Magnetic Solid-Phase Extraction Based on Poly 4-Vinyl Pyridine for HPLC-FLD Analysis of Naproxen in Urine Samples

A magnetic solid phase extraction technique followed by liquid chromatography with a fluorescence detector for naproxen analysis in human urine samples was developed. The method includes the extraction of naproxen with a magnetic solid synthetized with magnetite and poly 4-vinylpriridine, followed by the magnetic separation of the solid phase and desorption of the analyte with methanol. Under optimal conditions, the linear range of the calibration curve was 0.05?0.60 ?g L?1, with a limit of detection of 0.02 ?g L?1. In all cases values of repeatability were lower than 5.0% with recoveries of 99.4 1.3%. Precision and accuracy values are adequate for naproxen (Npx) analysis in urine samples.