study of different magnetic nanocomposites as additives in azolla modified copper electrode for improving the sensitivity of sensor in determination of phthalic acid esters via surface blocking effect

Abstract: nanoscale materials and devices have been widely explored in the last 20 years [1]. nano magnetite (fe3o4) is one of the magnetic materials with applications in the electrochemical methods due to its strong super paramagnetic property, low toxicity and easy preparation [2]. at this work, it was tried to design a sensitive and efficient electrochemical sensor for determination of some phthalic acid esters (paes) including dibutyl phthalate (dbp), dimethyl phthalate (dmp), di(2-ethylhexyl) phthalate (dehp) and dicyclohexyl phthalate (dchp) in aqueous solutions with differential pulse voltammetry (dpv) via paes blocking effects on the surface of azolla modified copper electrode in reduction of electrochemical responses of fe2+/fe3+. herein, different magnetic and mesoporous nanocomposites were used for modification of electrode surface to detect trace amounts of paes in aqueous solutions. for this purpose, various magnetic nanocomposites including azolla+fe3o4@ag, fe3o4@azolla, azolla+fe3o4@cmk, azolla+fe3o4 mnps, azolla+fe3o4@sio2@sba-3, azolla+fe3o4@sio2@sba-15, azolla+fe3o4@sio2@kit-6, azolla+fe3o4@sio2, azolla+nife2o4, azolla+kit-6-nh2, azolla+fe3o4@sio2@tio2, azolla+sba-15, azolla+kit-6, azolla+cu np, azolla+sba-3 and azolla+go np were added as surface electrode modifier and were investigated. according to the dpv responses, fe3o4@azolla modified electrode showed the best responses and was selected for further studies. therefore, the surface of the copper electrode was modified with fe3o4@azolla powder and electroencephalography gel. the modified electrode was characterized by field emission scanning electron microscopy (fesem). in the presence of paes as electrode blocker, the dpv responses of redox pairs of fe2+ and fe3+ was decreased proportional to increase in paes concentration. a comparison was made between dpv responses of azolla modified electrode and fe3o4@azolla modified electrode. after paes injection on the surface of fe3o4@azolla modified electrode, anodic peak current was decreased more than azolla modified electrode and the dpv responses were improved between 39.3%-72.5%. linear relationships were found between the dpv responses and the log cpaes with lod = 0.11 μg l-1 and loq = 0.36 μg l-1. good recovery percentages ranging 91.7-101.0% with rsd < 2.2 % suggested the proposed method for sensitive, accurate and quick determination of paes in real water samples.