Spectrophotometric determination of phenol by flow injection on-line preconcentration with a micro-column containing magnetic microspheres functionalized with Cyanex272

A novel magnetic adsorbent, magnetic microsphere functionalized with Cyanex272, has been successfully synthesized via a chemical bonding alkylation method. A flow injection on-line preconcentration, with a micro-column packed with the as-synthesized magnetic adsorbent, coupled with UV-Vis spectrophotometric method was developed for the determination of phenol at a wavelength of 270 nm. Various experimental parameters were optimized as follows: eluent (methanol), sample flow rate (1.4 mL min−1), sample volume (1.4 mL), sample pH (5.0), and eluent flow rate (2.2 mL min−1). Under the optimum conditions, the intra-day and inter-day relative standard deviations were 1.37% and 2.69% (n = 5), respectively. The proposed method has been successfully applied to the determination of phenol in phenol ear drops, compound borax solution, and phenol ointment samples and the accuracy was assessed through recovery experiments.