaded} \mathrm{naringin}}{\mathrm{Microspheres} \mathrm{amount}}$$
The particle size of naringin-loaded microspheres was measured by Nano Measurer 1.2 software. Three batches of microspheres were prepared, each with more than 100 microspheres, and they were photographed separately. The scale was determined in the software. Then, each microsphere was labeled and the diameter was determined.

For IR spectra, a Nicolet iS5 FT-IR spectrophotometer (Thermo Fisher Scientific, Waltham, MA, USA) was used. Optical rotation values were measured using a Jasco P-1010 digital polarimeter (Jasco, Tokyo, Japan). NMR spectra were measured with a Jeol ECZ 400 MHz spectrometer (Jeol, Tokyo, Japan). ESIMS and HRESIMS analyses were conducted using the Bruker 7 Tesla solariX FTMS system (Bruker, Bremen, Germany). Column chromatography was carried out with silica gel (230–400 mesh, Merck, Darmstadt, Germany). Thin layer chromatography (TLC) was performed on plates precoated with Kieselgel 60 F₂₅₄ (0.25 mm, Merck), then sprayed with 10% H₂SO₄ solution followed by heating to visualize the spots. Normal-phase high performance liquid chromatography (NP-HPLC) was performed using a system comprising a pump (L-7110, Hitachi, Tokyo, Japan), an injection port (Rheodyne 7725i; Rohnert Park, CA, USA) and a semi-preparative normal-phase column (YMC-Pack SIL, 250 × 20 mm, 5 μm; Sigma-Aldrich, St. Louis, MO, USA). Reverse-phase HPLC (RP-HPLC) was performed using a system comprising a Hitachi L-2130 pump, a Hitachi L-2455 photodiode array detector, a Rheodyne 7725i injection port and a semi-preparative reverse-phase column (Luna, 5 μm, C18(2) 100Å, AXIA, 250 × 21.2 mm; Phenomenex, Torrance, CA, USA).