Magnetic solid-phase extraction and determination of ultra-trace amounts of antimony in aqueous solutions using maghemite nanoparticles.

A magnetic solid-phase extraction method was developed using maghemite as an efficient sorbent for the separation and preconcentration of antimony prior to its determination by ET-AAS. Maghemite was synthesized through a simple method and characterized by XRD, FT-IR and SEM. Various factors affecting maghemite synthesis, separation and preconcentration of antimony such as desorption solvent type, concentration and volume, desorption temperature and time, sample pH, amount of sorbent, and extraction temperature and time were optimized. The effects of interfering ions were also investigated. Under optimized conditions, the method exhibited good linearity (r2 > 0.9960). The sorption capacity and enrichment factor (EF) of the method were 37.5 mg g-1 and 242, respectively. The limit of detection (LOD) was 0.03 ng mL-1. The intraday, interday, and batch-to-batch relative standard deviations (%RSDs) were quite reasonable. The proposed method was applied to various real samples and the relative recoveries found were between 95.8 and 104.0 %.