Determination of 5 Small Molecular Substances in Intraocular lens by Gas Chromatography-Mass Spectrometry with n-Hexane Extraction

The 5 small molecule substances, including hydroxyethyl methacrylate (HEMA), ethoxyethyl methacrylate (EOEMA), ethylene glycol dimethacrylate (EGDMA), trimethylolpropane trimethacrylate (TMPTMA), and 3-(2H-benzod1,2,3triazol-2-yl)-4-hydroxyphenethyl methacrylate (UVE), in essential commercially available hydrophilic acrylic intraocular lens products were determined by the method mentioned by the title. The intraocular lens sample was dried at (60±2) ℃ to a constant mass, about 0.2 g of which was taken. The 160 mL of extraction solvent (n-hexane) was added,and Celsius Soxhlet extraction was made at 70 ℃, repeatedly extracting 5 times within 1 h for a total of 5 h. All the extraction solution was collected, and evaporated to near dryness,and the resulting solution was made its volume up to 10 mL with n-hexane. The complete extraction solution obtained was analyzed by gas chromatography-mass spectrometry. About 1.1 g of the raw material embryo of the above sample was taken, and 11 mL of n-hexane was added. The mixture was settled at (35±2) ℃ (simulating human eye temperature) for 72 h,and then the raw material embryo was taken. The dissolution extract obtained was analyzed by gas chromatography-mass spectrometry. In chromatographic analysis, a SH-Rxi-5MS column was used as the stationary phase, and high-pressure injection was carried out under the conditions of initial column temperature of 80 ℃, column heating rate of 10 ℃·min⁻¹ and 15 ℃·min⁻¹, injection port temperature of 250 ℃, and injection volume of 1 μL. In mass spectrometry analysis, EI source was used for ionization, selected ion monitoring mode was used for detection, and external standard method was used for quantification. It was shown that linear relationships between values of the mass concentrations and peak areas of the 5 small molecule substances were kept in definite ranges, with detection limits (3S/N) in the range of 0.001-0.008 mg·L⁻¹. Test for recovery was made by the standard addition method, giving recoveries in the range of 90.3%-111%, and RSDs (n=6) of the determined values were less than 5.0%. The proposed method was used for the analysis of actual samples, and the contents of 4 small molecule substances in the complete extraction solution were lower than those in the dissolution extract except for UVE. The content of UVE in the dissolution extract was significantly higher than that of the other 4 substances, and it was speculated that UVE was physically doped into the raw material embryo.