Development and validation of a LC method for the separation and determination of the anticancer-active FeIII(4-methoxy-salophene) using the new second-generation monolith

LC method with the newly introduced second-generation monolithic silica RP-18e column has been developed for the separation of FeIII(salophene) and four methoxy-substituted FeIII(salophene) complexes. The method has been validated for the quantitation of FeIII(4-OMe-salophene), a highly active anticancer substance in vitro, bound to serum albumin. Our routinely used high-resolution continuum-source atomic absorption spectroscopy method based on the determination of the central iron atom was unsuitable in this case because serum originally contains significant amounts of iron as revealed by a blank sample of serum albumin. The developed LC method depends on detecting the whole complex rather than the bound iron. Two morphologically different first- and second-generation HPLC monolithic columns have been compared for this purpose. The newly introduced second-generation monolithic silica column Chromolith (R) HighResolution RP-18e column (100 x 4.6 mm, Merck) separated the mixture successful within 13 min. A mobile phase consisting of 25 mM phosphate buffer pH 3/methanol (60:40, v/v) was used at a flow rate of 1 mL/min. The dynamic linear working range of the calibration curve for FeIII(4-OMe-salophene) was found to be between 1 and 200 mu g/mL. Detection and quantitation limits were 0.3 and 1 mu g/mL, respectively.