Simultaneous HPLC determination of cholesterol, alpha-tocopherol, retinol, retinal and retinoic acid in silicone oils used as vitreous substitutes in eye surgery

A reverse phase high performance liquid chromatographic method for the simultaneous determination of cholesterol, alpha-tocopherol, retinol, retinal and retinoic acid in silicone oils, used as vitreous substitutes in eye surgery, is reported. The mixture components are removed from the matrix with recoveries close to 97% by solid-phase extraction with silica cartridges and subsequently separated on a C-8 column, using two different mobile phases consisting of acetonitrile/ammonium acetate and methanol/water that are passed sequentially. The compounds are detected by UV-Vis spectroscopy at two different wavelengths (210 and 350 nm) that are also set sequentially. The detection limits thus achieved range from 0.19 to 7.48 mu g mL(-1).