Spectrophotometric Determination and D-Optimal Design Optimization for Pre-Concentration and Separation of the Mixture of Acenaphthene and Pyrene Using Nano-Cobalt Ferrite Oxide Modified by Aspartic Aacid

A fast, simple, inexpensive, sensitive, efficient, and environment-friendly magnetic solid phase extraction (MSPE) procedure has been developed to concentrate two polycyclic aromatic hydrocarbons (Acenaphthene and Pyrene) from water samples prior to quantification by UV-vis spectrophotometric. CoFe2O4 nanoparticles modified by aspartic acid have been synthesized by co-precipitation processes.  This adsorbent was analyzed by FT-IR spectroscopy, SEM, and XRD methods. A D-optimal design was used for optimizing the factors and evaluating their influence upon extraction. The optimum experimental conditions were: pH= 3; sorbent dosage= 15 mg; Acenaphthene concentration = 150(µg/L); Pyrene concentration =400(µg/L). Under the experimental conditions, the method presents a good level of relative standard deviation for Acenaphthene and Pyrene, 2.9% and 3.1 % (n = 9; spiking level 5 mg/L) respectively. The detection limit for the Acenaphthene and Pyrene with 9 times measuring was 34 and 25 (µg/L) and the quantities limit was 84 and 114 (µg/L), respectively. Finally, the proposed method was applied to the analysis of four types of water samples, tap water, well water, river water, and effluent wastewater. The samples were previously analyzed and confirmed free of target analytes. At 50 (µg/L) spiking level recovery, values ranged between 80 and 90% for effluent wastewater samples showing that the matrix had a negligible effect upon extraction.